Theory and Reality

by Peter Godfrey-Smith

  Here is one more comparison, which is more complicated and requires more background knowledge. In the chapter on Popper, I briefly compared Popper's conjecture-and-refutation mechanism with a Darwinian mutationand-selection mechanism in biology. A biological analogy can also be found in the case of Kuhn. During the 1970s, the biologists Stephen Jay Gould, Niles Eldredge, and others argued that the large-scale pattern seen in much biological evolution is "punctuated equilibrium" (Eldredge and Gould 197z). A lineage of organisms in evolutionary time will usually exhibit long periods of relative stasis, in which we see low-level tinkering but little change to fundamental structures. These periods of stasis or equilibrium are punctuated by occasional periods of much more rapid change in which new fundamental structures arise. (Note that "rapid" here means taking place in thousands of years rather than millions.) The rapid periods of change are disorderly and unpredictable when compared to the simplest kind of natural selection in large populations. The periods of stasis also feature a kind of "homeostasis" in which the genetic system in the population tends to resist substantial change.

  The analogy with Kuhns theory of science is striking. We have the same long periods of stability and resistance to change, punctuated by unpredictable, rapid change to fundamentals.

  The theory of punctuated equilibrium in biology was controversial for a time, especially because it was sometimes presented by Gould in rather radical forms (Gould 1980). The idea of a kind of "homeostatic" resistance to change brought about by the genetic system is a tendentious idea, for example. And the idea that ordinary processes of natural selection do not operate normally during the periods of rapid change, but are replaced by other kinds of processes, is also very unorthodox. But as the years have passed, the idea of punctuated equilibrium has been moderated and has passed, in its more moderate form, into mainstream biology's description of at least some patterns in evolution (Futuyma 1998).

  Gould also wrote a paper called "Eternal Metaphors in Paleontology" (1977), in which he argued that the history of theorizing about the history of life sees the same basic kinds of ideas about change come up again and again, often mixed and matched into new combinations. The analogy between Kuhns theory and the biological theory of punctuated equilibrium shows the same kind of convergence on a story about processes of change. We also see similar kinds of opposition between the "punctuated equilibrium" story found in Kuhn and Gould, on one side, and a more uniform, one-process view of change found in Popper and in some rival views of biological evolution, on another. I say "convergence" here, but Gould has acknowledged the influence of Kuhns picture of science on him when he was working out his biological ideas in the 196os and 1970s (Gould zooz, 967). Kuhn himself was also interested in (different) possible analogies between his picture of science and evolutionary change (1996, 171-7z).

  Further Reading

  The readings from chapter 5 are relevant here as well. For a very detailed discussion of Kuhn's philosophy, see HoyningenHuene 1993. Kitcher, The Advancement of Science (1993), contains thorough (and sometimes difficult) critical discussions of some of Kuhn's most influential arguments about revolutions and progress, including several aspects of the incommensurability problem. Kitcher also reanalyzes several of Kuhn's big historical examples. Doppelt 1978 is a clear discussion of incommensurability of standards.

  7.1 After Structure

  The period after the publication of Kuhns book was one of intense and sometimes heated discussion in all the fields that try to understand science. In this chapter we will discuss some other philosophical accounts of science developed around this time, all of them developed in interaction with Kuhn or in response to him.

  Then we will pause for a breath, and we'll consider some general patterns in the ideas described in the previous chapters.

  First, we will look at the views of Imre Lakatos. Lakatos's main contribution was the idea of a research program. A research program is similar to a paradigm in Kuhns (broad) sense, but it has a key difference: we expect to find more than one research program in a scientific field at any given time. The large-scale processes of scientific change should be understood as competition between research programs.

  It should be obvious from the previous chapters that this was an idea waiting to be developed. Kuhn's insistence that scientific fields usually have only one paradigm operating at any time was criticized right from the initial publication of Structure. Lakatos was the first person to develop a picture of science in which larger paradigm-like units operate in parallel and compete in an ongoing way. Lakatos's own development of this idea has problems, and it was embedded within a general philosophical program that has very peculiar features. Shortly after Lakatos's work, another philosopher, Larry Laudan, worked out a superior version of the same basic idea.

  After looking at Lakatos and Laudan, we turn to Paul Feyerabend, the wild man of twentiethcentury philosophy of science.

  Feyerabend is the most controversial and extreme figure contributing to the debates discussed in this book. I called him "the" wild man, even though there have been various other wild men-and wild women-in the field besides Feyerabend. But Feyerabend's voice in the debates was uniquely wild. He argued for "epistemological anarchism," a view in which rules of method and normal scientific behavior were to be replaced by a freewheeling attitude in which "anything goes."

