It is contended by some writers that the mind is never at rest, and that even during the most profound sleep dreams take place, which are either forgotten immediately, or which make no impression on the memory. That this view is erroneous is, I think, very evident. If it were correct, the first object of sleep--rest for the brain--would not be attained. We all know how fatigued we are, and how indisposed to exertion the brain is, after a night of continued dreaming, and we can easily imagine what would be the consequences if such a condition were kept up night after night. To say that we really do dream not only every night, but every instant of the night, in fact always and continually when we sleep, but that we forget our dreams as soon as they are formed, remembering solely those which are most vivid, is making assertions which not only are without proof, but which are impossible of proof. For if, as Locke[65] remarks, the sleeping man on awaking has no recollection of his thoughts, it is very certain that no one else can recollect them for him. The observations of Locke on this point are extremely appropriate, and, to my mind, very philosophical and logical. After insisting that, sleeping or waking, a man cannot think without being sensible of it, he says:[66] “I grant that the soul of a waking man is never without thought, because it is the condition of being awake; but whether sleeping without dreaming be not an affection of the whole man, mind as well as body, may be worth a waking man’s consideration, it being hard to conceive that anything should think and not be conscious of it. If the soul doth think in a sleeping man without being conscious of it, I ask, whether during such thinking it has any pleasure or pain, or be capable of happiness or misery? I am sure the man is not, any more than the bed or earth he lies on, for to be happy or miserable without being conscious of it seems to me utterly inconsistent and impossible. Or if it be possible that the soul can, while the body is sleeping, have its thinkings, enjoyments, and concerns, its pleasure or pain, about which the man is not conscious of nor partakes in, it is certain that Socrates asleep and Socrates awake is not the same person; but his soul when he sleeps and Socrates the man, consisting of body and soul when he is waking, are two persons, since waking Socrates has no knowledge of or concernment for that happiness or misery of his soul which it enjoys alone by itself while he sleeps without perceiving anything of it, any more than he has for the happiness or misery of a man in the Indies whom he knows not; for if we take wholly away all consciousness of our actions and sensations, especially of pleasure and pain, and the concernment that accompanies it, it will be hard to know wherein to place personal identity.”