I might as well doubt of my own being, as of the being of those things I actually see and feel.
George BerkeleyThis perceiving, active being is what I call mind, spirit, soul, or myself. 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, whereby they are perceived; for the existence of an idea consists in being perceived.
George Berkeley