Is materialism “known to be false”?

Schrodinger's cat(s)
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by Massimo Pigliucci

As RS readers know, I’ve recently been immersed for a long and fascinating weekend in discussions about philosophical naturalism and its consequences. Fresh from enlightening exchanges with the likes of Dan Dennett, Alex Rosenberg, Jerry Coyne, Sean Carroll and others, I however needed a bit of a break from the whole shebang. No such luck, as it turns out. A few days ago the newest issue of Philosophy Now automatically downloaded on my iPad, and the trouble started again. (I should clarify that I write columns for PN and even run a PN-sponsored philosophy meetup in New York, so what follows is not a criticism of the magazine, but of a particular piece by a particular author.)

The article that piqued my interest was penned by Graham Smetham, a Buddhist philosopher, author among other things of Quantum Buddhism and the Higgs Discovery: The Power of Emptiness. (Yes, my eyes did roll at reading that title.) The bottom line of Smetham’s article is that a number of philosophers — including the aforementioned Dennett — perversely insist in writing in the name of “known-to-be-false” philosophies of mind, philosophies that are, according to the author, flatly contradicted by quantum physics.

Having the memory of the naturalism workshop fresh in mind, however, I wondered why Carroll, or Nobel physicist Steven Weinberg, also present at the gathering, hadn’t bothered to correct Dennett and Rosenberg on their “known-to-be-false” philosophies. On the contrary, while there was much disagreement on the details, the physicists in the room seemed to broadly agree with the basic views of the universe espoused by said philosophers. What’s going on?

Briefly stated, the problem is that Smetham gets (much of) the science right, but draws fanciful and seriously unsubstantiated philosophical conclusions from it. This, of course, was precisely the topic of the workshop organized by Carroll: what philosophical implications can and cannot be derived from the best physics (and biology) available nowadays?

Smetham begins by quoting science writer Jim Baggott, who said apropos of the Higgs: “Mass is constructed entirely from the energy of the interactions involving naturally massless elementary particles ... The physicists kept dividing, and in the end found nothing at all.” Roughly speaking, this is the very same (correct, as far as I can tell) thesis developed by James Ladyman and Don Ross (the latter also present at the Carroll workshop) in their Every Thing Must Go, on which I have amply commented recently. One crucial difference is that Ladyman and Ross’ “structural realism” about physics (at bottom, there are no things, just mathematical relations and loosely structured fields) does not license the conclusion that things as we perceive them at the macroscopic level don’t exist, or are illusions. The special sciences, such as biology, deploy concepts like those of objects and causality (which do not apply at the quantum level) as a perfectly good description of real patterns at the level of analysis of those sciences. The table in front of you is very real indeed (try banging your head on it, just for fun), even though at lower molecular levels it is made of largely empty space, and at even lower levels it is “made of” collapsing wave functions.

But Smetham is a Buddhist, and such pluralistic interpretations of reality simply won’t do for him: if the bottom is made of structure and no things, then for him there is no sense in talking about things at all. Why? Because he wants to get what really matters to him: forget the Higgs, we are talking consciousness here. Contra the recent fashion in some skeptical circles, where talk of consciousness as “illusory” is getting perniciously commonplace, Smetham wants to go at the other extreme, deriving (allegedly) from quantum mechanics the conclusion that “at the quantum level ... the appearance of the material world is in some way dependent upon consciousness” (italics in the original, also in the quotes following). By the end of his essay, Smetham arrives at the position that “quantum theory clearly tells us that even the existence of a brain is the result of mental acts upon a deep quantum ground of potentiality. ... Consciousness, then, must be an essential quality of the quantum field, at least potentially.”

To begin with, notice the interesting caveat at the end: “at least potentially,” as if the author himself couldn’t quite believe the conclusion of his own syllogism. But the real problem is that there is nothing in the theory of quantum mechanics that implies a role of consciousness at all. 

To the best of my knowledge quantum mechanics qua scientific theory is made of a series of equations and boundary conditions. There is an entire school of physicists that stays clear of any high-level interpretation of it, and who amusingly refer to what they do as the “shut up and calculate” approach to quantum mechanics. Consciousness, at the human or quantum field level, simply doesn’t enter into it. Indeed, if one takes evolutionary biology seriously (and one really ought to), then consciousness quite clearly is a biological phenomenon, which evolved over a period of billions of years, and that is found only in certain groups of animals, to a variety of degrees that depend on the complexity and structure of their brains. As far as we can tell, no brain = no consciousness, so that applying the term consciousness to quantum fields is a category mistake.

It is hard to imagine what picture of the universe, and indeed what concept of consciousness, Smetham holds. Does he think that quantum fields are conscious? Or that the mathematical relations that underlie even those quantum fields are capable of consciousness? But consciousness means the ability to experience sensations, to be self-aware and to reflect on such sensations and awareness. In what sense, then, would a quantum field or a wave function be conscious?

