Kuhn 4: What Is "Normal" Science?
Jan. 25th, 2009 06:35 pm![[personal profile]](https://www.dreamwidth.org/img/silk/identity/user.png)
Further guidance for reading Thomas Kuhn's essay "What Are Scientific Revolutions?" which you can find complete here, pp 13 to 32. I'd say try to finish the essay by Tuesday, which is when we'll start talking about it unfettered, though if you've got questions and quotations to post before then, feel free to do so in the comments.
You could say that "scientific revolution," "paradigm shift," and "incommensurability" are mutually defining: Q: When is a change in a scientific discipline enough to be considered a revolution? A: When the change involves a paradigm shift. Q: What's a paradigm shift? A: A paradigm shift occurs when a set of interrelated concepts and terms and theories are replaced by a different set of interrelated concepts etc. that are incommensurable with the first. Q: In what sense are these sets incommensurable? A: The sets are incommensurable when the difference between the new and the old is so revolutionary that there's no way to map new concepts etc. onto the old or vice versa in a way that would make the resulting science intelligible.
OK, but must the fact that there are paradigm shifts necessarily mean that there are periods of scientific "revolution"? I think that Aristotle's concept of motion is unquestionably "incommensurable" with Newtonian physics (as Kuhn is using the term "incommensurable"), and if you were trained in one you'd have to shift paradigms to understand the other. But Newton and Aristotle lived a couple of millennia apart. So, placing Aristotle right next to Newton, you see a revolution-sized gap, but couldn't that gap be due to the accumulation of a lot of small evolutionary adjustments over 2,000 years? Imagine that the earth undergoes a lot of tiny tectonic shifts and readjustments but never has an earthquake; nonetheless the tectonic plates could have moved the same distance over a period of time that they would have were there periods of little movement interrupted by large earthquakes.
Similarly, the alternative to there being scientific revolutions would be that words and concepts and theories are always being contested in little ways and are always being adjusted in the face of anomalies and difficulties. So over time you get the same "incommensurability" that Kuhn observes, the same holistic and noncumulative change (noncumulative in that, e.g., later scientists didn't merely build on Aristotle's achievements: some of his core concepts disappeared and were supplanted by other concepts). And intellectuals who want to get all excited or upset by incommensurability and theory-dependent facts and such still have something to get excited or upset by. But we don't necessarily have to have periods of "normal" science (i.e., nonrevolutionary science) interspersed with periods of "revolutionary" science. We can have evolution rather than revolution, little shifts always happening rather than periods of no shifts interspersed with periods of big shifts. We can say that yes, some of the evolution happens more suddenly and in bigger increments than others - a big one would be Copernicus deciding in the early 16th century that earth was a planet or Ehrenfest and Einstein independently figuring out in 1906 that it is impossible to derive Planck's black-body law without positing discontinuous energy, i.e. energy jumping from level to level rather than increasing or decreasing continuously - but overall, big or small, the shifts and adjustments in language, concept, and theory never stop happening.
Whereas Kuhn is arguing that we get periods of "normal science" during which a field undergoes "normal change" and that we get contrasting periods of "revolutionary change." In "normal change," none of the major terms and concepts are being contested, scientists solve problems by applying the (small-p) paradigms they've got to new situations, and change is cumulative in that it builds on the work of predecessors rather than overthrowing some of that work. A revolutionary period of change is where paradigms compete with one another, scientists are creating new concepts and models, but no set of concepts has achieved enough coherence to take over the field yet. So Copernicus and Planck/Einstein/Ehrenfest changed the way their respective games were played, the language and concepts going into years of significant flux and not coming to rest until words, concepts, theories etc. were integrated into a largely coherent whole - after which, normal science returned, using new concepts and models.
Despite its name, I want us to think of Kuhn's idea that there is "normal change" and "normal science" as strange and challenging. We should ask: (1) Does normal science as Kuhn conceives it actually exist? (2) If it does exist, does the equivalent exist anywhere other than in science? --I'll say flatly that it sure doesn't seem to exist in music criticism or in art. What's normal in science may not be normal elsewhere.
In thinking about what Kuhn means by "normal science," get rid of the idea of a majority versus a minority, a dominant (big-p) paradigm* versus marginal ones, the dominant one being the one that a majority or a strong plurality of people in the field adhere to. Rather, think of everyone in the field working within the dominant paradigm (though this doesn't mean that there can't be failed "revolutions," where someone tries to make a major conceptual switch and it doesn't catch hold).
