ABSTRACT
The theory that a human mind is an immaterial substance is held by many early modern thinkers, although by no means all. Because the natural immortality of the soul is at stake, the thesis is fraught with religious and moral significance. But this article is concerned with the psychological and metaphysical issues it raises. Plato and Augustine advocate the immateriality and substantiality of the human soul, and even Aristotle’s account of intellect may seem to hold some prospect of such a view. Medieval Arabic and Latin authors are influenced more by Aristotle. Throughout the early modern period, theories of substance harken back to one or more marks of substance mentioned in Aristotle’s Categories. Human minds have cognitive access to the region of ideas at all only in virtue of ideas and basic truths that are innate in them.