Smetham’s center piece is his invocation of the alleged necessity of an observer to produce a collapse of the wave function. If by “observer” one means a sophisticated Homo sapiens capable of carrying out experiments in quantum mechanics, then it is a non-starter to say that reality becomes stable only through the presence of an observer. What was the universe doing before we came along? The other possibility is to imagine that the universe itself is in some sense conscious, at the very quantum level. In which case we run into the problems just mentioned, and into the additional one that the very term “observer” loses meaning if the whole quantum field qualifies as a conscious, what, entity?

But don’t take my words for it. Consult instead a very clearly written paper by physicist Michael Nauenberg, published in the Journal of Cosmology. Nauenberg states that “the view that the implementation of the principles of quantum mechanics requires a conscious observer is based on misconceptions.” He goes on to explain that what happens in reality is that there is an entanglement between any measurement instrument (the “observer” here can be an automatic recording device — again, no consciousness required) and the object being observed, because of course the device itself is subject to the laws of quantum mechanics!

Nauenberg explains exactly why entanglement and not consciousness is at the origin of the so-called “observer” effect, and concludes: “the wavefunction ψ is not a physical object like, for example, an atom which has an observable mass, charge and spin as well as internal degrees of freedom. Instead, ψ is an abstract mathematical function that contains all the statistical information that an observer can obtain from measurements of a given system. In this case there isn’t any mystery that its mathematical form must change abruptly after a measurement has been performed.” It is that (non-mysterious!) change that is referred to (misleadingly) as the “observer” effect.

Now, I can see (I think) what Smetham is struggling against. He is quite correct when he says things like “all apparently material structures and processes ... are emergent from insubstantial quantum ‘dream’ stuff” and “the ultimate material of the brain is ultimately immaterial.” But none of this licenses the radical conclusions to which Smetham quickly jumps. The reference to “dream stuff” is a colorful and misleading metaphor, as there is no dreaming (and no consciousness) involved in here at all, not until we fast forward billions of years from the Big Bang and focus on a pale blue dot of a planet on the periphery of an anonymous galaxy like many others.

I also think Smetham is correct on one important point: the best available physics does do away with “materialism,” if by that one means a view of the world based on “microbangings between microthings,” as Ladyman and Ross would put it. Since at the bottom there are only patterns and relations, no things nor bangings, then Newton-style, billiard balls materialism is indeed dead.

But I don’t know where Smetham gets his certainty that “materialism is currently a popular school in philosophy of mind,” accusing people like Dennett and Patricia Churchland of teaching a “known-to-be-false” doctrine. What Dennett, Rosenberg, I and pretty much everyone else who participated in the Carroll workshop espouse is naturalism, not materialism. There is a difference. We have known since Einstein’s days that matter isn’t the “basic” constituent of the universe, since matter is interchangeable with energy, so at the very least one ought to talk not of materialism but of “material-energicism” (a term unlikely to catch on any time soon, I’m aware). And more recent physics, as we have seen, goes even further, recognizing fields and mathematical relations at the bottom of all things (which, again, doesn’t license doing away with things at higher levels of structural complexity).

But naturalism is compatible with all that, and indeed more. I wrote recently about naturalistic forms of mathematical Platonism, which are ontologically compatible with physical structural realism (indeed, may even be implied by it). Naturalism — as opposed to supernaturalism — is a much bigger tent than mere materialism, and it represents the only available philosophical route outside of the arbitrarily made up stuff of theology. The fact that naturalism as a philosophy, and physics itself as a science, still have a long way to go to explain both the universe and consciousness is why naturalism is an exciting intellectual enterprise, not the “known-to-be-false” idol that Smetham makes out to be.

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Post Scriptum: Smetham plays the quotation game throughout his article, peppering it with a selection of statements by famous physicists that allegedly back up his views. Well, two can play that game. Here is a counter-list of quotations, courtesy of the above mentioned debunking article by Michael Nauenberg:

“Nature does not know what you are looking at, and she behaves the way she is going to behave whether you bother to take down the data or not.” (Richard Feynman)

“The universe presumably couldn’t care less whether human beings evolved on some obscure planet to study its history; it goes on obeying the quantum mechanical laws of physics irrespective of observation by physicists.” (Murray Gellmann)

“It may be somewhat dangerous to explain something one does not understand very well [the quantum measurement process] by invoking something [consciousness] one does not understand at all!” (Anthony Leggett)

“Caution: ‘Consciousness’ has nothing whatsoever to do with the quantum process.” (John  Wheeler)

“From some popular presentations the general public could get the impression that the very existence of the cosmos depends on our being here to observe the observables. ... I see no evidence that it is so in the success of contemporary quantum theory.” (John Bell)

Rather amusingly, Wheeler — but none of the others — is also quoted by Smetham, to contrary effect...