REACTION AND CONSCIOUSNESS
One of the striking things about consciousness is that it may vary in degree: I may be more or less conscious of any given content, without any change in the content itself. As I sit here at the present moment, I am conscious of the whirring of the electric fan in the next room. This whir is a constant sound, which affects my auditory receptors continuously. Its intensity, pitch and timber do not change to an appreciable extent. Yet, at one moment, I am "vividly" conscious of it: or I might say, it is a "vivid" sound. At another moment, I am conscious of it much less vividly: it becomes a part of the "background" of content. Yet the stimulation of my auditory receptors is the same at both moments.
Another way of expressing these facts is to say that I am more attentive to the noise at one moment than at another. Attention and consciousness, in fact, are terms which are to a large extent synonymous: attention is, however, used most generally to designate the higher degrees of consciousness. When I am "attentive" to any content, I am highly (in degree) conscious of that content. When I say that I am "inattentive," I mean that the degree of consciousness is low. We speak of attentive consciousness as vivid consciousness; and we say also that the content is vivid, meaning that we are vividly conscious of it.
Although we cannot say strictly that consciousness is complex, or composite (although its conditions are highly complex), yet we do find that at a given moment we are vividly conscious of one detail of content, and less vividly conscious of other details. I may be conscious of the noise of the fan, and of some one's voice, at the same time; vividly conscious of one, and much less vividly conscious of the other. I may be conscious of auditory, visual and olfactory objects at the same time that I am conscious