Popper? I Don't Even Know Her! — Perry de Havilland of Samizdata quips in an aside that Karl Popper's conjectural objective epistemology “makes more sense” to him than Ayn Rand's epistemology. Well, Ayn Rand didn't really develop much of an epistemology (theory of knowledge). She developed the outline of a theory of concepts, and little else. In any case, the little bit of theory that she did produce has the virtue of coherence, while Popper's epistemology is grievously flawed.
According to Popper, prior to inquiry, the probability that all swans are white is zero. If I go out and observe a billion white swans, and no swans of other hues, then the probability that all swans are white is… still zero! The same as a contradiction!!! Popper claims that positive instances can do nothing to confirm a universal statement, which is just bizarre. Most large samples of a population match the population in composition. So of course finding something out about a large sample provides some evidence about the entire class.
Popper argues that one can only disconfirm a theory–prove that it is false. But then what do you say of a theory that has been subjected to huge numbers of potentially falsifying tests, but has passed with flying colors? Isn't not being falsified by many tests a lot like being confirmed? According to Popper, No! Then what's the difference between a theory that has passed a lot of tests, and a theory that hasn't been falsified because it's never been tested? Here, Popper just punts and makes up a different word for 'confirmation' and pretends to mean something different by it, similar to the way that Chomsky says we don't exactly “know” innate Universal Grammar, but we are “cognizant” of it.
Pace Popper, induction works just fine, and it works pretty much the way people intuitively think it does (i.e., The more horses you encounter, the surer your knowledge about horses in general.)
Anyway, for one of the most entertaining take downs in recent philosophy, try David Stove's Popper and After: Four Modern Irrationalists, which is conveniently online. The trashing of Popper starts right at the start of chapter one. Stove was a misogynist, racist, reactionary… but a good philosopher of science, and a damn fine writer. It's just blistering good fun.
Yes. I really care about this sort of thing.