 Kripke (1972/1980) suggests that our knowledge of some other essentialist claims is based in part on a bit of a priori knowledge and in part on a bit of empirical knowledge. For example, our knowledge that originating from \(s\) and \(e\) is essential to Socrates is based in part on our a priori knowledge that every organism has its origin essentially and in part on our empirical knowledge that Socrates (is an organism that) originated from \(s\) and \(e\). (Similarly our knowledge that Socrates is essentially human appears to be based in part on our a priori knowledge that everything has its kind essentially and in part on our empirical knowledge that Socrates is (of the kind) human.) Thus, our knowledge of the claim that originating from \(s\) and \(e\) is essential to Socrates should be no more problematic epistemologically than our knowledge of the two claims on which it is based and our knowledge of the validity of the argument from those two claims. As we have already mentioned, although there are difficult philosophical issues concerning our knowledge of logical truths, our knowledge of the validity of the argument in question does not seem to add any special problems of its own. Similarly, although there are philosophical issues concerning empirical knowledge, our knowledge that Socrates originated from \(s\) and \(e\) does not appear to add any special problems. However our a priori knowledge that every organism has its origin essentially does seem to have special problems over and above the problems associated with accounting for our a priori knowledge of logic, mathematics, and the homelier necessary truths. The latter claims are generally supported by universally held intuitions or by arguments that are universally accepted whereas the former, like most philosophical claims, is supported by a less robust intuition and by a more controversial argument. To see in some detail how philosophers have gone about defending origin essentialism, see the