Throughout his mature writings, Berkeley speaks of minds as substances that underlie or support ideas. After initially flirting with a Humean account, according to which minds are nothing but ‘congeries of Perceptions’, Berkeley went on to claim that a mind is a ‘perceiving, active being... entirely distinct’ from its ideas. Despite his immaterialism, Berkeley retains the traditional category of substance and gives it pride of place in his ontology. Ideas, by contrast, are ‘fleeting and dependent beings’ that must be supported (...) by a mental substance. There is no doubt that Berkeley’s conception of the relationship between minds and ideas is non-traditional, but that fact does not undercut his commitment to the traditional conception of substance. A robust literature has grown up around the thorny issue of reconciling Berkeley’s endorsement of mental substance with his rejection of its material counterpart. (shrink)