But if in human beings consciousness appears, what are its marks, and how is it known? Ought we not to define it at starting? I believe it cannot be defined. Definition is taking an idea to pieces. But there are no pieces in the idea of consciousness. It is elementary, something in which all other pieces begin. That is, in attempting to define consciousness, I must in every definition employed really assume that my hearer is acquainted with it already. I cannot then define it without covert reference to experience. I might vary the term and call it awaredness, internal observation, psychic response. I might say it is that which accompanies all experience and makes it to be experience. But these are not definitions. A simple way to fix attention on it is to say that it is what we feel less and less as we sink into a swoon. What this is, I cannot more precisely state. But in swoon or sleep we are all familiar with its diminution or increase, and we recognize in it the very color of our being. After my friend's remark I am in a different state from that in which I was before. Something has affected me which may abide. This is not the case with a stone post, or at least there are no signs of it there. The post, then, is unconscious. We call ourselves conscious. In unconsciousness our lives began, and from it they have not altogether emerged. Yet unconsciousness is a matter of degree. We may be very much aware, aware but slightly, vanishingly, not at all. Even though we never existed unconsciously, we may fairly assume such a blank terminus in order the better to figure the present condition of our minds. They show sinking degrees moving off in that direction; when we think out the series, we come logically to a point where there is no consciousness at all. Such a point analogy also inclines us to concede. In our body we come upon unconscious sections. This body seems to have some connection with myself; yet of its large results only, and not of its minuter operations, can I be distinctly aware. In like manner it is held that within the mind processes cumulate and rise to a certain height before they cross the threshold of consciousness. Below that threshold, though actual processes, they are unknown to us. The teaching of modern psychology is that all mental action is at the start unconscious, requiring a certain bulk of stimulus in order to emerge into conditions where we become aware of it. The cumulated result we know; the minute factors which must be gathered together to form that result, we do not know. I do not pronounce judgment on this psychological question. I state the belief merely in order to show how probable it is that our conscious life is superposed upon unconscious conditions.