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Rationally Speaking is a blog maintained by Prof. Massimo Pigliucci, a philosopher at the City University of New York. The blog reflects the Enlightenment figure Marquis de Condorcet's idea of what a public intellectual (yes, we know, that's such a bad word) ought to be: someone who devotes himself to "the tracking down of prejudices in the hiding places where priests, the schools, the government, and all long-established institutions had gathered and protected them." You're welcome. Please notice that the contents of this blog can be reprinted under the standard Creative Commons license.

Wednesday, February 27, 2013

On the causal completeness of physics


by Massimo Pigliucci

As readers of this blog know, I am not sympathetic to extreme reductionism, and reject both it and determinism in favor of a robust concept of emergence. Of course, I think a moderate epistemic reductionism has been the winning approach for science, and I agree that there is plenty of room for some degree of ontological reductionism (i.e., some times the whole is just the sum of its parts). But I’m not a fan of the everything-is-an-illusion-because-of-reductionism school of thought that seems so popular among skeptics and some scientists these days (see, for instance, my take on Alex Rosenberg’s particularly sharp articulation of that position).

Now, during my participation in the recent workshop on philosophical naturalism organized by Sean Carroll, I had an interesting exchange with physicist Steven Weinberg, who played what he thought was a trump card in favor of reductionism “all the way down”: he mentioned the causal completeness of the laws of physics. I asked him to elaborate on the point, and he said that the laws of Newtonian mechanics, for instance, are causally complete in the sense that there is no room within the equations for any unaccounted parameters. It follows, according to Weinberg, that those equations are a complete description of the causality of the system, leaving no room for emergent properties.

Okay, so the prima facie objection here is that Newtonian mechanics is known to be wrong, so it’s a bad example to make a case for extreme reductionism. Second, mathematically, Newtonian mechanics can be derived as an approximation of relativity theory, which means that — as it turns out — there were some parameters missing from Newton’s equations after all. Third, one can immediately raise serious philosophical issues concerned with the very meaning of “causality” being deployed here, and which specific form of theoretical reductionism Weinberg thought he was defending. But I figured that the guy knew what he was talking about (after all, I’m not the one holding a Nobel in physics!), so I took note and postponed further thinking on the issue until I had time to look into the primary literature on causal completeness. Now I have, and it turns out that things are more complicated, and interesting!

In this post I’ll comment in some depth on a paper by Agustín Vicente published in International Studies  in the Philosophy of Science (2006).

To set the frame for the discussion I cannot do better than to quote Vicente’s abstract verbatim: “According to an increasing number of authors, the best, if not the only, argument in favor of physicalism is the so-called ‘overdetermination argument’. This argument, if sound, establishes that all the entities that enter into causal interactions with the physical world are physical. One key premise in the overdetermination argument is the principle of the causal closure of the physical world, said to be supported by contemporary physics.”

In turn, the overdetermination argument goes like this (again, from Vicente), where “dubious” events are events that are alleged to be non-physical (such as mental causation, supernatural interventions, and the like):

(i) The principle of the causal closure of the physical (CCP): every physical effect (i.e., caused event) has physical sufficient causes;

(ii)  Causal efficacy of the “dubious”: dubious events cause changes in the physical world;

(iii)  No overdetermination: there is no dubious/physical causal overdetermination.

And the conclusion is that:

(iv) Dubious events are physical events.

As stated, I have no trouble with either the CCP or the overdetermination argument. I am a physicalist* [1], after all. But notice that the CCP as stated by Vicente bears only a family resemblance with what Weinberg invoked in our discussion. The CCP doesn’t state anything like that the laws of physics as we understand them now are causally complete. It simply states that, again, every physical effect has a sufficient physical cause. As such, the CCP excludes mental dualism (in philosophy of mind), vitalism (in biology) and supernaturalism (everywhere), but does not exclude emergent properties, as long as these are conceived as qualitatively new physical properties that manifest themselves under certain conditions of complexity and organization of matter. Another way to put this is that the CCP leads to physicalism, but physicalism does not logically entail extreme reductionism.

But why should we construe an argument like the one above in defense of physicalism to begin with? Vicente gives an interesting answer right at the onset of his paper. He says that it used to be thought that physicalism was a reasonable inductive inference arising from an historical trend of unification among all the sciences. That is, an epistemological argument could be made that, just like chemistry eventually reduced to physics (something about which not everyone agrees, actually), so eventually biology would be reduced to chemistry, and the social sciences would fold into biology. Et voilà le jeux sont faits, so to speak. Not so fast, as it turns out. There is an increasing agreement among philosophers (and, indeed, even Weinberg assented when I mentioned it!) that the actual history of science is taking a different trajectory, with the special sciences becoming more, not less, independent of physics, each operating at its own level(s) of complexity and explanation, with no hope of a true “theory of everything” coming along, ever.

That being the case, then, supporters of physicalism have to come up with an ontological account instead (which, again, is precisely what Weinberg tried at the naturalism workshop). This would be a theory that argues that while epistemic reductionism is practically impossible, ontologically speaking, it’s quarks (or strings, or whatever) all the way down. Which further implies that whatever laws describe the behavior of quarks (or strings, or whatever), they are the only laws of the land (and by land, I mean the universe), everything else is ontologically superfluous. Hence, the overdetermination argument above, which uses the CCP.

I could quit here and declare victory over Weinberg: the CCP that he invoked does not do the work that he thinks it does (specifically, eliminating the possibility of emergent properties), although it does do the job we both want it to do (eliminate dualism, vitalism and supernaturalism). But no, I just had to go on and read the rest of Vicente’s paper, didn’t I?

The question he goes on to address is an obvious one: why should we believe in the causal closure principle, particularly since it most certainly isn’t a law of physics? There are two classes of reasons: we could think of the CCP as a methodological principle guiding physicists (and, really, naturalists of all sorts, particularly skeptics) in their actual practice. Think of it as the Scooby-Doo principle: whenever you think there is a “dubious” (i.e., paranormal, extranormal, supernatural) effect at play, by the end of the episode it will turn out that it was just plain old physics (or biology, or whatever other science ends up offering the solution to the mystery). Alternatively, we could say that while the CCP is not strictly a law of physics, it is somehow supported by the laws of physics, and that’s a hell of a support!

By the end of the paper Vicente concludes that both lines of inquiry are fruitful. On the one hand, there are good inductive reasons to think that causal completeness is a valuable methodological precept. On the other hand, the principle can be connected to the laws of physics, and specifically to the laws of conservation. The arguments Vicente makes in the bulk of his paper are complex, and he does an admirable job at pointing out the difficulties of each. I will simply mention some of the highlights, to give you a flavor of what I think is a truly interesting and well written philosophical paper (one that Weinberg would do well to read, before talking about causal closure again, in my modest opinion. Ok, ok, that opinion wasn’t really that modest...).

One of the interesting notions emerging from Vicente’s historical analysis of the CCP is that it has not always been held during the history of science. Something like the CCP was entailed by atomistic-Epicurean physics, and then much later on by Leibnizian dynamics, but not at all times in between. Still, contemporary physics certainly does accept the closure principle as a strong methodological precept.

Vicente gets himself into what I think is unnecessary trouble, however, when he discusses emergentism. Here is what he says, verbatim (p. 153 of the article): “Emergentists would agree that physics is the science of the bottom level; nonetheless, they would claim that it cannot explain everything that happens in its domain, for some causal powers ‘emerge’ and bring about changes in the physical world that physics cannot explain. ... Some authors, such as Cartwright and Dupré, deny that physics is basic in the sense used here, that is, that it explains and describes the bottom level that somehow fixes or determines the rest of the facts of the world.”

But none of that seems to me in contradiction with the closure principle, as long as we understand emergent properties as physical properties, described by physical (or biological, or even social) laws or law-like generalizations. Remember, the CCP simply says that every physical effect has physical sufficient causes. To go further and somehow construe emergent properties as problematic for the CCP (or, as Weinberg would have it, the other way around) is a non sequitur. For instance, the best studied emergent properties are those pertinent to phase transitions (from solid to liquid, liquid to gas, etc.). But even if it turned out that the theory of phase transitions is irreducible to lower-level physical theories (because of the appearance of truly qualitatively new physical phenomena) we would still be talking about physical processes. Nobody is invoking a type of solid-liquid dualism, and certainly no one has suggested that the transition between liquid water and water vapor is the result of supernatural intervention!

Back to the main track. Vicente at one point (p. 154, if you are reading along) concludes that there is no good a priori justification of the closure principle, for three reasons: “(i) it cannot be justified by assuming reductivism, (ii) it does not follow from the fact that physics is a basic science (emergentists assume this, but they deny that it is explanatorily comprehensive), and (iii) it is possible to argue that physics is not basic.” He then goes on to explore the possibility that the CCP might be justifiable a posteriori, by induction.

Here again, the verdict is mixed. On the one hand — and despite the above mentioned discontinuous appearance of the closure principle in science throughout its history — it simply cannot be denied that the CCP has worked very nicely for physics: whenever physicists have looked for a physical explanation of a phenomenon, they found it. (Or, as Tim Minchin observed in a different context: “Throughout history every mystery ever solved has turned out to be, Not Magic.”) But theoretical biologists like Stuart Kauffman have also long pointed out that physico-chemistry has not at all been quite as successful at explaining biological phenomena. Kauffman and others (myself included) impute this failure to — you guessed it! — emergent properties arising from the interactions of complex systems of molecules, cells and even whole organisms. But once again I just don’t see why Vicente seems to think this is somehow a problem for the CCP understood as he presents it at the beginning of the paper. Kauffman and colleagues are most certainly not arguing for vitalistic forces, and much less for supernatural ones. But perhaps I am missing something fundamental here.

Finally, we get to the possible connection between the closure principle and physical laws as we understand them. According to Vicente there are two prominent venues of inquiry here: causal closure may be related to the action of forces in physics, or it may be connected to the idea of quantity conservation (such as the conservation of energy, or of momentum). Let’s take a quick look at both.

