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, January 26, 2009

Strong inference and the distinction between soft and hard science, part I

In doing some research for my next book (on the differences between science and pseudoscience), I re-read this rather stunning piece of writing: “Scientists these days tend to keep up a polite fiction that all science is equal. Except for the work of the misguided opponent whose arguments we happen to be refuting at the time, we speak as though every scientist's field and methods of study are as good as every other scientist's, and perhaps a little better. This keeps us all cordial when it comes to recommending each other for government grants.” Candid words about the nature of the scientific enterprise as seen from the inside by a participating scientist. And what makes these sentences even more remarkable is that they were not uttered behind close doors in a room full of smoke, but printed in one of the premiere scientific magazines in the world, Science. It was 1964, the year I was born, and the author was John R. Platt, a biophysicist at the University of Chicago. The debate between scientists on what constitutes “hard” (often equated with good, sound) and “soft” (implicitly considered less good) science has not subsided since.

Platt was frustrated by the fact that some fields of science make clear and rapid progress, while others keep mucking around without seemingly been able to accomplish much of relevance. As Platt put it, in the same article: “We speak piously of ... making small studies that will add another brick to the temple of science. Most such bricks just lie around the brickyard.” Physics, chemistry and molecular biology are considered by Platt (and many others) as hard sciences, the quintessential model of what science ought to be. Ecology, evolutionary biology, and even more, fields like psychology and sociology, are soft sciences, and the maximal aspiration of people working in these fields is assumed to be to find a way to make their disciplines as hard as physics. Platt’s article is a classic that should be read by anyone interested in the nature of science, and he was right in pointing out the problem; he was not quite as right in diagnosing its roots however, and even less so at suggesting a possible cure.

Platt’s attack on soft science began by stressing the fact that some disciplines seem to make fast and impressive progress, while others have a tendency of going around in circles, or at best move slowly and uncertainly. Before we examine why this is and what could possibly be done about it, a more fundamental question is whether Platt is correct at all in identifying the existence of a problem. It seems clear from even a cursory examination of the history of science that Platt is at least partially correct: some sciences do progress significantly more than others. However, the pattern appears more complex than a line dividing “hard” from “soft” disciplines: it is true that, say, particle physics and molecular biology have made spectacular advances during the 20th century; but it is also true that physics itself went through long periods of stasis on certain problems, for instance the long interval on the question of the nature of gravity between Newton and Einstein. And such periods of slow progress may occur again in the future, even for “the queen” of sciences: for all the talk about a “unified theory of everything,” physicists have been trying to reconcile the known discrepancies between their two most successful theories, general relativity and quantum mechanics, for close to a century; they have not succeeded yet.

Organismal biology (ecology and evolutionary biology) is often considered a quasi-soft science, and yet it has seen periods of great progress -- most obviously with Darwin during the second half of the 19th century, and more recently during the 1930s and 40s. Moreover, there is currently quite a bit of excited activity in both empirical and theoretical evolutionary biology, which may be leading to another major leap forward in our understanding of how organisms evolve and adapt to their environments. Molecular biology, on the other hand, hailed by Platt as a very successful hard science on the model of chemistry and physics, may be in the process of running into the limits of what it can achieve without falling back on “softer” and more messy approaches to its subject matter: it is true that the discovery of the structure of DNA in 1953 is one of the all-time landmarks of science; but it is equally clear that the much-touted sequencing of the whole human genome has provided very few hard answers for biologists, instead leading to a large number of “bricks laying around the brickyard,” as Platt would have put it. We know a lot more about the human (and other) genomes, but much of what we know is a complex mess of details that is difficult to extricate and to make into a clear picture of how genomes work and evolve.

All in all, it seems that one can indeed make an argument that different scientific disciplines proceed at dramatically different paces, but it is also true that the very same science 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).

If we agree that the nature of science is along the lines that I have just described, next we need to ask why it is so. Platt briefly mentions a number of possibilities, which he dismisses without discussion, but that we need to pay some attention to before we move to his main point. These alternative hypotheses for why a given science may behave “softly” include “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 scenario 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.

The other 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 difference that money makes in 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 much 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, as well as the significant social impact of a few iconic figures, like Einstein (when was the last time you heard someone being praised for being “a Darwin”?).


  1. The "hard is better than soft" argument strikes me as rather juvenile. It is also not implausible to me that there is some latent sexism involved.

    As I argued in a comment elsewhere on this blog, in some ways the social sciences are "harder" than the "hard" sciences. The behavior of electrons doesn't change from day to day—if it did it's hard to imagine that physics would have progressed as it has. The behavior of humans is far more dynamic and complex than that of elementary particles.

