Psychological Ideas

Kant says that psychological ideas attempt to identify some kind of substance or an ultimate subject that underlies all the predicates we can apply to a subject. He says that this is pointless because the understanding helps us make sense of experience by applying pure concepts to empirical intuitions and concepts take the form of predicates. So knowledge comes in the form of predicates attached to subjects. Kant says that we can consider the ego or soul as an ultimate subject because we refer to an "I" when we describe any internal state, but he says that we cannot have knowledge of this "I" in itself. The fact that we are capable of experience suggests that we have consciousness, but we refer to it without having any ample knowledge of it, we can know nothing about our consciousness, we can only know about appearances. All that we can say about our consciousness or "soul" is in reference to our own experience.