On Sleep and Dreams
The nature of sleep as a suspension of sentient consciousness; the nature of dreams as partial activity of the senses during sleep.
Sleep is a more or less perfect suspension of the activities of sentient life — what Aristotle called a binding up of the common sense. Since, in man's earthly life, intellect is extrinsically dependent upon sentiency, the binding up of sentient consciousness involves the suspension of normal rational consciousness. Sleep is necessary for the restoration of the central sense (consciousness) and for the recuperation of the sense-organs, nerves, and muscles. During sleep, the senses other than sense-consciousness are sometimes active: the internal senses of imagination and sentient memory, and occasionally the outer senses, can operate — and this activity constitutes dreaming. Dreams are thus images reproduced by the imagination during sleep, recognized by sense-memory as familiar, and sometimes reaching sense-consciousness in a fragmentary way.
Sleep is a more or less perfect suspension of the activities of sentient life. Aristotle called it a binding up of the common sense (that is, of sentient consciousness). Since, in man’s earthly life, intellect is extrinsically dependent upon sentiency, the binding up of sentient consciousness involves the suspension of normal rational consciousness. Further: the sentient consciousness is that “awareness” which renders serviceable all activities of the interior and exterior senses, and these activities are a constant drain upon its resources. Therefore it is to be expected that a period, more or less protracted, should sometimes be allotted by nature to the restoration of force and vigor in this much-worked faculty. In addition to the fatigue which affects the central or common sense (consciousness) there is that of the sense-organs, nerves, and muscles, which is experienced in the sentient portion of the central axis. Now, the brain is the organ of the central sense and the focus, so to speak, of nervous and muscular activity. It is quite natural therefore that the brain should relax for rest and recuperation; and that this occurs in sleep is manifested by the fact that the head grows heavy and tends to fall forward when a person is sleepy.
Sometimes the senses other than sense-consciousness are active when a person sleeps, as the internal sense of imagination, and that of memory, are when we dream, and as outer senses are when we talk or walk or toss about in our sleep. Here again we have evidence that it is, first and foremost, the sense-consciousness or common sense which is affected by sleep.
The explanation of the common experience of sleep, then, is this: the central sense, exhausted by its constant service of unifying and supervising the activities of the other senses, undergoes a periodic suspension of its activity. This suspension is sleep. During sleep, the other senses — particularly the inner senses of imagination and sentient memory — may remain partially active, presenting images which arise from the organism’s own internal states and from the residua of past sense-experience. This partial, unsupervised activity of the inner senses during the suspension of consciousness constitutes dreaming.
Dreams are, therefore, images reproduced by the imagination during the suspension of full sense-consciousness; these images are sometimes recognized by sense-memory as familiar, as records of the actual past; and occasionally they reach even the partially active sense-consciousness in a fragmentary and uncoordinated way. The content of dreams is thus always derived from past sense-experience, however wildly rearranged or distorted by the imagination’s rearranging activity unguided by the waking rational control.
The philosophical significance of dreams is chiefly negative: they demonstrate that the inner senses (imagination and sense-memory) are distinct from sense-consciousness (the common sense), since they can operate while consciousness is suspended. They also illustrate the essential difference between the inner senses and the intellect: intellectual knowledge persists through sleep unimpaired (the geometer’s knowledge of geometry does not dissolve during sleep), while the inner senses are precisely those which are affected.