may suppose, though they have acquaintance with sense-data, never become aware of this acquaintance, and thus never know of their own existence. I do not mean that they doubt whether they exist, but that they have never become conscious of the fact that they have sensations and feelings, nor therefore of the fact that they, the subjects of their sensations and feelings, exist.
We have spoken of acquaintance with the contents of our minds as self-consciousness, but it is not, of course, consciousness of our self: it is consciousness of particular thoughts and feelings. The question whether we are also acquainted with our bare selves, as opposed to particular thoughts and feelings, is a very difficult one, upon which it would be rash to speak positively. When we try to look into ourselves we always seem to come upon some particular thought or feeling, and not upon the "I" which has the thought or feeling. Nevertheless there are some reasons for thinking that we are acquainted with the "I," though the acquaintance is hard to disentangle from other things. To make clear
