About Rationally Speaking


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.

Monday, June 02, 2008

Soft vs. Hard Science, part II

[This post is a second excerpt from the draft of a chapter of my forthcoming book, Nonsense on Stilts: How to Tell the Difference Between Science and Bunk," to be published next year by the University of Chicago Press]

As I wrote a few days ago, if we agree that the nature of science is along the lines I have described, next we need to ask why it is so. Platt, in his classic 1964 article on strong inference, briefly mentions a number of answers, which he dismisses without discussion, but that I think are actually a large part of the reason "hard" and "soft" sciences appear to be so different. These alternative hypotheses for why a given science may behave “softly” include, as Platt puts it, “the tractability of the subject, or the quality of education of the men [sic] drawn into it, or the size of research contracts.” In other words, particle physics, say, may be more successful than ecology because it is easier (more tractable), or because ecologists tend to be dumber than physicists, or because physicists get a lot more money for their research than ecologists do.

The second option is rather offensive (to the ecologists at least), but more importantly there are no data at all to back it up. And it is difficult to see how one could possibly measure the alleged differential “education” of people attracted to different scientific disciplines. Nearly all professional scientists nowadays have a Ph.D. in their discipline, as well as years of postdoctoral experience at conducting research and publishing papers. It is hard to imagine a reliable quantitative measure of the relative difficulty of their respective academic curricula, and it is next to preposterous to argue that scientists attracted to certain disciplines are smarter than those who find a different area of research more appealing. It would be like attempting to explain the discrepancy between the dynamism of 20th century jazz music and the relative stillness of symphonic (“classical”) music by arguing that jazz musicians are better educated or more talented than classically trained ones. It’s a no starter. [Aficionados of classical music don't jump on me: it's just an illustrative analogy, and I love classical music too.]

The other two factors identified and readily dismissed by Platt, though, may actually carry significant weight. The obvious one is money: there is no question that, at least since World War II, physics has enjoyed by far the lion’s share of public funding devoted to scientific research, a trend that has seen some setback in recent years (interestingly, after the end of the cold war). It would be foolish to underestimate the importance that money makes to science (or anything else, for that matter): more funds don’t mean simply that physicists can build and maintain ever larger instruments for their research (think of giant telescopes in astronomy, or particle accelerators in sub-nuclear physics), but perhaps equally important that they can attract better paid graduate students and postdoctoral associates, the lifeblood of academic research and scholarship. Then again, of course, money isn’t everything: our society has poured huge amounts of cash, for instance, into finding a cure for cancer (the so-called “war” on cancer), and although we have made progress, we are not even close to having eliminated that scourge -- if it is at all possible.

Part of the differential ability of scientific disciplines to recruit young talent also deals with an imponderable that Platt did not even consider: the “coolness factor.” While being interested in science will hardly make you popular in high school or even in college, among science nerds it is well understood (if little substantiated by the facts) that doing physics, and in particular particle physics, is much more cool than doing geology, ecology or, barely mentionable, any of the social sciences -- the latter a term that some in academia still consider an oxymoron. The coolness factor probably derives from a variety of causes, not the least of which is the very fact just mentioned that there is more money in physics than in other fields of study, and even the large social impact of a few iconic figures, like Einstein (when was the last time you heard someone being praised for being “a Darwin”?).

The third reason mentioned but left unexamined by Platt is the relative complexity of the subject matters of different scientific disciplines. This is a crucial and yet constantly under-appreciated point, even though it seems to me trivially true that particle physics does in fact deal with the simplest objects in the entire universe: atoms and their constituents. At the opposite extreme, biology takes on the most complex things known to humanity: organisms made of billions of cells, and ecosystems whose properties are affected by tens of thousands of variables. In the middle we have a range of sciences dealing with the relatively simple (chemistry) or the slightly more complex (astronomy, geology), roughly on a continuum that parallels the popular perception of the divide between hard and soft disciplines. That is, a reasonable argument can in fact be made that, so to speak, physicists have been successful because they had it easy. This is of course by no means an attempt to downplay the spectacular progress of physics or chemistry, just to put it in a more reasonable perspective: if you are studying simple phenomena, are given loads of money to do it, and you are able to attract the brightest minds because they think what you do is really cool, it would be astounding if you had not made dazzling progress!

