(The following is an imaginary scenario in which TS Kuhn and Sir Karl Popper are each asked to
explain their views of science in a nutshell for a non-technical audience. First Kuhn recounts his book The Structure of Scientific Revolutions (1962), and then admits (as he actually did in later life) that he may have exaggerated the extent and nature of the relativism for which he argued in that book. He is followed by Karl Popper defending the claim that scientific knowledge is cumulative in that over time our body of scientific knowledge becomes greater in scope and explanatory power. These are thumbnail sketches, and not complete summaries of the detailed work of these two difficult philosophers. But as a basic overview, hopefully it captures some of the important differences between these two giants in the philosophy of science. There is a fairly short tutorial video attached below which summarizes the main points of each philosopher's model of the natural sciences.)
TS Kuhn:
"Theories should not be imagined as part of a long-term progression from ignorance to Truth with a capital "T." Rather, when scientific theories change they change the meanings of basic terms like time,space, mass, energy, gravity and so on. To say that we have "progressed" from Newtonian mechanics to Einsteinian General Relativity suggests that there is something basic at the heart of Newton's theory, or a set of basic properties at its heart, that have survived the transition into Einsteinian physics (and later Quantum physics as well). Absolute space and time, the equation for gravity and the corpuscular theory of light,among other fundamental components, haven't survived.
When scientists conceptualize the universe *after* a"paradigm shift" from one theory to another, they are not really conceptualizing the same world. Terms like time, space, mass, energy and others may sound the same and be spelled the same way-- but they don't refer to the same concepts or even the same entities (for example no one refers seriously to such entities as "ether"--a hypothetical substance through which light was thought to travel not too long ago, and other examples like "phlogiston" come to mind readily). In my early work I suggested that if someone living in Newton's time had a discussion with an Einsteinian physicist, they would suffer communication failure because of the radically different worldviews each theory entails. To use a cliche, they would be talking "apples and oranges." I referred to this radical and extreme version of conceptual relativism as the problem of "incommensurability." Much ink has been spilled on the matter since then,with some critics saying I went too far imagining such problems, while the argument convinced others that all observations and statements are theory-laden down to the core--i.e. that theories are like the lenses of sunglasses which change the your perception of the world. If I'm wearing Newtonian lenses and you are wearing Einsteinian ones we can't have a reasonable chat about the universe because we're looking through different conceptual filters which color the universe itself in drastically different ways. Ultimately, the strongest form of this view leads to the conclusion that in some meaningful way, we are all prisoners of paradigms which structure our conceptions of reality for us in advance. I may have exaggerated the point, but unlike Karl, I hold that working scientists do not really busy themselves trying to refute the very theories their own routine work presupposes. On the contrary, they generally take the theories that they were taught more or less for granted. The theoretical status quo tends to shape perceptions, expectations and cognition for working scientists. Unless they have very strong reasons for doubting the knowledge they learned at University, they will view the theory within which they are working as being non-problematic. This enables them to get on with their researches, solving puzzles that come up in their everyday work. I call this typical mode of scientific understanding "Normal Science," because it is most typical of scientific work, while theory changes (paradigm shifts) only occur once in a great while.
When paradigms do shift it is because of a large number of anomolies (unexpected results which run counter to the predictions of prevailing theories and hypotheses) which at some point make the theory appear implausible. This state of implausibility in which there is no normative framework for the science in question I term crisis and it culminates, after a time, in a new paradigm or framework which accounts for the anomolies or irregularities that led to the crisis. Thus the old paradigms/theories are "overthrown" in a "Revolutionary" phase during which new ones are formed and legitimated (I admit to a weakness for political metaphors.) By the time the new theory is accepted as a "Paradigm" that can be taken for granted as valid, it will be as "incommensurable" with the old theory as that one was with the former one and so on. My conclusion--and I stand by it-- is that there is no progress to speak of in science since each theory is non-continuous with its predecessors and its successors. This, in a nutshell, is what I tried to show as an historian of science in the 1960s."
Sir Karl Popper's Response: "In point of fact, though, you showed no such thing! Oh, of course, there is some truth in the historical analysis and examples you provide, but these merely *slow down* the growth of knowledge, they do not create all the catastrophic difficulties you imagine! If you set the bar for a successful theory too high, you might be led to some of the conclusions you reached. But if instead of expecting absolute certainty, you view science as an ongoing attempt to SOLVE PROBLEMS that arise in empirical work by advancing *conjectures* or *tentative theories* you will see that in the long run knowledge is additive, though mistakes are made, and progress is not linear. Imagine that in the course of trying to solve a difficult problem in science, a tentative theory is advanced. If it is a good theory it will survive without being *falsified* or refuted despite repeated attempts to do so within the scientific community. We are fallible, of course, but we may treat theories that have survived repeated attempts at falsification as *provisionally true*. We must remember that as scientists we are all fallible, we might be wrong about something at any time without even knowing it at that time. But over the long run, those conjectures or tentative theories which are not falsified survive, adding knowledge that survives with them even as some terms get tweaked or redefined. I sometimes liken this process to biological evolution where organisms best fitted to the environment tend to survive over the long run, on average, while those ill-suited to the environment tend to get winnowed out. If we look at the growth of knowledge that way, there is a long-term self-correcting mechanism which tends to insure that theories better fitted to empirical realities survive, while those marred by error are eliminated by an eventual process of falsification (this needn't be one, but more likely several falsifying results and close investigations into possible explanations other than that of a flawed theory). Those theories which are most successful have a time honored record of predicting empirical outcomes and surviving attempts at refutation. These may not constitute knowledge of the world that is True in some ultimate metaphysical way, since we are fallible, but clearly the fact that our ability to predict and control outcomes is so good indicates that the scientific process does generate knowledge of the empirical world. What survives from one era to the next, one theory to the next, are the predictive statements and hypotheses that do not get falsified. If and when they are falsified in a systematic way we must give up our pet theories and formulate new conjectures in the hope that they will not be disconfirmed. Indeed, if we look at the transition from Newton to Einstein in that light, then it is apparent that we can make more unfalsified predictions about empirical outcomes now than in the Newtonian era. By my lights this counts as progress which is hard won through the rigorous empirical methodology of conjecture and refutation.
As for you and your epistemological despair, I think you should have a martini and settle down,
Thomas. And don't let all those book sales go to your head! Your more extreme conclusions simply do not follow from your own premises."
Note:
Working scientists rarely worry about Kuhn's relativism or the possibility that they are not studying the "real world" as it is, but only as it appears from within their "paradigms." They have not debated or answered Kuhn as philosophers do. Instead they simply ignore it as irrelevant to their actual work. However, in philosophy OF science, Kuhn has more or less set the agenda for discussions of science which have centered on questions of relativism, realism (can we know how the world "really" is in itself, beyond our own perspectives and theories?), and the nature of theory change. If I were pressed to make a generalization, I'd say that Popper has widely influenced the practice of empirical science while Kuhn has widely influenced the philosophical interpretation of that science.
It has also been noted (for example by the philosophy professor speaking in the below video) that social scientists have given Kuhn a much warmer reception than natural scientists (chemistry, biology, physics etc.)
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So what do you think? Sir Karl Popper or Professor Kuhn?
Some possible combination? Perhaps neither? What's your point of view?
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