 Though foundationalism brilliantly allows for the expansion of knowledge from first principles, Descartes thinks that a complementary method is needed to help us discover genuine first principles. As Hatfield writes, “the problem is not to carry out proofs (which might well be assented to, given the definitions and axioms), but to discover the axioms themselves (which are hopelessly obscured by the prejudices of the senses)” (1986, 71). Descartes therefore devises the method of doubt for this purpose – a method to help “set aside” preconceived opinions.