Popper vs Kuhn

There aren't a lot of differences in the picture of science presented by Karl Popper and Thomas Kuhn, provided that we view Popper's philosophy with the refinements proposed by Imre Lakatos, and that we row back on Kuhn's concepts of incommensurability and theory-ladeness of data.

However, there remains a very important difference of spirit between these two philosophies, a difference that is reflective of two opposing philosophical attitudes towards science.

This difference is explained very well by Bruce in a blogpost on Wheat and Tares:

"... unlike Popper, Kuhn latches on to the non-teleological (i.e. non-purposeful) nature of evolution as his main thesis....

[Kuhn] suggests that scientific progress is a non-teleological process, just like organic evolution. That is to say, the growth of scientific knowledge (which Kuhn does believe in) is not a growth towards some underlying reality, but merely a growth of solved problems that we humans found interesting.

This, then, is the primary difference between Kuhn and Popper – and it’s a huge difference in my opinion: Kuhn is a Positivist and Popper is a Scientific Realist. Popper believes that there is an underlying reality that we can grow closer to whereas Kuhn does not believe this is necessary to explain scientific progress."

I do not know how justifiably one can call Kuhn a Positivist, but apart from that, the difference between Kuhn and Popper is articulated very well. For Popper the progress of science is a progress in direction of reality, such that each successive theory (or to use Kuhn's better term 'paradigm shift') brings us closer to truth. But for Kuhn, the progress of science has no direction. Each paradigm shift bears no relation to our proximity to truth; we might as well be moving away from it.

In Popper vs Kuhn, I am with Popper.


Qasim Aziz said…
I have absolutely no clue how can one categories Kuhn as a positivist. However, coming back to this brilliant blog post.

Here are a few reservations.
I think for me Popper will regard any new scientific theory not a move closer to truth(truth with capital T) but rather a move away from falsehood or mistake. A subtle difference but still very relevant in understanding Popper's argument. I can substantiate this interpretation by summing up Popper's argument from another philosophical work 'The Open Society and its enemies'(by no means a work of philosophy of science but sums up Popper's attitude towards all kind of historicism and teleology). Popper argued vehemently in that book against teleological approach of Hegel, Aristotle, Marx and Plato for holding a view of reality (truth) based on purpose (telos). However, this critique does not mean that Popper is a relativist. Let me rephrase what I said, as per Popper it is not scientifically possible to talk about the absolute truth but we can always recognize falsehood. Since for Popper science thrives on falsification, there is always room for absolute truth (in abnon-demonstrable way).

The difference between Popper and Kuhn for me lies here. Popper despite being skeptic about teleological theories of all kind held a vision of science based on 'demarcation'. By demarcation I mean that Popper genuinely believed that the scientific method is distinct from non-science. Hence his emphasis on 'falsification' as the dividing line between science and non-science. However, for Kuhn science is not a disinterested and cold inquiry about the nature of reality. In fact, scientists are no different from priests who dogmatically promote their own denominational theologies (only making sense within their own paradigms).

This relativism is exactly what disturbed Popper back in 1960s. Kuhn's understanding of 'normal science' was a threat to future of science according to Karl Popper. The famous 1965 International Colloquium was called by Popper in order to destroy this idea of Kuhn.
F. said…
Science for Science's sake?
Sounds a lot like Art.
Awais Aftab said…
Some supporting material from Stanford Encyclopedia of Philosophy entries on Popper and Kuhn.


* Popper was initially uneasy with the concept of truth, and in his earliest writings he avoided asserting that a theory which is corroborated is true—for clearly if every theory is an open-ended hypothesis, as he maintains, then ipso facto it has to be at least potentially false. For this reason Popper restricted himself to the contention that a theory which is falsified is false and is known to be such, and that a theory which replaces a falsified theory (because it has a higher empirical content than the latter, and explains what has falsified it) is a ‘better theory’ than its predecessor. However, he came to accept Tarski's reformulation of the correspondence theory of truth, and in Conjectures and Refutations (1963) he integrated the concepts of truth and content to frame the metalogical concept of ‘truthlikeness’ or ‘verisimilitude’. A ‘good’ scientific theory, Popper thus argued, has a higher level of verisimilitude than its rivals, and he explicated this concept by reference to the logical consequences of theories.

* Thus scientific progress involves, on this view, the abandonment of partially true, but falsified, theories, for theories with a higher level of verisimilitude, i.e., which approach more closely to the truth. In this way, verisimilitude allowed Popper to mitigate what many saw as the pessimism of an anti-inductivist philosophy of science which held that most, if not all scientific theories are false, and that a true theory, even if discovered, could not be known to be such. With the introduction of the new concept, Popper was able to represent this as an essentially optimistic position in terms of which we can legitimately be said to have reason to believe that science makes progress towards the truth through the falsification and corroboration of theories. Scientific progress, in other words, could now be represented as progress towards the truth, and experimental corroboration could be seen an indicator of verisimilitude.


* Kuhn also, for the first time, explicitly gave his work an anti-realist element by denying the coherence of the idea that theories could be regarded as more or less close to the truth.

* Kuhn is quick to deny that there is any inference from such increases to improved nearness to the truth ((1962/1970a, 170–1). Indeed he later denies that any sense can be made of the notion of nearness to the truth (1970a, 206).

* Hence incommensurability is supposed to rule out convergent realism, the view that science shows ever improving approximation to the truth. (Kuhn also thinks, for independent reasons, that the very ideas of matching the truth and similarity to the truth are incoherent (1970a, 206).)