First off, notice that the discussion at this point is about what constitutes a cause (we are talking about the causal closure principle, after all!), a notoriously treacherous territory in philosophy, as much as it is often blissfully ignored by scientists.

Be that as it may, one basic idea (developed originally by David Papineau) is that physics has been able to expand its explanatory domain by invoking a smaller and smaller number of forces (currently, three: electroweak, strong, and gravitational). Ergo, there is no reason to think that in the future we are going to need more forces to augment our explanatory power (indeed, there are reasons to believe we’ll need fewer: that’s what the so-called “theory of everything” which physicists have been after for a while is supposed to do, to unify all the remaining forces in physics by way of a unitary account).

To make a somewhat long (but fascinating) story short, here is how Vicente summarizes the situation for the CCP in terms of its connection to forces in physics:

(i) Physical effects are, or involve, variations in the quantity of (the universally conserved) energy possessed by an object (body or whatever); 
(ii) The causation of physical effects consists in the action of forces; 
(iii) There is inductive evidence, partly negative, for the view that such forces are physical forces. 

Considering (i), Vicente points out that, in principle, the CCP could be questioned on the ground that not all physical effects involve a variation in the quantity of energy. Admittedly, though, it is hard to imagine which physical effects would fall within this unusual category.

Skipping for a moment to (iii), it can be questioned, in principle, by dualism, vitalism and emergentism, on the ground that its conclusion is inductive (and therefore tentative). As I said repeatedly above, however, I can’t figure out why Vicente thinks that emergentism is in the same category as the first two. All emergentism says is that some forces (or phenomena, more broadly) are not fundamental, that they only manifest themselves at certain levels of organized complexity. But these forces or phenomena would still be physical.

We are then left with (ii), the logical link to forces. Vicente doesn’t seem to like the invocation of forces to buttress the CCP, on at least two grounds: first, talk of forces actually smells a bit too much of classical mechanics, which has been replaced by a more sophisticated physics, to the point that physicists themselves may one day abandon any talk of force whatsoever, re-conceiving the whole shebang in terms, say, of fields and associate particles (Higgs!). He also claims that forces actually already play a secondary role in physics, with the main stage being occupied by conserved properties anyway.

Which is exactly where we turn at the end of this tour de force. The basic idea here is that causation is just the transfer of a conserved quantity; indeed, forces — in this conception — are not causes at all. Note that not all physical quantities can be transmitted (velocity, for instance, cannot). But if they can’t, then they don’t have causal powers (if you are thinking that a fast car hitting you does have causal power, you have to remember that the force of the impact is due to a transfer of another quantity, kinetic energy, not to the transfer of velocity).

While there is a certain intellectual and aesthetic appeal to defining causes simply as transferences of conserved quantities, so-called “CQ” theories of causality are just as controversial as theories of causality based on forces (I told you, causality is a mess!). I will leave it to the reader to work through the last part of Vicente’s paper to appreciate the nature of the controversy, but before closing I need to note that Vicente does admit that it is not possible to deductively exclude the existence of unknown forces, or of unknown quantities that can be transferred and are overall conserved. This is really not a particularly strong objection to either force/CQ accounts of causality or to the CCP itself. But it does mean that we arrive at the rejection of, say, new forces responsible for astrological effects (one of Carl Sagan’s favorite arguments against astrology) only inductively, and therefore in a potentially fallible manner. Not that any physicist or physicalist ought to be losing sleep over such matters, of course.

——

[1] The * after physicalism in my case is because I actually believe in an entirely natural ontology, but not necessarily an entirely physical one. For instance, I am attracted to mathematical Platonism. But of course mathematical objects (say, numbers) don’t violate the CCP because they do not have, per se, any physical effects.

96 comments:

  1. Are there any attempts to link the measurement problem in quantum mechanics and physical closure? I know that solutions to the problem which involve a role of the observer are not very popular these days but the fact that they are logically possible seems to leave open the possibility that physical reality is not causally closed. I wonder if a concept of emergence could be based on these issues.

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    1. Eliot Sober offers an account of the causal closure of the physics that can deal with the stochastic nature of quantum mechanics in his Physicalism from a probabilistic point of view. In short, physics is causally complete if adding higher-level special-science facts to the physical facts does not alter the likelihood of some event.

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    2. Assuming Bohr’s Copenhagen interpretation of quantum mechanics, the measurement problem does indeed have implications for our notions of physical closure and causality as well. This came to light at the 1927 Solvay conference on photons and electrons, where Einstein presented a simple thought experiment. If a single electron is transmitted through a single tiny opening towards a recording screen, then according to Bohr, it behaves as a wave until it is recorded, at which point the wave ‘collapses’ to behave as a particle. Einstein asked two questions. How does the electron ‘choose’ to record at a particular spot and how does it ‘know’ not to record elsewhere? In this thought experiment, later abandoned in favor of the more complicated so-called EPR paradox using entangled particles, Einstein pointed out what were, for him, the two troubling aspects of wave collapse at detection, namely that the result of detection is not strictly determined, and that the ‘collapse’ is non-local.

      Physicist Antoine Suarez argues that if physicists are to take the Copenhagen interpretation seriously, and a recent survey showed that most still adhere to it, then they cannot avoid facing Einstein’s questions. If we define the material as that which exists within relativistic space-time, then there must be non-local, i.e. non-material, coordination at measurement between all the points on the detector. A local alternative to this is de Broglie’s pilot wave, which posits a real particle plus a complementary non-energetic (hence undetectable, hence non-scientific) information wave that goes everywhere except where the particle is going, and it is this wave that “informs” the screen not to record elsewhere, and also accounts for the interference effect in the two-slit or Mach-Zehnder interferometer experiments. This local interpretation of quantum mechanics, which worked for a single particle, was put to rest by John Bell for entangled particles, and de Broglie’s model was expanded by David Bohm to include non-locality.

      So, Suarez argues, if we assume Copenhagen (i.e. ‘collapse’ at detection), then we cannot avoid accepting influences that are outside relativistic space-time, and we must accordingly abandon relativistic physical closure and causality. If we insist on saving materialism, we must expand the physical-material to include what is outside relativistic space-time, and causality to include non-time-ordered action over distance, but that would be stretching semantics to the breaking point.

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    3. Thank you for this link.
      However I had mentioned the measurement problem specifically because I think that reducing quantum mechanics to its stochasticity (as if it were a kind of probabilistic extension of classical mechanics) is misleading, although I have the feeling that it is what most philosophers do when discussing these issues (if ever QM is mentioned at all). So my question was rather: are there any discussion on physicalism/causal closure which take quantum mechanics seriously into account (beyond stochasticity)?

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    4. I don't think Bohr's version of complementarity with respect to QM viewed the wave function before collapse as physically ontologically real. There are numerous qoutes from him to this effect.

      I do think QM is relevant to the causal closure issure and the divided views on emergence. Mostly I think the views, like with QM interpretations are divided on ideology rather than experimental evidence.

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    5. Seth_blog

      > I don't think Bohr's version of complementarity with respect to QM viewed the wave function before collapse as physically ontologically real. <

      I agree, and it is the reason I used the phrase "behaves as". What the electron is before and after detection is unknown, perhaps unknowable; we only know the effects that we observe: interference, probabilistic and not deterministic location upon detection, and non-locality. These observed effects are enough to make us question our intuitions about physical closure and causality.

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  2. The flaw in science is measure.
    Removing this flaw from an equation reduces the equation to absolute, closure if you will.
    An example:
    e = mc2
    e = m
    =
    By removing the measurement of the speed of light, the equation is reduced to energy equals mass, which can be further reduce to equal, the equation or absolute that unites us all. Einstein came close to a unified field theory but then was stopped by C, something he had been taught to believe.
    Had he understood nature to be truly immeasurable, the truth science has yet to see, he would have solved the problem of everything. TOE.
    Its time for a revolution.
    Try it and see.

    =
    MJA

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  3. Quentin,

    > Are there any attempts to link the measurement problem in quantum mechanics and physical closure? <

    Not that I know of, but it's an interesting thought.

    > I wonder if a concept of emergence could be based on these issues. <

    Not completely. The problem with emergent properties is that the term may actually pick a very heterogenous category, so that one approach may not fit all. For instance, in some sense some physical forces "emerge" from a smaller set of forces through symmetry breaking when energy levels become low enough, but that emergence is - I think - well understood by physicists. Then there are phase transitions, which are much less understood. Then there is high-level emergence in biology and ecology, which is understood pretty much not at all.

    MJA,

    I have no idea what you are saying, actually. Measurement is one of the key components of doing science, not a flaw. You can't just arbitrarily remove a measurement (say, of the speed of light) and still have a coherent physical theory. Maybe we are close to a revolution, but I doubt it's the one you envision.

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    1. Massimo

      If you are still searching for the absolute of physics or the truth of philosophy I would suggest One remove any uncertainty from the equation or doubt from One's thoughts. This Method worked for the great problem solver from Ulm and also Descartes in a hotel in Ulm.
      "The people of Ulm are mathematicians." Sadly Descartes reduced truth to "I" and then allowed his own doubts back in. Einstein too knew the solution to any problem can be found through the process of reduction or simplification. But it was measure that stood in his way. Sadly he died in a quagmire of mathematics searching for the equation that he had come so close too, that absolute that would set him free.

      God doesn't play dice Professor M, but science does. The flaw of science is measure and because science failed to reduce Nature to its single absolute, to its single truth, to its infinite immeasurability, you and science and philosophy find yourselves debating probability, uncertainty, theories, and faiths into the quagmires of your own complex abyss.

      The light at the end of the tunnel called truth or absolute will unite not only the disciplines of science and the fractions of religion, but will also redefine justice, and Democracy.

      Truth is self-evident.
      And if you are going to build your castles in the sky make sure the foundation is absolute true.