Perhaps the most convincing piece of evidence in favor of a relationship between simplicity of the subject matter and success rate is provided by molecular biology, and in particular by its recent transition from a chemistry-like discipline to a more obviously biological one. Platt wrote his piece in 1964, merely twelve years after Watson, Crick and Franklin discovered the double helix structure of DNA. Other discoveries followed at a breath-taking pace, including the demonstration of how, from a chemical perspective, DNA replicates itself; the unraveling of the genetic code; the elucidation of many aspects of the intricate molecular machinery of the cell; and so on. But by the 1990s molecular biology began to move into the new phase of genomics, where high throughput instruments started churning a bewildering amount of data that had to be treated by statistical methods (one of the hallmarks of “soft” science). While early calls for the funding of the human genome project, for instance, made wildly optimistic claims about scientists soon been able to understand how to make a human being, cure cancer, and so on, we are in fact almost comically far from achieving those goals. The realization is beginning to dawn even on molecular biologists that the golden era of fast and sure progress may be over, and that we are now faced with unwieldy mountains of details about the biochemistry and physiology of living organisms that are very difficult to make sense of. In other words, we are witnessing the transformation of a hard science into a soft one!

I have much more to say, of course, about the soft-hard science continuum, but you will need to wait until the book comes out, hopefully by the end of 2009. Till then.

10 comments:

  1. You've missed a critical step.

    In part I, you argued fairly persuasively that the distinction between "hard" and "soft" sciences could not be drawn primarily or fundamentally on the degree or rapidity of progress. In part II, you appear to be jumping into a causal explanation of why some sciences become "hard" and others remain "soft".

    What's missing is some precise, explicit, objectively determinable definition of what constitutes hardness and softness in science. Our intuition will take us only so far. You and I, for example, appear to disagree whether psychology is a hard or soft science.

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  2. TBB,

    I don't think there is any critical step missing. In the first part I suggested that the rapidity of either empirical or conceptual process is what most people use to discriminate between soft and hard science (particularly, what Platt used in his 1964 article).

    One does not need precise definitions of concepts to effectively use them (just refer to Wittgenstein's discussion of family resemblance concepts like "game" for instance). Indeed, it can be argued that too much insistence on sharply defined concepts is precisely what gets lots of people into trouble to begin with (witness the absurd amount of time biologists waste in discussions of what, precisely, a biological species is).

    In the case at hand, even though I cannot come up with a quantifiable assessment of how much progress particle physics has made compared to, say, astrology, I'm pretty sure that the former has made a lot of progress, the latter next to nothing. That's enough to classify astrology as a very soft "science" (indeed, as downright pseudoscience).

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  3. n the first part I suggested that the rapidity of either empirical or conceptual process is what most people use to discriminate between soft and hard science...

    Wait, what?

    I read the first part as an argument that the rapidity of progress is *not* a good distinction between hardness and softness. If sciences we intuitively classify as hard "may undergo fits and starts, sometimes enjoying periods of steady and fast progress, at other times being bogged down into a spell of going nowhere, either empirically (lack of new discoveries) or theoretically (lack of new insights)," then the rapidity of progress would seem to be not a good definition.

    You have hypothesized two factors other than hardness/softness which cause lack of progress. One cannot use an effect with multiple causes to infer a particular cause.

    One does not need precise definitions of concepts to effectively use them...

    In science precision and objective definition is very important, and precision is critically important when defining a measured quantity.

    One does not need absolute, perfect precision (it's unattainable anyway) but the perfect is the enemy of the good.

    I think precision is very important in philosophy as well.

    In the case at hand, even though I cannot come up with a quantifiable assessment of how much progress particle physics has made compared to, say, astrology, I'm pretty sure that the former has made a lot of progress, the latter next to nothing. That's enough to classify astrology as a very soft "science" (indeed, as downright pseudoscience).

    Wait, what? You just did come up with a quantifiable assessment" "a lot" and "next to nothing" are assessments of quantity. Not a very precise assessments, but it's a start.

    Perhaps an even more fundamental ambiguity in this analysis is that you've offered no precise, unambiguous definition of "progress".

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  4. Just FYI: I've said what I have to say; I won't bother you further with my naive commentary.

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  5. TBB,

    no bother at all. One of the reasons I keep this blog is to engage people in conversation. I just wish I had much more time to devote to it.

    Anyway:

    "I read the first part as an argument that the rapidity of progress is *not* a good distinction between hardness and softness."

    Sorry not to have been clear. Progress is a good measure of a science, however subjectively measured. Fits and starts simply mean that progress may not be linear, which suggests that one needs to be careful not to pick stretches of time when one science is not progressing and another is, and claim that therefore the first one is soft and the latter hard. Wait another century and the roles may be switched.

    "In science precision and objective definition is very important, and precision is critically important when defining a measured quantity."

    There is a distinction between clarity (which I value in both science and philosophy) and precision. As I said, I think precision is much overestimated, especially by scientists.

    "You just did come up with a quantifiable assessment" "a lot" and "next to nothing" are assessments of quantity. Not a very precise assessments, but it's a start."

