Natural kinds and ceteris paratis generalizations: In praise of hunches

According to stereotypical logical empiricist conceptions, scientific findings are approximately true (or perhaps true ceteris paribus) law-like generalizations used to predict natural phenomena. They are deployed using topic-neutral, generally reliable inferential principles like deductive or statistical inferences. Natural kinds are the kinds in such generalizations. Chemical examples show that such conceptions are seriously incomplete. Some important chemical generalizations are true often enough, even though not usually true, and they are applied using esoteric topic-and discipline-specific inference rules. Their important methodological role is to underwrite often-enough reliable, often socially implemented, scientifically informed guessing about chemical phenomena. Some chemical natural kinds earn their naturalness mainly from participating in such generalizations. These results generalize: many scientific generalizations, inference rules, and natural kinds function to inform guessing, that is, to underwrite the generation of hunches.