    To be clear, I am not taking the contrarian position that the sciences traditionally labeled as "soft" are superior to those labeled "hard". Rather, I would prefer that we abandon the whole pissing contest!

  2. I should probably wait until Part II, but no guarantees I will ever return so here it is...

    I read Platt's paper for the first time in October (I'm a graduate student in physics).
    As for the second scenario you mention (that of an intelligence differential between fields), clearly bs, but what maybe true is a skills differential as a consequence of the standard methodologies employed. You'll probably touch on this in part II, but quantitative methods and communication between theory and experiment is a reasonably good recipe for science. The fact that the undergrad biology programs that I know almost discourage mathematics is an indication that biologists are, or at least were, less mathematically inclined (See Bill Bialek's intiative to change this) and that will affect the methodologies used and the direction they take the field. This then plays into a second point about the skill differential: the nature of the work. If people are attracted to what they like, there are probably many more galoshes-in-the-mud ecologists than there are nature obsessed high-energy physicists, because that's the image the field portrays. That's not to say there aren't mathematical ecologists nor forest-happy particle physicists, but their numbers are probably lower. Again, this will affect the direction the field takes. Fields probably do better when they attract people with a mix of skills (e.g. craftspeople and seers, to use a recent dichotomy by Lee Smolin in 'The Trouble with Physics').

    As for the money issue, that may entice those in search of fortune, but I would argue that coolness and money don't always correlate. Take theoretical high energy physics. It takes the 'smartest' (read 'most technically adept manipulators of current theoretical structures') kids in physics, mostly, I think, because therein lies a idealistic though naive notion of solving the mystery of the universe. Witten is the new Einstein, in a somewhat diluted, larger and American form. Nevertheless, try getting a job in that field today. I've heard it's next to impossible unless you are top cred. Not a good financial choice. On the other hand, I recall the neat anecdotes of the beginnings of chaos (mostly from James Gleick's book of the same name) of directionless but 'adept' post docs finding their calling analyzing the time series of water dripping out of a tap in the basement while big money accelerator-style physics research went on overhead. I would argue that the former has made more of an impact (perhaps leading to a higher coolness factor), despite costing next to nothing.

    A question: I was unaware that physics was losing its proportion of funding. Would this be a consequence of the increase of funding in biology? Apparently the fastest growing field in physics now is biophysics. Go figure.

    Bottomline: the hard/soft distinction applied to fields is bull. To methodologies of science, I would say less so...

    ps. enjoy Guelph.

  3. Hasn't Darwin had as much, if not more, social impact than Einstein?
    I can't imagine the general public getting mad at Einstein for special relativity and time dilation.

  4. I like the idea that "soft" sciences are the ones that are in some sense harder. But I think the idea needs more development.

    Think of a Jigsaw puzzle for example. If the picture contains a large amount of unique details it allows for a large variety of methods of analysis for solving it. A blank jigsaw is far harder and far less interesting. Intelligence gives you very little advantage because you are basically stumbling around at random anyway.

    And think of the games we play. A good game is complex but allows a large variety of ways to analyze the possible moves. These are exactly the games where more intelligence has a higher payoff. A bad game gives no tools to pick a path through the combinatorial explosion of possible moves.Intelligence makes little difference.

    Physics is cool because it is complex enough not to be trivial yet tractable enough so you have some hope of finding a path from problem to solution. In the soft sciences it is often hard to even define the problem with any precision let alone find a solution.

  5. Are the "bricks" even the same? Is one data point in physics the same as one data point in ecology? If the amount of money that was given to physicists for the LHC were given instead to paleontologists or marine biologists, how much would the latter advance their respective sciences? I'm a biologist. I understand the notion that biology is easier than physics. I got A's in botany and zoo, C's in physics and calculus. But there is also just a flat out difference between the sciences. Whether "soft" or "hard" we need to determine the importance. It may be way cool to know that there are planets circling other stars or finding out what dark matter is but I'd really rather have clean air to breath, pure water to drink and cures for debilitating diseases.

  6. Great long post! Good writing style =)

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  7. I don't think all sciences are equal because there are sciences such as psychology which can be very fuzzy
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  8. The more I think about this distinction between hard and soft, the more I find that it is false. At first glance, the hard sciences do appear to be more accurate, more predictive, and more able to be replicated. However, is this not the result of the absurd reduction that these hard sciences make of natural phenomena? In a test tube or testing chamber one can limit factors and causes to the point where it might appear that greater progress is being made in the acquisition of knowledge. Yet when one attempts to apply this knowledge in a non-lab setting, the same uncertainties that bedevil the soft sciences re-emerge. Take for instance geo-chemistry versus chemistry. So in the end, perhaps the distinction should be between reductionist or laboratory science and inclusionary or non-lab science without any judgment as to the validity or usefulness of either.


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