    I don't think so, "a lot" is a subjective and imprecise judgment, nothing that would ever get you a precise quantification. I never said one cannot make (very valuable) relative judgments, I'm just skeptical of precise measurements of a science's worth.

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  6. Massimo,

    I disagree with your interpretation of Platt's paper. I think he is not telling the difference between "hard" and “soft” science, in any case he distinguishes between "hard" and "soft" scientific method. Any scientific field could move forward faster (be a "hard" science) if scientists working in this field make use of a "hard" scientific method. He pointed out the stronger inference is a very effective method and showed two areas that have profited from it use(it is not means that only these areas are "hard" sciences, any field can take profit of the strong inderence; perharps 40 years ago molecular biology and high-energy physics were the best examples to stress the importance of this method). I think the last paragraph reflects this position:

    "When whole groups of us (followers of the strong inference, independenly of the field) begin to concentrate like that, I believe we may see the molecualr-biology phenomenon repeated over and over again, with order-of-magnitude increases in the rate of scientific understanding in almost every field" (p. 352)(brackets mine).

    He encourages to scientists of all fields to practise the strong inference so "When multiple hypotheses become coupled to strong inference, the scientific search becomes an emotional powerhouse as well as an intellectual one" (p. 350). I think the paper is good and, 40 years ago, probably it was a important paper, worthy to be published in Science.


    Marta Linde

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  7. Marta,

    except I don't actually think that strong inference can be used in but a small number of fields and problems. As I argue in the book I'm writing, even molecular biology now is finding itself to have to resort more and more to "fuzzy" statistical tests rather than strong inference. This happens every time the subject matter becomes complex enough that simple yes/no questions do not apply anymore. Another example is non-equilibrium thermodynamics in physics itself.

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  8. Massimo,

    I agree with you, the strong inference fell behind, but Platt's message continues being valid. I like very much this paragraph:

    "Beware of the man of one method or one instrument, either experimental or theoretical. He tends to become method-oriented rather than problem oriented. The method-oriented man is shackled; the problem-oriented man is at least reaching freely toward what is most important. Strong inference redirects a man to problem orientation, but it requires him to be willing repeatedly to put aside (including the strong inference) his last methods and teach himself new ones" (p. 351, blancket mine)

    Marta Linde

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  9. This entry from my favorite comic strip goes very well with this topic:)

    http://xkcd.com/435/

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  10. [I had, rather stupidly, posted this in the comments for part I, even knowing there was a part II, so I'm transferring it to this here; Massimo already did touch on some of the things I mentioned]

    In my amateurish view of these more philosophical discussions, it boils down to what complexity theory tells us.

    In my opinion, it's not necessarily the science itself that is intrinsically 'hard' or 'soft'; the fault lies with the different subjects said science studies -- the more amenable (from the complexity theory point of view) subjects can be studied in a 'hard' manner, while complex subjects cannot.

    Let me flesh it out a bit more so you guys can tell me whether I'm too far out there or if there is something to what I'm saying.

    What do I mean by "amenable", first of all? Amenable here would be anything that is composed of very few interacting parts, very simple; and also amenable would be something with a huge number of interacting parts. The complex subjects would be the ones in the middle, too intricate to fall in the first group, but too small to boil down to statistics as the second group.

    So, sticking to physics, which is not my area so please pardon (and correct) any mistake. physics has lots of simple systems to study, things that you can isolate and control all the variables. Even in the most mind boggling experiments in a particle accelerator, what they are doing is looking at too particles colliding at high speed. In the other end of the spectrum, physics also enjoys the study of the humongous system. And by that I mean, for example, a cup of water. There is a ridiculously large amount of molecules in that cup, and therefore the individual behaviour of small amounts of water molecules does not matter. They become part of very predictable statistics (temperature, viscosity, surface tension, etc.). The physicist can't get at these measurements by looking at individual water molecules, but has to look at a huge amount of them together.

    But I think even physics has its "in between" subjects. I'm more hard pressed coming up with these, but one I'm thinking of now is the many body problem or whatever was the name, where "many" means more than 3 interacting bodies. In such cases, there are no equations, and one must resort to numerical solutions, simulations, etc. 'Less hard' that Boyle's law, isn't it?

    So, fields like sociology or ecology are probably doomed to be soft, since their subjects of study are much more complex and irreducible than what physicists usually study. Molecular biology went 'hard' because it went much more reductionist than other areas of biology, therefore simplifying its subject. But you can't simplify societies or ecosystems to study them, because they don't exist anymore if decomposed -- that's why I think these will never be 'hard' in the way physics is, although that's not a problem either.

    Just my U$0.02... Well, given the dollar's worth nowadays, make that U$0.10, then.

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