      At the center of an equation is the equation itself.
      What does mankind or Nature fight for, the balance of Equality. we are fighting for truth!
      What was the Civil War about? Feminism? Lincoln, Gandhi, King, what were they about? EQUALITY

      So back to your question Professor, what is science without the divisiveness of uncertain measure? The same as religion without its divisions. "Imagine" as John Lennon would say. I would say simplify by removing any doubt, and that self-evident truth or light will be all that remains.
      The truth that will set us free.

      Evolution anyOne?

      =
      MJA
      New Ulm



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  4. A couple of terminological suggestions:

    1) It seems that the main target of your arguments is eliminative materialism. I think it’s likely to be misleading to call this view “extreme reductionism,” since we usually think that anything that is reduced is real – because we have shown how it fits into the underlying physics. When we identify water with H2O we don’t conclude that water isn’t real, we conclude that it is H2O.

    On the other hand, when we cannot reduce something to the underlying physics, then (according to the eliminativist) we conclude that it doesn’t exist at all. So we say that caloric and the aether are unreal, because they cannot be reduced.

    2) It would probably be helpful to distinguish between strong emergentism and weak emergentism.

    Strong emergentism is the claim that there is something ontologically and causally novel that emerges when parts interact in complex ways to produce higher-level entities. This is the view of, e.g., C. D. Broad. Strong emergentism is incompatible with the causal closure of physics. It says that even a Laplacean demon who knew all the physical laws and the complete physical state, and who had unlimited powers of calculation, wouldn’t be able to predict how those physical particles would behave when they formed, e.g., a mouse. The demon would have to know additional facts about the biological laws, and there would be no way, even in principle, to divine those laws from the facts of particle physics.

    Weak emergentism, on the other hand, is just a denial of elminativism. It is the flip side of ontological reduction. Temperature emerges from the motions of the molecules of a gas because temperature can be ontologically reduced to those motions.

    We might need more fine-grained distinctions to wade through debates on non-reductive physicalism (although I argue that strong and weak is enough), but clearly we need at least this much.

    Vincente is right that when one speaks of “emergentism” without qualification in philosophical circles, one usually has strong emergentism in mind. Broad and E. J. Lowe are emergentists in this sense (and Chalmers is strong emergentist about consciousness, though he doesn’t question CCP) . If we only mean weak emergentism, then this would capture all physicalists who aren’t eliminativists (which is the vast majority of physicalists).

    Note too that the causal closure argument discussed by Vincente takes as a premise the claim that the higher-level “dubious” feature is causally efficacious. This is itself a rejection of eliminativism – it’s saying that the feature is real, and then we use CCP to conclude that it’s physical.

    "The CCP doesn’t state anything like that the laws of physics as we understand them now are causally complete."

    Here you seem to be touching on Hempel’s dilemma, which is the worry that given that current physics is likely to turn out to be false, we can’t really say what an ontology of physicalism amounts to. I wrote an Analysis piece (links not allowed?) in which I argue that Weinberg’s basically right: we have very good evidence that our current physics is enough to account (in principle) for all biological processes, mental processes, etc.

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    1. Peter,

      thanks for your thoughtful comments. A few remarks for further discussion:

      > It seems that the main target of your arguments is eliminative materialism. <

      I’m not positive about this, and the reason should become clear from my following comments. Basically, though, I have a problem with Rosenberg-style reductionism, as in “the [fundamental] physical facts fix all the facts.” I’m not convinced that this is anything more than a reasonable but empirically unsubstantiated assumption.

      > It would probably be helpful to distinguish between strong emergentism and weak emergentism. <

      Indeed, and my interest here is with whether and in what sense one can articulate a form of strong emergentism. I find weak emergentism to be trivially true. If you haven’t take a look at the papers discussed in my previous series on emergence to see what I mean (http://rationallyspeaking.blogspot.com/2012/10/essays-on-emergence-part-iv.html).

      > Strong emergentism is incompatible with the causal closure of physics. <

      Perhaps, though I think that depends on what one means by “causal closure.” As I point out in the post, if that simply means that the only causes that can have physical effects are physical causes then I don’t see why that excludes even strong emergentism (it would exclude Chalmers-style dualism though!). Of course, the way you define causal closure is indeed incompatible with strong emergentism.

      > Here you seem to be touching on Hempel’s dilemma, which is the worry that given that current physics is likely to turn out to be false, we can’t really say what an ontology of physicalism amounts to. <

      That’s right, and I don’t buy Weinberg’s response to this. I’d be interested in your paper, and so would our readers. Links are allowed in comments.

      > our current physics is enough to account (in principle) for all biological processes, mental processes <

      Yeah, that’s what Weinberg said at the naturalism workshop, but when I pushed him on what the principle in question was he said something along the lines of “I can’t think of...” which to me amounts to a simple argument from ignorance. Not convincing, even coming from a Nobel prize winner...

      > Eliot Sober offers an account of the causal closure of the physics that can deal with the stochastic nature of quantum mechanics ... physics is causally complete if adding higher-level special-science facts to the physical facts does not alter the likelihood of some event. <

      But that is precisely what is in question, isn’t it?

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    2. I'd also love to read the Hempel's dilemma paper, if you've got a link.

      I have a question about your description of strong emergentism:

      "It says that even a Laplacean demon who knew all the physical laws and the complete physical state, and who had unlimited powers of calculation, wouldn’t be able to predict how those physical particles would behave when they formed, e.g., a mouse."

      Would you consider this equivalent to a description like the following?:

      It says that if one were to program a simulation of a physical system like a mouse, and the causality represented in the simulation included nothing but the causal interactions described by particle physics, the resulting simulation of the physical system would not act like a mouse at some systemic level.

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  5. I'm curious, why would you want to champion this kind of emergentism? What does it give you that supervenience physicalism doesn't? If everything in the world supervenes on the microphysical details that doesn't make the large-scale phenomena unreal. It's not reductionist in the sense that someone would think they know everything worth knowing just because they had mastered physics (though I doubt that such people exist anyway). Facts about higher level supervenient phenomena are non-obvious given the low level physical facts. The one follows from the other in ways that may be impossible to calculate in practice. Yes, it is still possible to say that the world is "nothing but" quarks or whatever, in the sense that the world is made out of these things and nothing else. But this (convenient) ontological reductionism doesn't have to imply a corresponding (absurd) epistemological reductionism.

    If emergent phenomena exist then they should be discoverable empirically. "Fundamental" particles will behave in anomalous ways when they are acting as part of some emergent collective. I imagine that Weinberg hates this idea, but more to the point he would probably say that we have no reason to believe that the world is like that. Do you think that there are physical phenomena that require this sort of explanation?

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  6. Hi Massimo,

    Thanks for your replies.

    >” I have a problem with Rosenberg-style reductionism, as in “the [fundamental] physical facts fix all the facts.”

    This formulation looks like a mere supervenience claim, which most take to be the definition of physicalism. If you reject even this, then you’re going beyond all the non-reductive physicalists I’m familiar with (e.g., Morrison, Wilson, Fodor, . . . )

    Rosenberg insists on an overly strong form of explanatory reduction (as I recall, it’s been a while since I’ve looked at Darwinian Reduction), but at the ontological level it seems to me that his position is one that all physicalists should be committed to. If he oversteps here too, it’s going to have to be something more than merely insisting on supervenience.

    >“ in what sense one can articulate a form of strong emergentism.

    I’d have thought that Broad and Lowe (for example) do a pretty good job of articulating what such a view would involve. Their accounts have the unfortunate feature of being false (and of denying physicalism), but they serve as a useful contrast class to a physicalist ontology.

    >” I find weak emergentism to be trivially true.

    I think it’s true, but I don’t find it trivial. Broad could have been correct (it was an epistemic possibility, at least), but he wasn’t. I’d say that one of the more important (and most underappreciated) discoveries of 20th century physics is that physicalism is true and strong emergentism is false.

    >” if that simply means that the only causes that can have physical effects are physical causes then I don’t see why that excludes even strong emergentism (it would exclude Chalmers-style dualism though!)

    It would exclude Cartesian interactionist dualism, but presumably not the more epiphenomenal (or dual-aspect) property dualism Chalmers defends.

    What particular feature(s) might you want to say strongly emerge (rather than weakly emerge) from physics?

    Nonreductive physicalists usually focus on casual features, and here I’m probably in the minority in thinking that physicalism requires causal reduction. It would probably take us too far afield to discuss my objections here, however.

    I’ll try to link to the paper again (analysis.oxfordjournals.org/content/early/2011/08/23/analys.anr087); it gave me an error last time. Perhaps I should see whether I’m allowed to post up a version on my website to make it available to the general public . . .

    In short, I argue that we good (though obviously a posteriori and defeasible) evidence that establishes the domain of applicability of our physical theories, and I argue that all biological and mental processes fall safely within the domain of quantum electrodynamics and classical Newtonian gravity. This is enough for causal closure with respect to terrestrial special sciences.

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  7. Oh boy, another attempt to argue for a dead universe that's intelligently constructed (metaphorically speaking anyway) with no purposes that this construct has evolved to serve.
    Paul Davies, among other physicists past and present, would beg to differ, but they say he's just too smart for his own good.

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  8. In Victor Stenger ("Causality is one of those commonsense notions, such as the world is flat") and Huw Price's micro-worlds, there is no causality. There doesn't seem to be any reason to suspect it physically exists anywhere.

    I would be suspicious and shake my head over any causality, emergence, or mathematical Platonism (it isn't needed) ... but that's me.

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  9. //, but does not exclude emergent properties, as long as these are conceived as qualitatively new physical properties that manifest themselves under certain conditions of complexity and organization of matter.//

    I don't see how. Emergence is different from saying that something emerges from something. I reductionist would say water-ness of water emerges from hydrogen atoms and oxygen atoms. Still the water-ness can be reduced to hydrogen and oxygen atoms. Water-ness can be explained in terms of hydrogen and oxygen atoms and their interactions.

