§ 7. The data or material of reality, then, are facts of experience, and nothing but facts of experience.[19] And experience, we have said, means for our purposes _immediate_ feeling or apprehension. What _immediacy_ means, as we have already seen, we cannot further explain in psychological terms, except by saying that it is what distinguishes an actual mental state from the mere thought of that state. The reason why, in Psychology, we have to be content with such an account is manifest. To characterise immediate feeling further, we should have to identify the _qualities_ by which it is universally marked off from what is not immediate. We should, in fact, have to describe it in general terms, and before we can do this we must cease to feel or apprehend directly, and go on to reflect upon and analyse the contents of our apprehension. What our psychological description depicts is never the experience as it actually was while we were having it, but the experience as it appears from the point of view of subsequent reflection, interpreted in the light of all sorts of conscious or unconscious hypotheses about its conditions and its constituents. Thus our psychological descriptions depend for their very possibility upon the recognition of distinctions which are not present, as such, in the experience itself as directly presented to us but created by later reflection about it From the point of view of Metaphysics, however, it is possible to specify one universal characteristic of immediate feeling, which is of the utmost importance for our theories of reality and of knowledge. When we reflect upon any psychical fact whatever, we may distinguish within it two very different aspects. There is, in the first place, the fact that it _does_ happen, that it is a genuine psychical occurrence,—the existence or _that_, as we may call it, of the piece of psychical fact in question; and there is also the peculiar character or quality which gives _this_ mental occurrence its unique nature as distinguished from any other which might conceivably have been presented in its stead,—the content or _what_ of the psychical fact. Thus a simple colour-sensation, say that of green, has its _that_,—it is actually present, and is thus distinguished from a merely remembered or anticipated sensation; it has also its _what_,—the peculiar quality by which it is distinguished, for example, from a sensation of blue. So again with an imagined sensation; it is actually imagined, the imagining of it is an actual occurrence with its particular place in the course of the occurrences which together make up my mental life; and again, it is the imagination of some content with qualities of its own by which it is distinguished from any other content.