Principles Of Human Knowledge - pg. 103

But besides all that endless variety of ideas or objects of knowledge, there is likewise something which knows or perceives them, and exercises divers operations, as willing, imagining, rmemebering about them. This perceiving, active being is what I call mind, spirit, soul or my self. By which words I do not denote any one of my ideas, but a thing entirely distinct from them, wherein they exist, or, which is the same thing, where they are perceieved; for the existence of an idea consists in being perceived.