    Emergence goes beyond that and states the water-ness emerges from hydrogen and oxygen atoms, but it cannot be reduced to oxygen and hydrogen atoms and their interactions. It has a physical component that comes out of nowhere. You'd have no idea where it came from. It just emerged. Now if you can come up with the a mechanism for their emergence, it would lead to reductionism again.

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  10. Massimo,

    >Okay, so the prima facie objection here is that Newtonian mechanics is known to be wrong, so it’s a bad example to make a case for extreme reductionism<

    Agreed, but note that the best available physics theory (the standard model) is also known to be wrong (or, at least, incomplete.) For instance, it cannot account for gravity in a consistent way. The difference between Newtonian mechanics and the standard model is that, while both are wrong, the standard model (which is based on quantum mechanics) is consistent with special sciences like chemistry. Newtonian mechanics could not account for the nature of chemical bonds, even in principle.

    A good formulation of the “causal completeness of physics” would be: “an unknown theory, based on yet-to-be-discovered mathematics explains everything.” On top of this, even the very expression “causal completeness of physics” seems inconsistent, given the fact that ordinary causality has no role in fundamental physics, as it has been known since the mechanical models of the “aether” were discarded over a century ago.

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  11. All,

    wow, lots of comments! I apologize if I’ll have to pick and choose for some brief responses. Please keep the conversation going!

    Chris,

    > I'm curious, why would you want to champion this kind of emergentism? What does it give you that supervenience physicalism doesn't? <

    As you point out, supervenience still allows Winberg to say that “in principle” it’s all about the fundamental laws of physics. It may be, but currently that ontological statement is a leap, and it is certainly contradicted by the prima facie empirical evidence. We all agree that epistemological reductionism is absurd, but I think it is more appropriate to be at least neutral about the ontological variety. I am interested in strong emergent properties because they would make the universe even more interesting than it already appears to be. Should they turn out not to exist, then fine, but I’m not willing to accept Wenberg’s “I can’t see why not” argument. It’s not an argument.

    Peter,

    > This formulation looks like a mere supervenience claim, which most take to be the definition of physicalism. If you reject even this, then you’re going beyond all the non-reductive physicalists I’m familiar with <

    Again, I’m not clear why. If emergent properties represent truly qualitatively novel behaviors of matter that seems to be beyond supervenience, and yet still a type of physicalism. Or are you arguing that physicalism entails fundamental reductionism? Why?

    > Their accounts have the unfortunate feature of being false (and of denying physicalism), but they serve as a useful contrast class to a physicalist ontology. <

    Again, you seem emergentism as denying physicalism, I don’t. If physicalism is simply the statement that all physical effects have to have physical causes, I’m on bard. It doesn’t follow that those physical causes have to reduce (ontologically) to the fundamental laws of physics. It’s an open question, in my mind.

    > I’d say that one of the more important (and most underappreciated) discoveries of 20th century physics is that physicalism is true and strong emergentism is false. <

    I disagree with the latter. It really doesn’t follow from the physics, and I bet you’d find a lot of non- fundamental physicists scientists who would argue about it.

    > presumably not the more epiphenomenal (or dual-aspect) property dualism Chalmers defends <

    Quite honestly, it isn’t clear to me what Chalmers defends, or on what basis.

    MJA,

    > If you are still searching for the absolute of physics or the truth of philosophy I would suggest One remove any uncertainty from the equation or doubt from One's thoughts. <

    I have no idea what this means, nor how to respond.

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    1. "I have no idea what this means, nor how to respond."

      The old Eastern Masters believed that the truth cannot be spoken, I believe the truth can be spoken but for many or most it simply can't be heard.

      Best wishes,

      =

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  12. Philip,

    > In Victor Stenger ("Causality is one of those commonsense notions, such as the world is flat") and Huw Price's micro-worlds, there is no causality. There doesn't seem to be any reason to suspect it physically exists anywhere. <

    That’s Stenger’s own limitation, he should read more philosophy of science. While it is true that fundamental physics, very interestingly, does away with causality, one simply couldn’t have any special science without deploying the concept (which is a major reason to think that the special sciences require something beyond fundamental physics, in terms of explanatory power). There are very interesting recent discussions on causality, some of which are linked in the main post.

    As for mathematical Platonism: http://rationallyspeaking.blogspot.com/2012/09/on-mathematical-platonism.html

    Zal,

    thanks for the thoughtful considerations. I’ll need to mull them over for a bit, I’m neither a physicists nor a philosopher of physics...

    brainoil,

    > I reductionist would say water-ness of water emerges from hydrogen atoms and oxygen atoms. <

    Give it a try. The physical-chemical properties of water are currently non predictable from lower level physics. They may or may not turn out to be in the future. Take a look at the links I posted on the literature on phase transitions, it’s fascinating.

    > Emergence goes beyond that and states the water-ness emerges from hydrogen and oxygen atoms, but it cannot be reduced to oxygen and hydrogen atoms and their interactions. <

    Incorrect. Strong emergence simply says that the “interaction” part gives origin to qualitatively new behaviors that cannot be predicted from lower level descriptions. I don’t see anything magical about that.

    > You'd have no idea where it came from. <

    One suggestion (again, see links cited above) is that it comes from the fact that the number of interacting particles tends toward infinity, which yields to a description in terms of mathematical singularities. Again, no magic.

    Filippo,

    > The difference between Newtonian mechanics and the standard model is that, while both are wrong, the standard model (which is based on quantum mechanics) is consistent with special sciences like chemistry <

    Yes, I have never denied consistency. But consistency is a much weaker requirement than ontological reducibility.

    > A good formulation of the “causal completeness of physics” would be: “an unknown theory, based on yet-to-be-discovered mathematics explains everything.” On top of this, even the very expression “causal completeness of physics” seems inconsistent, given the fact that ordinary causality has no role in fundamental physics <

    Amen to both statements!

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    1. Massimo,

      Having read the article you referred to, I am even more convinced that strong emergence is mistaken. A general rule is, if there is a singularity in your theory, it's probably false. They don't usually occur in nature. Any equation with a term like 1/X where X can go down to zero talks about a singularity. So even the water draining down my sink produces a singularity according to the equation. But that doesn't happen in nature.

      Secondly, a singularity is hardly an explanation for anything. It's an observation. I'm skeptical about physical singularities in general. But suppose that gravitational singularities are real and black holes exist and they are singularities. Still the singularity is not an explanation. It's by definition a mathematically undefined function. You still have to explain why the singularity occurs. Big Bang is supposedly a singularity. Okay but still we got to find out what caused the singularity. So you have to break it down and look for answers, and that will ultimately lead to reductionism because you can't properly explain a thing without breaking it down to smaller parts.

      I haven't read Batterman's original paper, and read just your blog post about it. But it seems to me he's saying theory X cannot be reduced to theory-Y because when it comes to P-transitions a Singularity occurs. I'd replace Singularity with The Force.

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  13. It seems that on the overdetermination argument, not only must "dubious events" be physical but "dubious entities" such as thoughts and beliefs must be as well: these things have physical effects and so by the argument (no overdetermination) they must be physical as well. A concern I have about this argument is the possibility that it gets causal completeness of the desired kind only by tacit expansion of the *definition* of 'physical' to include everything. Note that the conclusion that dubious events are physical events must be understood not as: whether they seem to or not, dubious events have conventional physical properties - but as: whatever properties dubious events have, those properties are now part of what it means to be "physical." The reason for this is more easily illustrated with dubious entities: Beliefs (for instance) must be physical entities according to the argument. This however cannot mean a change in the properties we ordinarily attribute to beliefs; they must remain weightless, locationless, spatially unextended entities that may be true or false, deeply held, and so on. What does change is that all of these properties become part of what we mean by "physical entity": some physical entities, to illustrate, have no location and are deeply held. Generally, it seems that the overdetermination argument works only by an effective tacit stipulation that all ontological categories are "physical" - whatever that means.

    Note that if dubious events and entities are not physical - a case that might be made on independent ontological grounds - then the overdetermination argument becomes a reductio on the CCP. Personally I suspect that the concern represented by the CCP, reductionism, emergence, and so on, arises from a mistaken view of causality: when causality is taken to be a physical process, or otherwise something with a special connection to physics, rather than a logical relation, all these sorts of problems arise. The problem I suspect is the ambition to understand everything in terms of physical mechanisms.

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  14. This comment has been removed by the author.

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    1. Filippo,

      This is a trivial point, but wetness isn't a property of water. It's property that other things have because of water. You can say the floor is wet. You don't say the river is wet.

      In any case, one H2O atom cannot make the floor wet, while water can. No one disagrees about this. Certainly one quark can't crash the stock market either. Again no one disagrees about this either. But you're saying that even if I knew every single thing I could know about quarks (or whatever the most fundamental thing there is), I still won't be able to predict the stock market crash even if I had unlimited computing power. Effectively this would mean universe simulation impossible even theoretically.

      I find this hard to believe. Suppose you are god. You just made the first quark. You make the second quark which would interact with the first quark. Now these two quarks will interact in such a way that you, the god almighty, cannot predict. Just where did this new property come from? Surely you, god, didn't create this new property.

      About renormalization groups, if you're referring to Batterman, I'm not convinced because he's talking about singularities.

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  15. Now, Paul, that short and concise presentation of your argument makes a lot of sense. Massimo clearly feels that physical forms are intrinsically functional, and why that either could or should be the case is not something that concerns his curiosity.

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  16. Philip,

    >In Victor Stenger ("Causality is one of those commonsense notions, such as the world is flat") and Huw Price's micro-worlds, there is no causality. There doesn't seem to be any reason to suspect it physically exists anywhere.<

    That causality exists somewhere can be easily proven by hitting your kneecaps with an heavy hammer. If you don't really believe that causality exists anywhere, you should be willing to try the experiment. If not, you are not really serious.

