Page:Popular Science Monthly Volume 48.djvu/209

Rh involves a very complex co-ordination of the forces that underlie it. And I have also shown that the permanent existence of any element of consciousness, if at all complex, involves not merely a co-ordination, which might be temporary, but a permanent organization of certain of those forces into enduring systems. Not enduring in the sense that they are always actively operating, but in the sense that when any one element is active it calls into activity the other elements as well. The same is true of consciousness as a whole. We may discern this in two quite different forms. The first is what we may call the permanent form of consciousness. We observe that at any given time consciousness has a certain form of organization which is so constant that we are tempted to think it can not exist in any other form. Some one element or organized group of elements tends to be more clear and distinct than the others. This one is called the center of attention or focus of consciousness; the others constitute the margin. From moment to moment the focus shifts; new elements rise into dominance, and the old fade away. Yet there is always a dominant element, and this it is to which we attend. Usually the focus and margin are inversely related to one another; that is to say, when any given group tends to become more clear and distinct the other elements tend to lose with respect to clearness and distinctness. This is what we mean when we say that we can not attend to two things at once. But it is not always true. There are states in which the heightening of one element tends to heighten all the others as well. In imminent danger, for instance, there is frequently an intense exaltation of the total content of consciousness, and the same phenomenon is occasionally found as a precursor of an epileptic attack. Now, this constant form into which consciousness tends to fall, and which is, by the way, the basis of our notion that the mind is a single entity of some sort, is very suggestive. We know that all physical forces, if they can in any way act upon one another, tend to coalesce into one common resultant, and I think it probable that in the law of attention we see the mental manifestation of some form of coalescence between the physical forces which form its basis.

Again, the consciousness of each of us forms a permanent entity which we severally call "myself." Into all the problems connected with this word of many meanings I can not enter, but of one thing we may be quite certain—whatever the consciousness of self may be, it is largely dependent upon the continuity and uniformity of our memories. Any great change in a man's life which introduces into his present a mass of experiences quite out of keeping with his past is apt to introduce into his consciousness of personal identity a strange sense of unreality and uncertainty. He rubs his eyes and says: "Who am I? Am I really John