<br><h3> Chapter One </h3> Hard Science, Soft Science <p> You know my methods. Apply them. Sherlock Holmes, The Sign of the Four <p> You can observe a lot by just watching. Yogi Berra <p> <p> "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 closed 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, and it provides us with our first glimpse into how difficult-and contentious!-it is to characterize science itself. <p> Platt was frustrated by the fact that some fields of science make clear and rapid progress, while others keep mucking around without seemingly being 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 other fields like psychology and sociology are soft sciences, and the highest aspiration of people working in these fields is assumed to be 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. Nonetheless, Platt's critique of what others often refer to as soft science provides us with an excellent starting point to explore the idea that, in fact, there may be more than one kind of science, that "science" is a heterogeneous category-a notion that would surprise most in the general public and that will likely be resisted even by a number of scientists. Moreover, our discussion will in turn open up the possibility that there may be ways to identify criteria that not only divide soft and hard sciences, but also separate disciplines that are not quite science yet (and perhaps will never become it) and others that are downright pseudoscientific. This is the task we will pursue over the first three chapters of this book in our quest to explore the complex intellectual landscape first identified by Popper's original demarcation problem. <p> Strong Inference and the Proper Way to Do Science (or Is It?) <p> Platt's attack on soft science begins, as we have seen, 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 thinking that there is a problem to begin with. 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 simple line dividing "hard" from "soft" disciplines: it is true that, say, particle physics and molecular biology have made spectacular advances during the twentieth century; but it is also true that physics itself went through long periods of stasis on certain problems, for instance the long interval between Newton and Einstein on the question of the nature of gravity. 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 succeed yet. <p> 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 nineteenth 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 to achieve a clear picture of how genomes work and evolve. <p> 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 a given science may undergo fits and starts, sometimes enjoying periods of steady and fast progress, other times being bogged down into a spell of going nowhere, either empirically (lack of new discoveries) or theoretically (lack of new insights). <p> If we agree that the nature of science is along the lines that I have just described, next we need to ask why this 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. <p> 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 different degree of "education" of people attracted to different scientific disciplines. Nearly all professional scientists nowadays hold 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 twentieth-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. <p> 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 (perhaps, not surprisingly, after the end of the cold war). It would be foolish to underestimate the difference that money makes in science (or anywhere 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 subnuclear 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. <p> 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 cooler 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"?). <p> Another reason mentioned but left unexamined by Platt is the relative complexity of the subject matters of different scientific disciplines. 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 into a more reasonable perspective: if you are studying simple phenomena, are given loads of money to do it, and are able to attract the brightest minds because they think that what you do is really cool, it would be astounding if you had not made dazzling progress! <p> 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 eleven years after James Watson, Francis Crick, and Rosalind Franklin discovered the double-helix structure of DNA. Other discoveries followed at a breathtaking 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 being able to understand how to create 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! <p> Despite all of the reservations that I detailed above, let us proceed to tackle Platt's main point: that the difference between hard and soft science is a matter of method, in particular what he refers to as "strong inference." "Inference" is a general term for whenever we arrive at a (tentative) conclusion based on the available evidence concerning a particular problem or subject matter. If we are investigating a crime, for instance, we may infer who committed the murder from an analysis of fingerprints, weapon, motives, circumstances, etc. An inference can be weaker or stronger depending on how much evidence points to a particular conclusion rather than to another one, and also on the number of possible alternative solutions (if there are too many competing hypotheses the evidence may simply not be sufficient to discriminate among them, a situation that philosophers call the underdetermination of theories by the data). The term "strong inference" was used by Platt to indicate the following procedure: <p> 1. Formulate a series of alternative hypotheses; <p> 2. Set up a series of "crucial" experiments to test these hypotheses; ideally, each experiment should be able to rule out a particular hypothesis, if the hypothesis is in fact false; <p> 3. Carry out the experiments in as clear-cut a manner as possible (to reduce ambiguities of interpretation of the results); <p> 4. Eliminate the hypotheses that failed step (3) and go back to step (1) until you are left with the winner. <p> Or, as Sherlock Holmes famously put it in The Sign of Four, "when you have eliminated the impossible, whatever remains, however improbable, must be the truth." Sounds simple enough. Why is it, then, that physicists can do it but ecologists or psychologists can't get such a simple procedure right? <p> The appeal of strong inference is that it is an extremely logical way of doing things: Platt envisions a logical decision tree, similar to those implemented in many computer programs, where each experiment tells us that one branch of the tree (one hypothesis) is to be discarded until we arrive at the correct solution. For Platt, hard science works because its practitioners are well versed in strong inference, always busy pruning their logical trees; conversely, for some perverse reason scientists in the soft sciences stubbornly refuse to engage in such a successful practice and as a consequence waste their careers scattering bricks of knowledge in their courtyards rather than building fantastical cathedrals of thought. There seems to be something obviously flawed with this picture: it is difficult to imagine that professionally trained scientists would not realize that they are going about their business in an entirely wrong fashion, and moreover that the solution is so simple that a high school student could easily understand and implement it. What is going on? <p> <i>(Continues...)</i> <p> <p> <!-- copyright notice --> <br></pre> <blockquote><hr noshade size='1'><font size='-2'> Excerpted from <b>Nonsense on Stilts </b> by <b>Massimo Pugliucci </b> Copyright © 2010 by Massimo Pugliucci. 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