 Locke's reaction was in many ways typical of the general tenor of post-scholastic rejections of substantial form in that he founded his charges of unintelligibility largely on epistemic considerations: the fruitlessness of substantial forms, he thinks, is shown most readily by their empirical inadequacy. We have, he complains, no experience of them at all, and therefore, no idea of what we might be taking ourselves to be positing. This is in part because Locke conflates the notion of substance with that of substratum, which he derides as a something “I know not what, [introduced] to support those ideas we call accidents” (Locke 1976 [1690]: 2.23.15).