  Kuhn, Lakatos, and Feyerabend all interacted and developed some of their ideas in response to each other (with the exception perhaps of much influence of Lakatos on Kuhn). Feyerabend's most important work (1975) was written, he said, as a kind of letter to Lakatos, but Lakatos died in 1974 before writing a reply.

  7.2 Lakatos and Research Programs

  Imre Lakatos had a remarkable life. Born in Hungary, he was a member of the resistance to Nazi occupation during World War II. After the war he worked in politics and was jailed for over three years by the Stalinist regime. He left Hungary, made his way to England, and eventually ended up at the London School of Economics working with Popper. Lakatos often claimed that his main ideas about science were implicit in Popper or were one side of Popper's views. Although there is some truth in this, it is better to consider Lakatos's ideas in their own terms.

  Lakatos's reaction to Kuhn's work was one of dismay. He saw Kuhn's influence as destructive-destructive of reason and ultimately dangerous to society. For Lakatos, Kuhn had presented scientific change as a fundamentally irrational process, a matter of "mob psychology" (1970, 178), a process where the loudest, most energetic, and most numerous voices would prevail regardless of reasons. The interpretation I gave of Kuhn in the previous two chapters is very different; in this interpretation Kuhn saw science as an almost miraculously well-structured machine for exploring the world. Even the disordered episodes found in revolutions have a positive role in the functioning of the whole. Lakatos, in contrast, saw the disorder in Kuhn's picture as no more than dangerous chaos. But Lakatos also saw the force of Kuhns historical arguments. So his project was to rescue the rationality of science from the damage Kuhn had done.

  Lakatos had some views about the relation between the history of science and the philosophy of science that are spectacularly strange. Lakatos argued that historical case studies should be used to assess philosophical views of science. Fine, so far. But he also said that we should write "rational reconstructions" of the historical episodes, in which scientists' decisions are made to look as rational as possible. We should then separately (or in footnotes) point out places where the rational reconstruction is not an accurate description of what actually went on. So it is OK to deliberately misrepresent what happened in the past, so long as the footnotes set things straight (see Lakatos 1970, 138 n, loo n). What matters most is that in the main discussion we are able to spin a story in which the scientific decisions come out looking rational. I have never understood why this idea is not met with more amazement and criticism from philosophers. (Hacking 1983 is a vigorous exception.)

  In among all this, however, Lakatos devel
oped a view of the organization of science that was very influential. This is known as his methodology of scientific research programs (though he spelled it "programmes," in the British way).

  A research program, for Lakatos, is roughly analogous to a Kuhnian paradigm (in the broad sense). The big difference, as I said above, is that there is usually more than one research program per field at any given time. According to Lakatos, competition between research programs is what we actually find in science, and it is also essential to rationality and progress. This view was applied to all of science, from physics to the social sciences.

  A research program is a historical entity; it evolves over time. It will contain a sequence of related theories. Later theories are developed in response to problems with the earlier ones. For Lakatos, as for Kuhn, it is common and justifiable for a research program to live for a while despite empirical anomalies and other problems. Workers within a research program typically have some commitment to the program; they do not reject the basic ideas of the program as soon as something goes wrong. Rather, they try to modify their theories to deal with the problem. However, for Lakatos as for Kuhn, research programs are sometimes abandoned. So a complete theory of scientific change must consider two different kinds of change: (z) change within individual research programs, and (z) change at the level of the collection of research programs within a scientific field.

  A research program has two main components, in Lakatos's view. First, it contains a hard core. This is a set of basic ideas that are essential to the research program. Second, a research program contains a protective belt. This is a set of less fundamental ideas that are used to apply the hard core to actual phenomena. The detailed, specific versions of a scientific theory that can actually be tested will contain ideas from the hard core combined with ideas from the protective belt.

  For example, the Newtonian research program of eighteenthcentury physics has Newton's three laws of motion and his gravitational law as its hard core. The protective belt of Newtonianism will change with time, and at any time it will contain detailed ideas about matter, a view about the structure of the universe, and mathematical tools used to link the hard core to real phenomena. The nineteenthcentury Darwinian research program in biology has a hard core that claims that different biological species are linked by descent and form a family tree (or perhaps a very small number of separate trees). Changes in biological species are due mostly to the accumulation of tiny variations favored by natural selection, with some other causes of evolution playing a secondary role. The protective belt of nineteenthcentury Darwinism is made up of a shifting set of more detailed ideas about which species are closely related to which; ideas about inheritance, variation, competition, and natural selection; ideas about the distribution of organisms around the earth; and so on.