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    1. Filippo,

      There are serious views of causality other than that is something inherent in physical processes. Another serious view is that causality is properly analyzed as a complex logical relation between states-of-affairs. On this view what it means to say that hitting your kneecaps with a heavy hammer causes pain just means there is a certain logical relation between hitting you kneecaps and being in pain. Now while answering the question of why this causal relation holds would require a physical explanation, that the causal relations holds is an independent logical matter, one that can be known even if the physical mechanism is not understood.

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    2. Isn't a logical relation an intelligent relation? If so, Massimo cannot accept that possibility outside of the obvious use of logical considerations by some biological forms. Physical formations in nature are for him completely different than physical forms that have obtained the shelter of our earth. ir seems that as soon as you enter our atmosphere you are automatically exposed to the causative effects of a logical system.

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    3. Paul,

      I'm intrigued by the view of causality as a logical relation, but of course there must be more than just logic connecting a hammer and the pain on my kneecap. What, exactly? I like the suggestion mentioned in the main post that causality is a matter of exchanging conserved quantities between physical objects, but of course that would leave out some of the example you mention, where the "cause" doesn't really have anything physical to transmit. Could it be that "causality" is actually a heterogeneous concept, referring to different things in different contexts?

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    4. Could it be that causality involves awareness as an anticipatory function in a physical entity that will require a reaction to whatever forces it energetically encounters. And that the reaction will depend on the strategies (intelligently formed) that the entity has been evolved to operate with, either involuntarily or proactively, again depending on the nature of the awareness it has, over its history, been caused by an energetic nature to acquire. So that causation is an intelligent arrangement that nature continuously evolves, and that physicalists, by the logical limitations "caused" by their beliefs, are deprived of the ability to seriously consider.

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    5. Massimo,

      I agree of course that there must be more connecting the hammer-hit kneecaps and the pain than logic. This more however is not causality in some physical-process sense, but rather just a physical process that explains why the cause relation holds. This is really the same idea we have with logic generally: under specified normal circumstances, one's being hit on the kneecaps with a hammer implies that one feels pain. Here also a certain physical process explains why the logical relation holds, as opposed to "implication" being somehow mixed in with the physical process.

      So causality is not something inherent in physical processes but a complex logical relation that holds between states-of-affairs in in virtue of features of the relevant reality (which may be physical, intentional, etc; it's in the ontic variety of possible relata of the cause relation that the relation is heterogenous, on my view) and the context.

      Indeed context is important. In particular, what counts as the cause of something can depend on the background scheme of the person asking the question. To illustrate, suppose you drive by a friend's house at 2am and notice that all the lights in the house are on. The next day you ask the friend why the lights were on. The friend says she had to meet a deadline (as opposed to talking about about electricity and light switches - that's the physical schema). In this case something like the friend's desire to meet the deadline is the cause of the lights' being on. Now change the example so that the reason you wonder why the lights were on is that the power is out in the general neighborhood. In this case the cause might the friend having a generator - even if the friend is awake for the purpose of meeting a deadline. The suggestion here is that generally questions of causation are relative schemas of normalcy. If causation seems to be specially tied to physics, this is perhaps because the physics background schema is mistakenly assumed to be the only kind of possible background schema for causation.

      I wouldn't say that causality as a logical relation has been satisfactorily unpacked, but I think it's the right direction. I think David Lewis, with his counterfactual notion of causality, was on the right path (perhaps the only thing I agree with him about).

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    6. "This more however is not causality in some physical-process sense, but rather just a physical process that explains why the cause relation holds."

      I take back what I said earlier about you making sense.

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    7. "This is really the same idea we have with logic generally: under specified normal circumstances, one's being hit on the kneecaps with a hammer implies that one feels pain. Here also a certain physical process explains why the logical relation holds, as opposed to "implication" being somehow mixed in with the physical process."
      Under normal circumstances, feeling pain when a hammer hits your knee, is a signal that something has hit you there that shouldn't be encouraged. The "implication" is not that you feel pain, but that the pain implies that you felt the hammer. That's the purpose that is served by pain, an effect that identifies its cause. And you understand that instinctively even if your odd philosophy tells you purposes are metaphors for accidents, as pain has no purpose either.
      Of course if you don't think there's some connection between causation and the intelligence that recognizes it purpose, that would imply that you'll ramble on as usual.

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    8. Does a spoof that's grounded in the physical brain of a spoofer have the same physical properties as its own intelligence? Because it occurs to me that Paul here is either a very clever spoofer or is that rare phenomenal example of a self spoofer, where the intuition is devoted to gaming its (supposedly) more rational counterpart (or counter brain part if you will). Massimo on the other hand just lacks a part that, if lacking in Paul for example, would be seen by a part of him as missing.

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  17. Paul,

    Of course, causality exists in physical processes. For instance, the craters on the Moon were produced by asteroid (or cometary) collisions. The fact that there is no true causality in fundamental (microscopic) physics does not mean that there is no causality in the macroscopic physical world. After all, the macro world is emergent from the micro world and, as such, it acquires properties not inherited from the micro world.

    The macroscopic world even has forces that are not present in the micro world. One example is osmotic pressure. It is not given in detail by any of the fundamental forces (electro-weak, strong and gravitational.) Osmotic pressure is an example of an entropic force, driven by a reduction of free energy (or increase in entropy.) Entropy is not a fundamental physical concept, but an “emergent” one, useful when dealing with systems containing innumerable degrees of freedom. Entropic forces dominate life at the cellular level.

    The emergence of the macro world from the microscopic world of QM is also the subject of the modern versions of the Copenhagen interpretation. The old version simply postulated a separate micro and macro (or classical) world.

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    1. I am sympathetic to your (Filippo) description of entropy as an emergent force. I understand the textbook Copenhagen interpretation postulating separate micro and macro worlds, but would again suggest that this was not as Bohr intended.

      Bohrs version of complementarity saw the experimental measurement conditions as inseparable from the observed quantum phenomena, together they comprised a quantum system. So Bohr did not think of separate quantum and classical worlds. One world where new properties emerge resonates with my intuitions, and I think fits the data as well as other interpretations.

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    2. Seth,

      I totally agree that viewing the “classical” world as emergent is the only way to make the Copenhagen interpretation viable. However, there are many technical details involved: decoherence, measurement as a Bayesian update of knowledge, etc.

      Probably a discussion of this is beyond the scope of this blog. Still, I have to stress my own “metaphysical” prejudice: only the algebra of the (non-commuting) observables is (structurally) real. State vectors are purely epistemic: they represent states of knowledge. This explains why the fact that they collapse faster than the speed of light (as experimentally verified) does not violate special relativity.

      This is my answer to Zal: nonlocal collapse does not mean that “we must accordingly abandon relativistic physical closure and causality.” Properly interpreted, the “Copenhagen interpretation” does not violate special relativity, naturalism or (structural) realism, but it is a spectacular example of emergence.

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    3. The Universe doesn't play dice but science does.
      Beyond probability is absolute.
      Beyond uncertainty is certainty.
      Beyond theory is truth.

      =

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    4. Thanks Filippo,

      I am just a layman and am sure you are better versed in the details. I also don't want to wander to far off topic. I am interested in the topos theory that Doering and Isham have been pursuing. It employs commutative sub-algebras and an intuitionistic logic. Mostly it appeals to my prejudices as I am not fully qualified to critique it's validity.

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  18. I have a real emotional affinity for emergence. But it seems that it aught to be demonstrable. There aught to be experiments that show it exists. Epistemic emergence can be waved away as just a demonstration of our current ignorance. So there must be a way to show small atoms, for a lack of a better word, of emergence.

    We would have to (and by "we" I mean smart people) define the properties of emergence itself. An emergent property is not determined by smaller relationships. You would have to show that certain properties of water are not predicted or even caused by any properties of quarks. You would have to show that there is no way to know from quarks something about water. That something would be emergent.

    In your previous posts, you mention "phase." So I'm guessing that whether or not water is ice or gas would be considered emergent, because it requires you know temperature and pressure. So experimentally, you would have to show that this is not just because we don't have enough data.

    But my liking for emergence may be because it is almost self evident. It might the case that emergence isn't special at all. It might be that ALL properties of water are emergent. That emergence is really just a mystification of perspectivism. That a razor's edge isn't sharp to a molecule is an obvious sort of mismatch of perspectives. The sharpness of the razor is most important to the whisker, less so to the cell, and of no concern to the molecule.

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  19. What causes emergence and does so in such a predictably consistent fashion?

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    1. If that question can't be answered because nothing can be considered caused at all, what are the effects of emergence? Assuming that there can be uncaused effects. Or if there can't be, why do there appear to be emerging qualities that are uncaused and uneffective? Although if asking "why" is the same as asking for reasons that equate to pseudo purposes, then we have no cause to ask that question either.

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  20. Researching this, and as confused as when I was looking at physicalism or materialism. How do you take this stuff seriously when most of the liternature assumes that there is a clear difference between the physical and non-physical. But to be charitable and open-minded, let's call coffee cups physical things and ideas non-physical things. Let's also assume we live in a one-way causal world. THEN this stuff presents many challenges, as per Massimo but agreed - the system is closed.

    But what does this prove, what progress have we made?

    Let's look at at three supposedly very simple concepts (1) An event being a function of specific space-time 'point's (2) Newton's 3rd law (for every action...) and (3) Einstein's special relativity. Using (1) and (2), you can make the case that what happens to create an event is a combination of multi-vector causal forces, and using (1) and (3) how the event is interpreted is fundamentally up to any observer of the event, indeed, it determines what is the nature of the event.

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  21. Paul,

    > This more however is not causality in some physical-process sense, but rather just a physical process that explains why the cause relation holds. <

    Again, interesting idea. But then why is it that the logical relation of causality doesn’t seem to do any work at the quantum level? The physicists have an explanation: causality - qua physical relation - needs time asymmetry, which does not hold at that level.