*Remember that "paradigm" has two meanings: it can be a specific model and it can be an overall practice. I'm distinguishing them by calling the former a "small-p paradigm" and the latter a "big-p paradigm."
You could say that "scientific revolution," "paradigm shift," and "incommensurability" are mutually defining: Q: When is a change in a scientific discipline enough to be considered a revolution? A: When the change involves a paradigm shift. Q: What's a paradigm shift? A: A paradigm shift occurs when a set of interrelated concepts and terms and theories are replaced by a different set of interrelated concepts etc. that are incommensurable with the first. Q: In what sense are these sets incommensurable? A: The sets are incommensurable when the difference between the new and the old is so revolutionary that there's no way to map new concepts etc. onto the old or vice versa in a way that would make the resulting science intelligible.
OK, but must the fact that there are paradigm shifts necessarily mean that there are periods of scientific "revolution"? I think that Aristotle's concept of motion is unquestionably "incommensurable" with Newtonian physics (as Kuhn is using the term "incommensurable"), and if you were trained in one you'd have to shift paradigms to understand the other. But Newton and Aristotle lived a couple of millennia apart. So, placing Aristotle right next to Newton, you see a revolution-sized gap, but couldn't that gap be due to the accumulation of a lot of small evolutionary adjustments over 2,000 years? Imagine that the earth undergoes a lot of tiny tectonic shifts and readjustments but never has an earthquake; nonetheless the tectonic plates could have moved the same distance over a period of time that they would have were there periods of little movement interrupted by large earthquakes.
Similarly, the alternative to there being scientific revolutions would be that words and concepts and theories are always being contested in little ways and are always being adjusted in the face of anomalies and difficulties. So over time you get the same "incommensurability" that Kuhn observes, the same holistic and noncumulative change (noncumulative in that, e.g., later scientists didn't merely build on Aristotle's achievements: some of his core concepts disappeared and were supplanted by other concepts). And intellectuals who want to get all excited or upset by incommensurability and theory-dependent facts and such still have something to get excited or upset by. But we don't necessarily have to have periods of "normal" science (i.e., nonrevolutionary science) interspersed with periods of "revolutionary" science. We can have evolution rather than revolution, little shifts always happening rather than periods of no shifts interspersed with periods of big shifts. We can say that yes, some of the evolution happens more suddenly and in bigger increments than others - a big one would be Copernicus deciding in the early 16th century that earth was a planet or Ehrenfest and Einstein independently figuring out in 1906 that it is impossible to derive Planck's black-body law without positing discontinuous energy, i.e. energy jumping from level to level rather than increasing or decreasing continuously - but overall, big or small, the shifts and adjustments in language, concept, and theory never stop happening.
Whereas Kuhn is arguing that we get periods of "normal science" during which a field undergoes "normal change" and that we get contrasting periods of "revolutionary change." In "normal change," none of the major terms and concepts are being contested, scientists solve problems by applying the (small-p) paradigms they've got to new situations, and change is cumulative in that it builds on the work of predecessors rather than overthrowing some of that work. A revolutionary period of change is where paradigms compete with one another, scientists are creating new concepts and models, but no set of concepts has achieved enough coherence to take over the field yet. So Copernicus and Planck/Einstein/Ehrenfest changed the way their respective games were played, the language and concepts going into years of significant flux and not coming to rest until words, concepts, theories etc. were integrated into a largely coherent whole - after which, normal science returned, using new concepts and models.
Despite its name, I want us to think of Kuhn's idea that there is "normal change" and "normal science" as strange and challenging. We should ask: (1) Does normal science as Kuhn conceives it actually exist? (2) If it does exist, does the equivalent exist anywhere other than in science? --I'll say flatly that it sure doesn't seem to exist in music criticism or in art. What's normal in science may not be normal elsewhere.
In thinking about what Kuhn means by "normal science," get rid of the idea of a majority versus a minority, a dominant (big-p) paradigm* versus marginal ones, the dominant one being the one that a majority or a strong plurality of people in the field adhere to. Rather, think of everyone in the field working within the dominant paradigm (though this doesn't mean that there can't be failed "revolutions," where someone tries to make a major conceptual switch and it doesn't catch hold).
*Remember that "paradigm" has two meanings: it can be a specific model and it can be an overall practice. I'm distinguishing them by calling the former a "small-p paradigm" and the latter a "big-p paradigm."