To show how the content of history comes to be distinguished from that of art in the narrow sense, we must recall what has already been observed as to the ideal character of the intuition or first perception, in which all is real and therefore nothing is real. Only at a later stage does the spirit form the concepts of external and internal, of what has happened and what is desired, of object and subject, and the like: only at this later stage, that is, does it distinguish historical from non-historical intuition, the _real_ from the _unreal,_ real imagination from pure imagination. Even internal facts, what is desired and imagined, castles in the air, and countries of Cockaigne, have their reality, and the soul, too, has its history. His illusions form part of the biography of every individual as real facts. But the history of an individual soul is history, because the distinction between the real and the unreal is always active in it, even when the illusions themselves are the real. But these distinctive concepts do not appear in history like the concepts of science, but rather like those that we have seen dissolved and melted in the æsthetic intuitions, although in history they stand out in a manner altogether special to themselves. History does not construct the concepts of the real and unreal, but makes use of them. History, in fact, is not the theory of history. Mere conceptual analysis is of no use in ascertaining whether an event in our lives was real or imaginary. We must mentally reproduce the intuitions in the most complete form, as they were at the moment of production. Historicity is distinguished in the concrete from pure imagination as any one intuition is distinguished from any other: in memory. [Sidenote: _Historical criticism._] Where this is not possible, where the delicate and fleeting shades between the real and unreal intuitions are so slight as to mingle the one with the other, we must either renounce for the time being at least the knowledge of what really happened (and this we often do), or we must fall back upon conjecture, verisimilitude, probability. The principle of verisimilitude and of probability in fact dominates all historical criticism. Examination of sources and authorities is devoted to establishing the most credible evidence. And what is the most credible evidence, save that of the best observers, that is, of those who best remember and (be it understood) have not wished to falsify, nor had interest in falsifying the truth of things? [Sidenote: _Historical scepticism._]