Page:Popular Science Monthly Volume 68.djvu/224

 220 of the thought, I have the further consciousness that I have already had this thought, that it is familiar to me.

Similar, though somewhat more complicated, is the phenomenon in the case of experiences in which the external world had participated. After eating an apple, I may repeat this experience in two ways. I may repeat it as an inner experience, though with diminished intensity. Another part, the sensations that formed a piece of my experience, I am unable at will to reproduce in myself; but am compelled again to eat an apple in order to have a similar experience in this respect as well. This is a complete repetition that it is not necessarily in my power to produce because it is essential that I have an apple, i. e., that certain conditions belonging to the external world and independent of myself be fulfilled.

Whether in the repetition of an experience the outer world takes part or not has no influence upon the content of consciousness, called 'memory.' It follows, therefore, that the latter belongs wholly to internal experience, and that we remember an external event only through its inner constituents. The mere repetition of corresponding sense impressions is not sufficient. We may see the same individual repeatedly without recognizing him in case the accompanying inner phenomena have, through lack of interest, been so slight that their repetition does not produce this content of consciousness, 'memory.' If, however, we see him very often, the frequent repetition of the external impression finally produces the memory of the inner experience that goes with it.

Hence it follows that to call forth the reaction, 'memory,' a definite intensity of the internal experience is necessary. This threshold value may be attained either at one time by one strong impression, or by numerous repetitions of weak ones. The repetitions are the more effective, the more rapidly they follow upon one another. Hence we may conclude further that the memory value of an experience, or its power upon repetition to call forth the reaction, 'memory,' diminishes in the course of time.

Furthermore we must take into consideration the above-mentioned fact that a completely accurate reproduction of an experience never takes place. The reaction, 'memory,' must therefore be called forth when in place of complete correspondence there is merely similarity or partial correspondence. Here, too, there are gradations. Memory appears the more easily, the more completely the two experiences correspond; and vice versa.

If we look at these relations from a physiological point of view, we are able to say: We possess two kinds of contrivances or organs, of which one is independent of, and the other dependent upon, our will. The former are the organs of sense, the latter is the organ of thought.