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 whilst he sleeps, without perceiving anything of it; no 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.

12.  If a sleeping Man thinks without knowing it, the sleeping and waking Man are two Persons.

The soul, during sound sleep, thinks, say these men.  Whilst it thinks and perceives, it is capable certainly of those of delight or trouble, as well as any other perceptions; and it must necessarily be conscious of its own perceptions.  But it has all this apart:  the sleeping man, it is plain, is conscious of nothing of all this.  Let us suppose, then, the soul of Castor, while he is sleeping, retired from his body; which is no impossible supposition for the men I have here to do with, who so liberally allow life, without a thinking soul, to all other animals.  These men cannot then judge it impossible, or a contradiction, that the body should live without the soul; nor that the soul should subsist and think, or have perception, even perception of happiness or misery, without the body.  Let us then, I say, suppose the soul of Castor separated during his sleep from his body, to think apart.  Let us suppose, too, that it chooses for its scene of thinking the body of another man, v. g.  Pollux, who is sleeping without a soul.  For, if Castor’s soul can think, whilst Castor is asleep, what Castor is never conscious of, it is no matter what place it chooses to think in.  We have here, then, the bodies of two men with only one soul between them, which we will suppose to sleep and wake by turns; and the soul still thinking in the waking man, whereof the sleeping man is never conscious, has never the least perception.  I ask, then, whether Castor and Pollux, thus with only one soul between them, which thinks and perceives in one what the other is never conscious of, nor is concerned for, are not two as distinct persons as Castor and Hercules, or as Socrates and Plato were?  And whether one of them might not be very happy, and the other very miserable?  Just by the same reason, they make the soul and the man two persons, who make the soul think apart what the man is not conscious of.  For, I suppose nobody will make identity of persons to consist in the soul’s being united to the very same numerical particles of matter.  For if that be necessary to identity, it will be impossible, in that constant flux of the particles of our bodies, that any man should be the same person two days, or two moments, together.