Popper and Synthetic judgements A Priori

Summary  Popper uses the “Humean challenge” as a justification for his falsificationism. It is claimed that in his basic argument he confuses two different doubts: (a) the Humean doubt (Popper’s problem of induction), and (b) the “Popperean” doubt whether – presupposing that there are laws of nature – the laws we accept are in fact valid. Popper’s alleged solution of the problem of induction does not solve the problem in a straightforward way (as Levison and Salmon have remarked before). But if Popper’s solution of the Humean challenge is re-interpreted as being close to Kant’s it makes sense. Even though Popper explicitly rejects Kant’s synthetic judgements a priori, it is claimed here that this is so because he misinterprets Kant’s argument. If he had understood Kant correctly he should have been a modern “Kantianer”!