Abstract: How can intuitions be used to validate or invalidate a philosophical theory? An intuition about a case seems to be a basic evidential source for the truth of that intuition, i.e., for the truth of the claim that a particular example is or isn’t an instance of a philosophically interesting kind, concept, or predicate. A mental-state type is a basic evidential source only if its tokens reliably indicate the truth of their contents. The best way to account for intuitions being a basic evidential source is to interpret their subject matter in psychologistic terms. Intuitions provide evidence about the contents of the intuiter's concept, where “concept” is understood as a psychological structure.

Keywords: concepts, evidence, intuitional evidence, intuitions, philosophical theory,