  We now reach Lakatos's principles of scientific change. Let us first look at change within research programs. The first rule is that changes should only be made to the protective belt, never to the hard core. The second rule is that changes to the protective belt should be progressive. Here Lakatos borrowed from Popper's ideas. A progressive research program constantly expands its application to a larger and larger set of cases, or strives for a more precise treatment of the cases it presently covers. A progressive research program is one that is succeeding in increasing its predictive power. In contrast, a research program is degenerating if the changes that are being made to it only serve to cover existing problems and do not successfully extend the research program to new cases. Lakatos assumed, like Kuhn, that all research programs are faced with anomalies, unsolved empirical problems, at any time. A degenerating research program is one that is falling behind, or only barely keeping up, in its attempt to deal with anomalies. A progressive research program fends off refutation and also extends itself to cover new phenomena. Lakatos thought that, in principle, we could measure how quickly a research program is progressing.

  Now let us look at the higher level of change in Lakatos's system, change at the level of the collection of research programs present in a scientific field.

  Each field will have a collection of research programs at any given time, some of which are progressing rapidly, others progressing slowly, and others degenerating. You might be thinking that the next rule for Lakatos is obvious: "choose the most progressive research program." That would establish a decision procedure for scientists looking at their whole field, and it would give us a way of deciding who is making rational or irrational decisions. But that is not what Lakatos said.

  For Lakatos, it is acceptable to protect a research program for a while, during a period when it is degenerating. It might recover. This is even the case when another research program has overtaken it (Lakatos 1970. The history of science contains cases of research programs recovering from temporary bad periods. So a reasonable person can wait around and hope for a recovery. How long is it reasonable to wait? Lakatos does not say.

  Feyerabend swooped on this point (1975). For him it was the Achilles' heel in Lakatos's whole story. If Lakatos does not give us a rule for when a rational scientist should give up on one research program and switch to another, his account of rational theory choice is completely empty.

  So is there a third rule that tells us how to handle decisions between research programs? Not really. Lakatos did say that the decision to stay with a degenerating research program is a high-risk one (1971). So Lakatos might advise the rational scientist to stay with a degenerating research program only if he or she is willing to tolerate a high-risk situation. And Lakatos is right that different people can reasonably have very different attitudes toward risk. But Lakatos did not follow the suggestion up, to close the gap in his theory. The tremendous appearance of order and methodological strictness in Lakatos's philosophy of science is much undermined by his failure to say something definite about this crucial point. Feyerabend was right to see a mismatch between the rhetoric and the reality of Lakatos's views. Indeed, it sometimes looks as if the whole point of Lakatos's project was to give us a way of retrospectively describing episodes in science as rational.

  This is a good place to emphasize the vast difference between Lakatos and Kuhn in their underlying attitudes. Kuhn has a deep trust in the shared standards implicit in paradigms and the ability of science to find a way forward after crises, despite some groping and flailing along the way. For Kuhn, once we rid our picture of science of some myths, the picture we are left with is fundamentally healthy; Kuhn trusts science left in the hands of implicit shared values. Lakatos, in contrast, wants to have the whole enterprise guided by methodological rules-or at least he needs for us to be able to tell ourselves a story of that kind.

  Let us not worry further about the oddities in Lakatos's view. Instead, we can ask, Does his picture of the structure of science have any useful elements? Once we ask this, I think it is clear that the basic idea of competing research programs is a useful one. Certainly there are some fields where this seems a far more accurate description of what goes on than Kuhns paradigm-based view. Psychology is an obvious example. Current work in "evolutionary psychology" looks a lot like a research program in something like Lakatos's sense (Barkow, Cosmides, and Tooby 199z).

  We might also consider the possibility of mixtures of Kuhn-like and Lakatos-like stories. In biology, what we often find is consensus about very basic principles but competition between research programs at a slightly lower level. Looked at very broadly, evolutionary biology might contain something close to a single paradigm: the "synthetic theory," a combination of Darwinism and genetics. But at a lower level of generality, we seem to find competing research programs. The "neutral theory of molecular evolution" is a research program that tries to understand most variation and change at the molecular genetic level in terms of random processes rather than natural selection (Kimura 1983). This research program is compatible with the central claims of the synthetic theory, but it conflicts with some standard ways in which the synthetic theory is applied to genetic var
iation within populations.

  In the case of the neutral theory and also in other cases, what we find is a research program being "budded off" from the mainstream of biology and being explored for a few decades to see how much it can explain. Then it may turn out that the limits of the research program are reached, at which point it is moderated and folded back into the mainstream. That is what seems to be happening with the neutral theory.

  So we now have the tools for describing a range of different large-scale processes in science. Some fields may have dominant paradigms and Kuhnian normal science. Others may have competing research programs. Some might have very general paradigms plus lower-level research programs budding off periodically. (Here I should note that the term "research program" can also sometimes be used to describe different noncompeting approaches within a single field.)

  I have been discussing the usefulness of the research program idea in describing how science actually works. There is also the possibility of normative theories that make use of this concept. But I will not follow up that idea further within Lakatos's framework. We will return to the topic in the next section.