Thomas Kuhn writes that: “In so far as (scientists) only recourse to (the) world (of their research) is through what they see and do, we may want to say that after a revolution scientists are responding to a different world.” (SSR, 111) The question becomes: in what way does Kuhn mean this statement, as purely factual or merely metaphorical? To begin with one must take note of a statement he makes later in the same section, “… the scientist after a revolution is still looking at the same world.” (129) So, it is safe to say that Kuhn is a realist of some sort. That is he believes that the world exists in its actuality autonomous of human cognition. The point then becomes how one accesses this world. For Kuhn science always functions within paradigms. The student of science is not only trained into the tradition of science but into a certain way of conceptualizing and carrying out that very tradition, i.e. into a paradigm. Because paradigm’s provide the ontological coordinates for the way the world is, the student/scientist has no access to the world outside of a paradigm. This is how gestalt switches in scientific paradigms differ from gestalt switches in other arenas.
In the example of a gestalt switch present when a series of lines appears as at one time a duck and at another a rabbit the subject can eventually gain access to the lines themselves by piercing through these switches into the lines that are their substrate. She can step back, as it were, from the experiment and say that both ways of viewing it are wrong, or at least only partially right. (114) While this is the case with many psychological experiments, when it comes to scientific observation this is not so. Why?
To understand this one must start with the fact that, “… neither scientists nor laymen learn to see the world piecemeal or item by item…” but rather, as Kuhn points out, “(both) sort out whole areas together from the flux of experience.” (128) The world in its autonomy is not accessible to observation except through a paradigm and a paradigm constitutes a web of beliefs in which all items are interconnected in such a way that the change of one constitutes a change in all relative to their theoretical proximity to the change. The convert to Lavoisier’s theory does not say, “there is some thing out there that is involved in a process that I call fire. I used to think it was an element called phlogiston that behaves a certain way, but now I think it has something to do with a substance I call oxygen, which behaves very differently.” Rather, he says something like, “I used to think that phlogiston existed and helped explain combustion but now I realize that I was wrong and that oxygen is what I used to think of as dephlogisticated air. Further, I have had to realign my understanding of combustion so that it is the chemical combination of a substance with oxygen, instead of phlogiston being used up.”
The world after Lavoisier is a different world—it has no phlogiston, fire is different, etc.—then that of Priestly. However, it is not a different world qua world in itself, but rather for the scientist. Yet, in so far as the scientist’s only recourse to this world in itself is through what she sees and does, and in so far as what she sees and does is made possible and thus determined by her paradigm, one can say that after a revolution she is living in a different world. The unique mode of human existence qua scientific research of the world is, for Kuhn, such that there is no way of stepping back from the picture, i.e. flux of the world as perceived through a paradigm, and perceiving the lines that make up one picture verses the other. The only way to perceive the picture at all through scientific research is either as a duck or a rabbit. As Kuhn says, “The alternative is not some hypothetical “fixed” vision, but vision through another paradigm…” (128)
As this point one may be tempted to say that, “what changes with a paradigm is only the scientist’s interpretation of observations that are themselves fixed once and for all by the nature of the environment and of the perceptual apparatus.” (120) However, for Kuhn this would be a mistake. The first problem is that observations are not fixed. Kuhn stresses the point that observations are not mere sensory perceptions. Instead they themselves require a paradigm. As an example he points out that the Chinese were able to record the appearance of many new stars in the heavens before the West. This was not due to more sophisticated observational apparatuses, which the Chinese didn’t have, but rather to the fact that their paradigm allowed for celestial change. In the West change was not perceived in the heavens until the half century after Copernicus. (116) Kuhn suggests that the observations themselves are only observable within a paradigm because it is only within a paradigm that they appear at all.
This is connected to the idea of a fixed perceptual apparatus, which is another of Kuhn’s problems with this statement. Kuhn, again, seeks to stress the fact that the perceptual apparatuses that are used to gather observations within a paradigm are themselves determined by that paradigm. The paradigm tells them what to look for and how to look. (126) This is related to the previous idea of the flux of experience. Paradigm’s help the scientist to sort out the flux, fixing certain areas and processes which are important to his or her work so that they can be accessed in ways which will prove fruitful for the scientific paradigm. These reasons point to Kuhn’s suggestion that instead of being an interpreter the scientist inhabiting a new paradigm is like the man wearing inverted lenses. He confronts the same world but finds that it is entirely different through and through. (122)
I am content with Kuhn’s response, at least as it is understood contextually. He seems to be suggesting that within science there is no direct access to the Real, i.e. the world in itself, but rather that all access is mediated. Further, since there is no recourse to the Real, via science, all one can say is that in a very real way the world itself changes as science does. I have pointed out that I read Kuhn as still an ontological realist. My one question would be is there a possibility of accessing the Real for human beings at all? That is, what epistemological criterion must be met in order to have genuine knowledge as justified true belief? Kuhn, suggests that, at least for science, there is not some “hypothetical fixed nature” that is accessible. (124) (It is hard to know how to read this statement itself—is Kuhn here flirting with Idealism?—but I have chosen to read it as somewhat hyperbolic in light of other statements he makes which suggest some type of realism.) Yet, one may ask, would this be the only way to approach the Real, or is another way possible? Is there an epistemology that can take into account the relative success of the sciences and work itself out from there?