It is around 50 years since Kuhn’s The Structure of Scientific Revolutions was published, and there have been retrospectives at various sites. I want to look at the retrospective in Scientific American, written by Gary Stix.
Stix begins with:
Scientific American’s review of Thomas Kuhn’s The Structure of Scientific Revolutions in 1964 ended with the pat pronouncement that the book was “much ado about very little.” The short piece, which appeared two years after the initial publication of Structure as a monograph in the International Encyclopedia of Unified Science, discarded as unoriginal Kuhn’s critique of the positivist argument that science progresses relentlessly forward toward the truth.
The reviewer’s glib dismissal missed the mark.
It is not all that clear to me that the reviewer missed the mark.
There are two groups of people who should have been interested in what Kuhn had to say. The scientists constitute one of those groups. The other group consists of philosophers, particularly philosophers of science. And those groups see Kuhn rather differently.
Kuhn’s thesis
I’ll start with a brief review of what Kuhn was arguing.
Kuhn distinguished between what happens in scientific revolutions, and what happens in what he called “normal science.” He looked to examples from the history of science to illustrate the point. Perhaps the Copernican revolution (the change from geocentrism to heliocentrism) and relativity (Einstein’s replacement for Newtonian mechanics) were the two most important revolutions that he examined. Kuhn argued that while normal science is gradual and progressive, revolutionary science brings upheaval, and big changes in how scientists do things – he use the term “paradigm shift” for those changes. In particular, a paradigm shift brought with it a change in concepts and a change in laws. Those changes can be quite dramatic. This led Kuhn to suggest that science is not progressive, at least during revolutions, and that there can be a problem of incommensurability between the concepts of the older theory and the concepts of the newer theory.
How scientists see Kuhn
I suppose that the way I look at it is within the range of how scientists do. I found Kuhn’s thesis interesting but hardly earth shaking. As best I can tell most scientists, or at least most physicists, look at it in much the same way.
I look at both the Copernican revolution and the changes due to Einstein’s relativity as progressive and important. I don’t see the incommensurability as a big problem. Even today, Newtonian mechanics is much used, and scientists don’t seem to have a problem switching between Newtonian mechanics and relativistic mechanics, depending on their needs. The reason Newtonian mechanics are still used is that they are far easier to use (simpler equations), and that the practical differences between Newtonian and relativistic mechanics are often too small to matter. The differences become large only for motion at high velocity or for very intense gravitation.
When Stix says “The reviewer’s glib dismissal missed the mark”, it seems to me that the 1964 reviewer was expressing a viewpoint typical of that of scientists, and the viewpoint that scientist should indeed have held.
The view from philosophy
Philosophers did seem to see Kuhn’s thesis as challenging. The view of some seems to be that Einstein demonstrated that Newton was wrong, that Newtonian science had been falsified.
Why the difference?
Philosophers and scientists look at things very differently. As I suggested in an earlier post, scientists tend to view their theories semantically, while philosophers tend to view them syntactically.
Comparing relativity to Newtonian mechanics, we see that the basic laws are significantly changed. But the basic concepts are also changed. If we factor the change in laws through the changes in concepts in order to see what they say about reality, then the change from Newton to Einstein is really quite small. And that’s the semantic way of looking at the laws, the way scientists tend to see them. If we look at it syntactically, if we look only at the change in laws and disregard the change in concepts, then the switch from Newton to Einstein appears far more dramatic. And that’s the view that philosophers seem to follow.
I am not sure how philosophers see change in concepts. I have tried discussing this with two philosophers. The first just shrugged his shoulders and seemed to think it not important. The second tried to explain why he saw the conceptual change as not important. As best I could tell, he was taking the concepts as fixed by metaphysics, and therefore they could not be changed. Perhaps Newton got them slightly wrong, and the conceptual changes from Einstein were just a matter of correcting those mistakes by Newton.
Back to the interview
In the Scientific American article, Stix is interviewing Ian Hacking. In reply to a question, Hacking says:
Both Kuhn and Popper [Karl Popper, the philosopher] were deeply influenced by these changes and then later moved on to the idea that they were extreme examples of something that would be happening quite commonly in the sciences. There was a tendency for them to generalize from these epoch-making changes in a way that is less appropriate today.
Now it is Hacking who seems to be taking a dismissive attitude toward Kuhn’s ideas. That’s unfortunate. Kuhn’s ideas were addressed to philosophers, and it is they rather than the scientists who should have been influenced by Kuhn. Hacking’s response suggests that Kuhn’s influence is wearing off.
Stix: How has the rise of biology changed the dynamics of doing science since Kuhn’s time?
Hacking: So much work in the contemporary life sciences is much less theory driven and much more technique driven than was the case for physics, which was Kuhn’s science 50 years ago.
Perhaps Hacking equates theory with the use of mathematics. And it is true that biology is less mathematical than physics. Yet it is also more mathematical that it was 50 years ago.
I think Hacking is looking at this the wrong way. What I took to be the important part of Kuhn’s thesis, was his emphasis on conceptual change. Whenever biologists identify a new species, that introduces a new concept into the language. It should be considered a conceptual change. Likewise, the endosymbiosis thesis of Lynn Margulis introduced a major conceptual change.
Those changes were perhaps not revolutionary. The conceptual changes could be absorbed within the existing framework that guides research in biology. The scientific revolutions occur only when the conceptual changes stretch the existing framework beyond what it can bear, and that’s what leads to paradigm shift. But, whether or not there is a paradigm shift, it is conceptual change, and not merely the accumulation of facts, that drives science.
The Heretical Philosopher 