    OneDay,

    > Epistemic emergence can be waved away as just a demonstration of our current ignorance. So there must be a way to show small atoms, for a lack of a better word, of emergence. <

    Funny you put it that way, because it seems to me that we are flooded by examples of emergence from the special sciences, from solid state physics all the way to ecosystem ecology. If anything, I’d like a good demonstration that ontological reductionism is the way to go...

    > I'm guessing that whether or not water is ice or gas would be considered emergent, because it requires you know temperature and pressure. So experimentally, you would have to show that this is not just because we don't have enough data. <

    It’s tough to prove a negative of that magnitude, but again, why is the burden all on the side of the emergentist, while the reductionist just gets to shrug shoulders and say “I don’t see why not”? The mathematical models characterizing phase transitions cannot in fact be reduced to lower level models, and lower level models have repeated failed to predict the properties of the emergent system. Yes, this could just be a temporary epistemic failure, but at the moment it’s a big one.

    Filippo,

    > The fact that there is no true causality in fundamental (microscopic) physics does not mean that there is no causality in the macroscopic physical world. After all, the macro world is emergent from the micro world <

    I am sympathetic to this view. Ironically, this would mean that so-called fundamental physics is pretty much the only area of science where one can be a true reductionist, everything else requires emergent properties. One of the physicists I quoted in my series on emergence said that - contra Weinberg - the more fundamental physicists do their thing the less relevant they are to the rest of science, including the rest of physics. That’s not because they are doing anything wrong, but because their level of analysis cannot address what’s important to most of the rest of science. Needless to say, Weinberg was not pleased.

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    1. Massimo,

      >But then why is it that the logical relation of causality doesn’t seem to do any work at the quantum level? The physicists have an explanation: causality - qua physical relation - needs time asymmetry, which does not hold at that level.<

      I don't see a problem with idea that causality qua logical relation depends on time assymetry as well; temporal ordering could be an incidental condition of causality qua logical relation holding. Generally, I don't see how time dependence is a problem for my view. On my view causality is part of a metric that we apply to reality to understand it in relevant ways, and such that it is broader than physics, as logic in general is. That causality wouldn't apply to a level of reality that humans knew nothing about until recently is consistent with the human-made notion of causality that I support.

      A similar question I would have for you is what you make of the fact that talk of causation is broader than physics. A false belief can cause a person to take the wrong train. A squirrel in the road can cause a driver to swerve. All such cases provide philosophical evidence regarding what is going on generally with the concept of cause.

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    2. I agree with you. I am just musing about what type of data could be convincing. Also about whether or not emergence is rare and important (consciousness and poetry) or commonplace and boring (phase shifts, lack of even a theoretical way to predict large scale phenomena from quarks). Personally, I'm betting that emergence is commonplace and important. I believe ontological reductionists miss the forest for the trees. Literally.

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  22. I think it's useful here to distinguish between two possible meanings of "emergent." One is that the theory devised to explain things at one level yields, when extended to another level, "surprising" results that were difficult for us to anticipate. This is the kind of "emergence" involved in making, say, macroscopic magnetism "emerge" from the interaction of individual iron atoms. The root is, essentially, nonlinear interactions between a large number of elements, which can cause the collective behavior of a system to deviate from the "sum of all parts" (i.e., linear) behavior. In this kind of "emergence" there is nothing added to (or missing from) the theory in going from one level to the other. I suspect this is the kind of emergence that Weinberg had in mind in his remark.

    Another kind of "emergence" refers to the fact that the theory devised to explain things at one level cannot explain things at another level. Barring non-physical causes (whatever that means), this kind of emergence must come from the existence of factors that are unimportant at one level (hence could be ignored when building the theory) but important at another (hence cannot be ignored when extending the theory). For example, that the speed of light is an absolute maximum (Einstein) can be ignored as long as we are dealing with much smaller speeds (Newton). I think this is the kind of emergence that Massimo is thinking of when talking about Newtonian mechanics.

    Personally I think that both kinds of "emergence" happen frequently in science, and it is hard for me to see any deep meaning in the word emergence that goes beyond the two listed above.

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  23. Hi Massimo,

    Thanks for continuing the conversation. (I’m afraid I’m traveling, and so can’t really keep up my end right now.)

    > ” If emergent properties represent truly qualitatively novel behaviors of matter that seems to be beyond supervenience, and yet still a type of physicalism.

    Of course, the term “physicalism” can and does mean different things to different people. I’m known for saying that today everyone is a nonreductive physicalist – they only vary in what they mean by reduction and what they think is required for physicalism.

    But I think it’s pretty widely accepted that physicalism requires at minium a commitment to supervenience. (See, e.g., Stoljar’s SEP entry.) That’s just the generally accepted terminological usage. So most people familiar with the debates will take the claim that you’re a physicalist to mean that you think that all facts about concrete events supervene on the microphysical facts.

    Strong emergentists like Broad are naturalists, but they’re not physicalists (again, as the term is widely understood). Broad saw his account of emergence as explicitly rejecting physicalism, and physicalists like me agree that strong emergentism is a quite separate view from ours, and we take pains to differentiate our (correct) view from his (mistaken) view.

    There actually are some tricky questions here about what sort of modal force is required for supervenience. If mere causal necessity were all that’s required, then the strong emergentist (and most property dualists) would count as “physicalists.” This has led to discussions of “superdupervenience” as a requirement for physicalism (see, e.g., this nice paper by Wilson). It has also led to discussions over whether the metaphysical supervenience demanded by physicalism needs to be an a priori link, or whether it can be a posteriori.

    > “ I bet you’d find a lot of non- fundamental physicists scientists who would argue about it.:”


    When scientists speak of reduction, they tend to have in mind a form of explanatory or methodological reduction. When the point is clarified, they almost never (in my experience) embrace a failure of causal/ontological reduction.

    Anderson’s “More Is Different,” for example, never questions the sort of causal/ontological reduction that physicalists insist on and that Broad (and other strong emergentists like Lowe) reject.

    All the best,
    P

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  24. Neither this post nor the comments to follow make any reference at all to the possibility that causation may be an intelligently self constructed aspect of all universal systems. Intelligence by your reckoning can exist on earth in humans, but the intelligent processes that they've discovered to be useful have, by your reckoning, never been discovered elsewhere, and that's of course because intelligence didn't exist before we (somehow) fashioned it to suit the uniqueness of our needs as living beings in a space where non-living entities must otherwise exist without the ability to use or take advantage of it - even if it otherwise could have existed at all outside of living beings.

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  25. Say there are these:

    P: P1|P2|P3| ... levels of phenomena (read by measuring devices)
    T: T1|T2|T3|... levels of theories (written in LaTex:Math, say)

    The lowest level (P1, T1) could include the measurements made in the Large Hadron Collider and the Standard Model. Higher levels could have to do with chemistry, biology, psychology, politics, ...

    Couldn't one talk in the terms of correlations (P) and consistency (T) instead of causality (P) and emergence/reduction (T)?

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  26. Paul,

    > temporal ordering could be an incidental condition of causality qua logical relation holding. <

    It doesn’t seem to be incidental, but necessary. It seems to me that for the concept of causality to make sense the case *has* to come before the effect.

    > talk of causation is broader than physics. A false belief can cause a person to take the wrong train. <

    Yes, I consider those instances interesting too, but as you know it is quite controversial - even in philosophy - whether those really do identify instances of non-physical causation (based on the obvious observation that beliefs are themselves grounded in physical facts about the brain, and therefore not outside of physics).

    brainoil,

    > A general rule is, if there is a singularity in your theory, it's probably false. <

    Go tell it to the physicists and mathematicians who disagree. My understanding is that a singularity instead appears when the number of particles in the system approximates infinity, as it is the case with phrase transitions.

    > a singularity is hardly an explanation for anything. It's an observation. <

    No, it’s a mathematical description, which is what one looks for in scientific explanations of physical phenomena.

    > You still have to explain why the singularity occurs. <

    In the case of phase transitions, because the number of particles tends to infinity. Did you really read the linked article? All of this is clearly explained there.

    > I haven't read Batterman's original paper, and read just your blog post about it. <

    Ah, that explains it. You may want to invest the time and read the actual paper.

    > About renormalization groups, if you're referring to Batterman, I'm not convinced because he's talking about singularities. <

    Perhaps you should read his paper before dismissing it.

    Peter,

    > Strong emergentists like Broad are naturalists, but they’re not physicalists (again, as the term is widely understood). Broad saw his account of emergence as explicitly rejecting physicalism, and physicalists like me agree that strong emergentism is a quite separate view from ours, and we take pains to differentiate our (correct) view from his (mistaken) view. <

    Well, I do consider myself a naturalist but not a physicalist, in part because of my attraction to ontic structural realism, and even to mathematical Platonism. But it still seems to me that there is an intermediate position between the two you mention that is worth exploring. Namely, there doesn’t seem to be good a priori reason to exclude the (strong) emergence of qualitative new behavior when matters become complex/organized that still entail only physical events and causes. At least, if there is a good reason, I can’t see it. I only see a widespread a priori commitment to ontological reductionism, which seems to beg the question.

    Philip,

    > Couldn't one talk in the terms of correlations (P) and consistency (T) instead of causality (P) and emergence/reduction (T)? <

    Yes, one could, but then one would be asked to unpack the idea of correlation thus invoked, which I suspect would pretty quickly bring us back to talk of causality, emergence and reduction.

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    1. I read Batterman's original paper, since you regard it so highly.

      First, I think what he's advocating is a type of weak emergence, not the kind of strong emergence that you think is the case.

      Secondly, he's wrong to think that he has established emergence to be true. It seems that he's trying to establish emergence by appealing to the appearance of universality in the thermodynamic limit. Re-normalization group theory does show that processes in the thermodynamic limit exhibit universality. But that doesn't establish emergence. Universality is hardly an in-principle barrier to reducibility.

