This brings us in another fashion to the subject of the last chapter, and to another reason for the great memories of genius. The more significant a man is, the more different personalities he unites in himself, the more interests that are contained in him, the more wide his memory must be. All men have practically the same opportunities of perception, but the vast majority of men apprehend only an infinitesimal part of what they have perceived. The ideal genius is one in whom perception and apprehension are identical in their field. Of course no such being actually exists. On the other hand, there is no man who has apprehended nothing that he has perceived. In this way we may take it that all degrees of genius (not talent) exist; no male is quite without a trace of genius. Complete genius is an ideal; no man is absolutely without the quality, and no man possesses it completely. Apprehension or absorption, and memory or retention, vary together in their extent and their permanence. There is an uninterrupted gradation from the man whose mentality is unconnected from moment to moment, and to whom no incidents can signify anything because there is within him nothing to compare them with (such an extreme, of course, does not exist) to the fully developed minds for which everything is unforgettable, because of the firm impressions made and the sureness with which they are absorbed. The extreme of genius also does not exist, because even the greatest genius is not wholly a genius at every moment of his life. What is at once a deduction from the necessary connection between memory and genius, and a proof of the actuality of the connection, lies in the extraordinary memory for minute details shown by the man of genius. Because of the universality of his mind, everything has only one interpretation for him, an interpretation often unsuspected at the time; and so things cling obstinately in his memory and remain there inextinguishably, although he may have taken not the smallest trouble to take note of them. And so one may almost take as another mark of the genius that the phrase “this is no longer true” has no meaning for him. There is nothing that is no longer true for him, probably just because he has a clearer idea than other men of the changes that come with time.