Locke on the idea of substratum

Locke's treatment of substratum is notoriously difficult. According to one commentator, nothing else in the writings of any philosopher matches the do ubleness of attitude of the passages about substratum in Locke's Essay (Ben nett 1987, 197). The aim of the present paper is to render consistent Locke 's seemingly divergent strands on the subject. My efforts are organized aro und three levels of apparent duplicity. At each level, I argue that the dou bleness of attitude in Locke's treatment is merely apparent. I argue furthe r that Locke means to ground an empiricist-friendly idea of substratum in t he customary experience of simple ideas that go constantly together.