      Seeing emergence emerging out of universality in thermodynamic limit processes is like seeing god in a burning bush. It's not there.

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    2. Hmm, sounds to me like you did not actually understand Batterman's paper. He is not trying to "establish" emergence, since we already have plenty of examples of emergence. He is trying to see whether we can come up with good mathematical tools to describe it. And yes, he's talking about strong emergence. Your parallel with the burning bush is a complete non sequitur.

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    3. Well, if I didn't understand Batterman's paper, I have no way of knowing that. But here's what I thought. In his paper, Batterman doesn't make any sort of ontological argument for emergence. I don't know what Batterman's other views are about emergence. All I can say, as far as I see, that paper is not an argument for strong ontological emergence. I said his view is weak emergence because his view doesn't have some ontologically fundamental force emerging. His view is of course non-reductive, so in that sense it's a strong emergence.

      //He is trying to see whether we can come up with good mathematical tools to describe it.//

      It's not that it's a groundbreaking discovery that in order to derive thermodynamic properties from statistical mechanics you need a thermodynamic limit where certain properties go to infinity, and that all real things are finite (for example, the number of particles is finite), there is a problem.

      So to fix the problem, he brings up universality, and of course it is an attempt to establish emergence in thermodynamic limit. It's not as if emergence is an accepted theory like natural selection. My point is, you can't establish emergence that way. Universality is not an in-principle obstacle to reducibility.

      As for seeing god in a burning bush, I think it's appropriate. I mean, there are so many other ways to think about the problem. For example, suppose you have two theories, one called Newtonian Mechanics and the other theory of relativity. You don't know which one is true. But it seems that in order to derive Newtonian Mechanics from relativity, you need to make few assumptions that aren't even true (just like the thermodynamic limit in this case). So one approach to start thinking about this, even if you don't know which theory is true, is to think that at least one of those theories is perhaps false or an approximation. You don't need to think that the laws of physics themselves are stratified, and that the apple that fell on your head obeys laws that are different from the laws that govern planets.

      That's just one way of thinking about it. There are several others.

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  27. I think it's 'les jeux sont faits'.

    You may also want to change the last 'he' in 'the CCP that he invoked does not do the work that he thinks he does' into an 'it'.

    That's all I can really add to a challenging article. :)

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    1. wimvdb,

      many thanks! No martinis for our editor-in-residence this time!

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  28. Massimo
    'Yes, I consider those instances interesting too, but as you know it is quite controversial - even in philosophy - whether those really do identify instances of non-physical causation (based on the obvious observation that beliefs are themselves grounded in physical facts about the brain, and therefore not outside of physics).'

    This is the sticking point for me. I agree that beliefs are 'grounded' in the physical medium of the brain. I don't think we can assume that all the properties that emerge from the physical are themselves physical, or that beliefs can be reduced to the physical medium. It does seem to me that there are non-physical aspects of belief that constrain our actions. I am however, receptive to my uncertainty on this point.

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    1. Seth,

      it is a sticky point indeed, and I'm open about it as well. Remember, I'm open about granting ontological status to mathematical objects, so... I'm writing a new book now, on whether and how philosophy makes progress, and am working on a chapter on naturalism and Quine. Philosophers use the term "abstracta" for these kinds of non-physical entities. Quine was notoriously stingy with his ontology, but did allow mathematical objects. People like Ladyman and Ross are a bit more generous. Bottom line, the ontological status of abstracta is very much under debate!

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    2. How are we doing, debate wise, with the ontological status of intelligentsa and strategicsa? And metaphorica?

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    3. I have come across a paper in 'Information' by Joseph E. Brenner that attempts to address this 'sticky point'.

      The paper reviews Terrence Deacons 'Incomplete Nature' and compares it with his own 'Logic in Reality'. Brenner's 'Logic in Reality' is an attempt at a new logic that accounts for an inseparable relational natural ontology. The paper (so far) confirms all of my bias's by leaning on concepts like complementarity, mutual opposition, reciprocity, etc.... I am not sure yet if it provides anything novel or truly unifying to the debated concepts, or if it makes new predictions that can be tested.

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    4. Massimo would love this paper. It makes no reference to information as intelligence or as intelligently derived. Information operates by itself and neither has nor serves a purpose. It has no dualistic nature as it's a completely physically self regulated and mechanically directed function. It has a calculus oriented logic that's so mysterious that the paper can't, by our classical logic, completely explain it. I must have missed the part where it makes new predictions that can be intelligently tested, however.

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  29. I'm a bit confused as to how you can distinguish the emergence of new physical causes under certain conditions of complexity and organization of matter and vitalism which is in some cases merely the view that in the conditions of complexity and organization found in living beings some new causes, principles or what have you are necessarily found to explain the properties and behaviour of living matter. "Vitalists hold that living organisms are fundamentally different from non-living entities because they contain some non-physical element or are governed by different principles than are inanimate things." (http://mechanism.ucsd.edu/teaching/philbio/vitalism.htm)

    As far as I can see some species of vitalism are also species of strong emergentism. So I can see why Vicente views them as of a piece in places you find it odd.

    Note about Batterman, I always understood Batterman to point out that in order to explain why similar (but microphysically different) things are similar we often have to aver to a principle that is not justified microphysically. So it shows that explanations of similarity require new principles (or often old principles), however explanation is at stake not cause. Whether the principles that explain are thereby given an ontic status above say the principles of convention or formalism that are obviously required(eg. we can't do science always referring to individual sub-atomic particles), is highly dependent on various other controversial issues.

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  30. @ Massimo "As stated, I have no trouble with either the CCP or the overdetermination argument. I am a physicalist* [1], after all."

    You're flip-flopping again. Do you believe in NONPHYSICAl objects (e.g. mathematical abstractions)? Yes or no?

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    1. Alastair,

      I thought I had been exceedingly clear, both in this post and in others. My ontology is not limited to physical objects (it does, for instance, include mathematical ones). But "physicalism," in the context of the CCP, is NOT the idea that everything is made of matter, only the idea that all physical effects must have physical causes. I certainly don't disagree with that!

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    2. So, I ask as I channel Alastair, the things that are not made of matter are not made to have an effect on anything made of matter?

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    3. Baron,

      well, let's see, when was the last time that hitting the numeral 4 caused you to bleed from your nose?...

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    4. The last time I wrote the number on my nose I didn't hit it so I don't know. However, thinking about the numeral may have caused me to hit it on the computer.

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  31. The symbol for money ($) is located on the same key as the number 4. I can imagine a belief system placing high emphasis on money possibly playing some role in the causal pathways that eventually led some individuals to getting punched in their noses.

    Seeing the ($) symbol would still correlate with a physical response, and the actual bleeding would still require a physical cause. In this case would the cause be purely physical? It would seem to depend on how one thinks about information it's connection to the physical world.

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    1. In that Brenner paper all information was deemed to be physical - it can somehow convey meaning without intelligence. The possibility that we might have come to possess intelligence to understand the mechanics of that meaning system was not considered.

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    2. Seth,

      without a doubt belief systems have consequences. But that raises the question of the ontological status of belief systems. If you think of them in the abstract, then per se they do nothing physical. They require a physical medium (the human brain) to cause physical consequences. Same with numbers, ethical beliefs, and so forth. I like Paul Paolini's suggestions of thinking of causality in the broadest sense as a logical relation, which includes as a subset actual physical causality. That may go some way toward retaining the principle of causal closure while at the same time allowing for a broader naturalistic ontology than just physical objects.

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    3. Thanks Massimo,

      I think that is actualy similar to what Brenner is attempting. I think he would see causalty as a process and he has tried to define a relational logic that includes what is actual and what is potential (as an example of a non-separable pair in dynamic opposition). He feels this logic represents a natural ontology and can be useful across disciplines from physical sciences to information science to the social sciences. It is a bold claim and has not been receiving alot of notice.

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    4. Seth, Didn't I tell you that Massimo would love that paper?

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  32. No, Brenner's 'Logic in Reality' is based in part on in-separability. Information is neither all physical nor completely absent of everything physical. He would suggest that meaning emerges from the maximum interaction on the continuum between these antagonistic pairs (dynamic opposition).

    I doubt Massimo would like this new type of logic and he would I expect have good reasons for questioning it. I am just becoming familiar with Brenner's work. It sits well with my way of thinking, but I am likely not as well versed to identify it's shortcomings as Massimo and others here are.

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    1. There's no suggestion that these antagonistic pairs had any knowledge of what their antagonism either meant or portended. And this new type of logic has no reasoning involved or a capacity for formal argument. And yet it unexplainably conveys meaning.
      That's something that I'll have to not think about.

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    2. Yes, we are all well aware that you have one lense through which every theory must be filtered. It is a sure way to protect any new uncertainty from entering the frame. Humility and curiosity are not such scary concepts once you give them a try.

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    3. But now that the new uncertainty has entered our philosophical maw, should we taste it a bit before we swallow it, or not?

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  33. Posting on this topic a bit late. I've been mulling over it on and off for a week.

    I think I come down against strong emergentism, but not for any rigorously defensible reasons. It just feels wrong. "I don't see how...".

    I suspect that if I could articulate an argument against it, it would make the case that strong emergentism is essentially equivalent to magic.

    In order to explain why I think it is not correct, I will first try to explain the difference between "magical laws" and physical laws, and then to explain why strong emergentism smells to me like magic.

    It seems to me that the principal difference between magic and physical laws is that magic is not rigidly defined. Its rules are vague and inconsistent

    When Harry Potter says "Wingardium Leviosa" using his wand, he can make an object hover. This may seem to be a perfectly well defined law, but it isn't.

    1) We have not defined what constitutes a wand. What would happen if he shaved a couple of millimeters off the end of it? What would happen if we kept doing that until there was next to nothing left? At what point would the spell fail to work? What's the difference between a wand and a piece of wood?
    2) We have not defined what constitutes a Wizard. What is the difference between a Wizard and a Muggle? If it's a gene, then what proteins does that gene code for? If we injected these proteins into a Muggle, would they have magic ability? What if there were miniscule quantities of the gene?
    3) What constitutes the object that is levitated? Physical objects are composed of molecules, atoms, quarks etc. How does the spell know which atoms are to be levitated and which are not? In this case, it may not be so much of a problem - Harry only has to levitate a subset of the whole object and the rest of it will be brought along for the ride by the molecular forces binding them together - it's more of a problem for spells like transsubstantiation (as illustrated in the excellent Harry Potter and the Methods of Rationality).
    4) In any case, how does Harry Potter specify what subset of atoms he is grabbing hold of? Why doesn't he wind up levitating the air atoms in front of his wand instead of his broomstick several feet away?
    5) What judges whether he has pronounced the wording of the spell correctly? One could draw a smooth continuum of pronunciations from unintelligible gibberish to the correct pronunciation of "Wingardium Leviosa". At what point along the continuum does the spell work? In order to define this precisely, you would need to define an algorithm that would analyse the speech pattern and make the decision.

    The problems with this "magical law" go on and on. It's far too vague to work as it is, and even if we were to rigidly determine the answers to all these questions there are many more that crop up.

    The basic problem is that magical laws outline rules which apply to vague intuitive categories ("Wizard", "wand" "saying Wingardium Leviosa", "hover") which make sense to humans at a narrative level, but which cannot easily be given rigid mathematical definitions. If physical laws are mathematical in nature, as I take them to be, then magical laws cannot be physical laws.

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  34. I think many of the same problems apply to strong emergentism, because strong emergentism maintains that new physical laws apply when dealing with systems composed of simpler parts. The problem then is how to rigidly define such a system.

    For example, if we imagine that there is some new force of attraction between water molecules that does not exist at the next level down, that of hydrogen (H+) and hydroxide (OH-) ions, then that law only makes sense if we can rigidly define what constitutes a water molecule.

    And I'm not sure that we can. As far as I am aware, there is no fundamental point at which we can state categorically that we have a water molecule (H20) rather than a pair of hydrogen and hydroxide ions. There is a continuum of different levels of association/connectedness and at a certain point we say the ions are one molecule rather than two ions.

    One way to resolve the problem might be to imagine that the new force increases in strength as the hydrogen and hydroxide ions become more closely bound.

    But if that's the case, then the force exists in a weak form even at the level of relatively unbound hydrogen and hydroxide ions. We have taken a phenomenon we assumed to be a strong emergent property of a water molecule and reduced it to a property of ions.

    I feel the same is true of any strongly emergent property. If we have some difficulty in rigidly defining a water molecule, how much more hopeless is it to define more complex phenomena such as conscious minds.

    While strong emergent laws may not be logically impossible per se, they seem to me to be exceedingly unlikely due to the difficulty in rigidly defining the systems in which they might obtain.

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  35. Massimo wrote:
    >I thought I had been exceedingly clear, both in this post and in others. My ontology is not limited to physical objects (it does, for instance, include mathematical ones). But "physicalism," in the context of the CCP, is NOT the idea that everything is made of matter, only the idea that all physical effects must have physical causes.

    Hmmm… Massimo, this confuses me. I had thought that the main reason for postulating non-physical mathematical entities was that this was (supposedly) required to explain how we know truths in mathematics. But, if it is those non-physical entities which cause us to know truths about mathematics, then, given that our knowing those truths does involve certain physical changes in our brains (which I assume to be a fact of neurophysiology acknowledged by even non-physicalists), then it would seem to follow that those non-physical mathematical objects managed to have physical effects (i.e., in our brain).

    I realize of course that one could postulate non-physical mathematical objects but deny that they have any causal power in terms of our knowledge of mathematical truths. But, then, I fail to see what is gained by supposing their existence.

    Incidentally, although I am a physicist, I am not in your terms a physicalist, nor am I a believer in abstract objects, whether with or without causal powers. So, none of this is a dilemma in terms of my own views.

    I am just trying to understand where you are coming from. I’m sincerely puzzled.

    Dave Miller in Sacramento

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    1. I'm not Massimo but I am a physicalist platonist, so I can give you my perspective.

      Abstract objects such as mathematical objects do not have causal powers. Brain states reflecting beliefs about mathematical objects are not caused by those mathematical objects, but by physical interactions between particles.

      Explaining physical events or brain states in terms of abstract concepts such as mathematical objects or emergent physically-grounded concepts such as the stock market is only a device to help us understand what's going on. In principle, all physical events can be explained in terms of matter and energy.

      We don't postulate non-physical mathematical entities in order to explain how we know truths in mathematics. We postulate them to justify how it is reasonable to say we have mathematical beliefs - if these entities did not exist then the beliefs could not be true. "There is a prime number greater than 4 and less than 6" would be a false statement if the number 5 did not exist.

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    2. It's a non-physical mental thought process that's used to point out that the mathematical example of a physical truth is actually a tautological example of a truism. Beliefs, true or otherwise, use the mathematical logic that the minds of its believers invented.

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    3. Baron:

      I'm unclear as to the point you're making but I would suggest that you not take it for granted that mental thought processes are completely non-physical.

      They may reduce to computations carried out by physical interactions between particles, as in computer processors. This is a pretty mainstream belief in philosophy of mind.

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    4. No, that's not pretty mainstream at all. The brain is capable of creating concepts while mechanical computation systems aren't.

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    5. I disagree. And even if you were correct to doubt that it is mainstream, the question is far from settled.

      http://en.wikipedia.org/wiki/Computational_theory_of_mind

      http://plato.stanford.edu/entries/computational-mind/

      For my own reasons for supporting this view:
      http://disagreeableme.blogspot.co.uk/search/label/strong%20ai

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    6. I didn't say the question was settled. But your cited articles have some pretty mainstream thinkers on my side of the fence. And in any case, show me the computer that's capable of creating an abstract idea, which is what philosophy of mind is all about.

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    7. Sure, there are mainstream thinkers on your side of the fence. And on mine. My point is that it is certainly not a radical or fringe point of view, which is what I meant when I called it mainstream.

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    8. The brain is capable of creating concepts while mechanical computation systems aren't. What do your mainstream thinkers tell you about that?

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    9. I ignored that because it's not an argument but an assertion which I disagree with.

      Whether current AI systems are capable of creating concepts is debatable. Google computational creativity to get some idea what I'm talking about.

      In any case, none of this says anything about what AI systems may be capable of in principle. I believe they can in principle do anything human brains can do. You do not. I'm not going to debate it on this thread because it's off topic. If you want to get into it with me, I direct you to my blog.

      http://disagreeableme.blogspot.co.uk/search/label/strong%20ai

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    10. Of course my assertion is an argument for my side, and you're just dodging the request to make a better argument for your side. And of course it goes to the heart of what AI systems may be capable of in principle, because if they can't do the essential things that our brains have evolved to do now, where did you find the fundamental truth or principle that tells you otherwise?
      Off topic? It was you who stated that mental thought processes "may reduce to computations carried out by physical interactions between particles, as in computer processors." What was that, an assertion that wasn't up for argument? Why, because you meant it to be off topic?
      Why would I want to get into anything on your blog anyway? This blog is where the action is, if you understand the concept of action.

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    11. My statement was not an assertion. I used the word "may".

      Your original statement that mental processes are non-physical was an assertion. I'm not saying you're wrong (here), because to do that I would have to get into an off-topic debate. I'm just saying you can't take it for granted that mental processes are non-physical.

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    12. Come on, an assertion always has the "may" implied. Or since when were arguments only used to prove a certainty?
      And I don't take it for granted that mental processes are non-physical, I take it as a logical assertion. And that it's illogical to use mechanical computation as a counter assertion. (Use any dictionary definition of logic that you prefer of course.)

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    13. >Come on, an assertion always has the "may" implied.<

      >Use any dictionary definition of logic that you prefer of course.<

      I think a dictionary definition of "assert" would be more appropriate.

      "To declare with assurance or plainly and strongly; to state positively."

      Your statement "The brain is capable of creating concepts while mechanical computation systems aren't." is an assertion. There was no "may" implied. Unless you claim that your intention was to say "The brain may be capable of creating concepts but perhaps mechanical computation systems aren't".

      In contrast, I said that they "may reduce to computations". This is clearly not an assertion by any definition I have ever seen.

      I have no interest in discussing this further in this thread. I only wanted to suggest that you not state these things as facts which we should all assume.

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    14. But, DM, I do have an interest in continuing to correct what "may" be your mistakes.
      So it now seems that when you said that mental thought processes "may reduce to computations carried out by physical interactions between particles, as in computer processors," your response is that you were more specifically saying they may or may not reduce to computations, etc., no?
      And when you then state, "This is a pretty mainstream belief in philosophy of mind," you must have meant in the context of the previous comment that this may or may not be a pretty mainstream belief in philosophy of mind.
      Because if you didn't mean to say that, you might have omitted either the "may" or it's "may or may not be" version from your previous sentence entirely.

      And as far as suggesting I not state facts which we should all assume as facts,
      I should have added that "it should be obvious" that the brain is capable of creating concepts while mechanical computation systems aren't. Inviting you to state that it isn't obvious, and relieving you of the duty to state how or why mechanical systems really can create concepts.
      Because clearly the way I put the statement, you found a way to avoid a meaningful response anyway.

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    15. I had an interest in discussing how your own use of "may" didn't fit with your own next sentence, but I didn't save it, and as sometimes happens, it's has been lost in someone's shuffle.

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  36. >Remember, the CCP simply says that every physical effect has physical sufficient causes

    To me this claim is untestable and of little value. Can we not accurately describe any effect or cause as 'physical'? If so, the principle is simply that effects have causes. Bore me. If we consider, for example, that the force of gravity as non-physical then that opens the door to possible non-physical causes.

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