1. Wherein identity consists. Another occasion the mind often
takes of comparing, is the very being of things, when, considering
anything as existing at any determined time and place, we compare it
with itself existing at another time, and thereon form the ideas of
identity and diversity. When we see anything to be in any place in any
instant of time, we are sure (be it what it will) that it is that very
thing, and not another which at that same time exists in another
place, how like and undistinguishable soever it may be in all other
respects: and in this consists identity, when the ideas it is
attributed to vary not at all from what they were that moment
wherein we consider their former existence, and to which we compare
the present. For we never finding, nor conceiving it possible, that
two things of the same kind should exist in the same place at the same
time, we rightly conclude, that, whatever exists anywhere at any time,
excludes all of the same kind, and is there itself alone. When
therefore we demand whether anything be the same or no, it refers
always to something that existed such a time in such a place, which it
was certain, at that instant, was the same with itself, and no
other. From whence it follows, that one thing cannot have two
beginnings of existence, nor two things one beginning; it being
impossible for two things of the same kind to be or exist in the
same instant, in the very same place; or one and the same thing in
different places. That, therefore, that had one beginning, is the same
thing; and that which had a different beginning in time and place from
that, is not the same, but diverse. That which has made the difficulty
about this relation has been the little care and attention used in
having precise notions of the things to which it is attributed.
  2. Identity of substances. We have the ideas but of three sorts of
substances: 1. God. 2. Finite intelligences. 3. Bodies.
  First, God is without beginning, eternal, unalterable, and
everywhere, and therefore concerning his identity there can be no
doubt.
  Secondly, Finite spirits having had each its determinate time and
place of beginning to exist, the relation to that time and place
will always determine to each of them its identity, as long as it
exists.
  Thirdly, The same will hold of every particle of matter, to which no
addition or subtraction of matter being made, it is the same. For,
though these three sorts of substances, as we term them, do not
exclude one another out of the same place, yet we cannot conceive
but that they must necessarily each of them exclude any of the same
kind out of the same place: or else the notions and names of
identity and diversity would be in vain, and there could be no such
distinctions of substances, or anything else one from another. For
example: could two bodies be in the same place at the same time;
then those two parcels of matter must be one and the same, take them
great or little; nay, all bodies must be one and the same. For, by the
same reason that two particles of matter may be in one place, all
bodies may be in one place: which, when it can be supposed, takes away
the distinction of identity and diversity of one and more, and renders
it ridiculous. But it being a contradiction that two or more should be
one, identity and diversity are relations and ways of comparing well
founded, and of use to the understanding.
  Identity of modes and relations. All other things being but modes or
relations ultimately terminated in substances, the identity and
diversity of each particular existence of them too will be by the same
way determined: only as to things whose existence is in succession,
such as are the actions of finite beings, v.g. motion and thought,
both which consist in a continued train of succession, concerning
their diversity there can be no question: because each perishing the
moment it begins, they cannot exist in different times, or in
different places, as permanent beings can at different times exist
in distant places; and therefore no motion or thought, considered as
at different times, can be the same, each part thereof having a
different beginning of existence.
  3. Principium Individuationis. From what has been said, it is easy
to discover what is so much inquired after, the principium
individuationis; and that, it is plain, is existence itself; which
determines a being of any sort to a particular time and place,
incommunicable to two beings of the same kind. This, though it seems
easier to conceive in simple substances or modes; yet, when
reflected on, is not more difficult in compound ones, if care be taken
to what it is applied: v.g. let us suppose an atom, i.e. a continued
body under one immutable superficies, existing in a determined time
and place; it is evident, that, considered in any instant of its
existence, it is in that instant the same with itself. For, being at
that instant what it is, and nothing else, it is the same, and so must
continue as long as its existence is continued; for so long it will be
the same, and no other. In like manner, if two or more atoms be joined
together into the same mass, every one of those atoms will be the
same, by the foregoing rule: and whilst they exist united together,
the mass, consisting of the same atoms, must be the same mass, or
the same body, let the parts be ever so differently jumbled. But if
one of these atoms be taken away, or one new one added, it is no
longer the same mass or the same body. In the state of living
creatures, their identity depends not on a mass of the same particles,
but on something else. For in them the variation of great parcels of
matter alters not the identity: an oak growing from a plant to a great
tree, and then lopped, is still the same oak; and a colt grown up to a
horse, sometimes fat, sometimes lean, is all the while the same horse:
though, in both these cases, there may be a manifest change of the
parts; so that truly they are not either of them the same masses of
matter, though they be truly one of them the same oak, and the other
the same horse. The reason whereof is, that, in these two cases- a
mass of matter and a living body- identity is not applied to the
same thing.
  4. Identity of vegetables. We must therefore consider wherein an oak
differs from a mass of matter, and that seems to me to be in this,
that the one is only the cohesion of particles of matter any how
united, the other such a disposition of them as constitutes the
parts of an oak; and such an organization of those parts as is fit
to receive and distribute nourishment, so as to continue and frame the
wood, bark, and leaves, &c., of an oak, in which consists the
vegetable life. That being then one plant which has such an
organization of parts in one coherent body, partaking of one common
life, it continues to be the same plant as long as it partakes of
the same life, though that life be communicated to new particles of
matter vitally united to the living plant, in a like continued
organization conformable to that sort of plants. For this
organization, being at any one instant in any one collection of
matter, is in that particular concrete distinguished from all other,
and is that individual life, which existing constantly from that
moment both forwards and backwards, in the same continuity of
insensibly succeeding parts united to the living body of the plant, it
has that identity which makes the same plant, and all the parts of it,
parts of the same plant, during all the time that they exist united in
that continued organization, which is fit to convey that common life
to all the parts so united.
  5. Identity of animals. The case is not so much different in
brutes but that any one may hence see what makes an animal and
continues it the same. Something we have like this in machines, and
may serve to illustrate it. For example, what is a watch? It is
plain it is nothing but a fit organization or construction of parts to
a certain end, which, when a sufficient force is added to it, it is
capable to attain. If we would suppose this machine one continued
body, all whose organized parts were repaired, increased, or
diminished by a constant addition or separation of insensible parts,
with one common life, we should have something very much like the body
of an animal; with this difference, That, in an animal the fitness
of the organization, and the motion wherein life consists, begin
together, the motion coming from within; but in machines the force
coming sensibly from without, is often away when the organ is in
order, and well fitted to receive it.
  6. The identity of man. This also shows wherein the identity of
the same man consists; viz. in nothing but a participation of the same
continued life, by constantly fleeting particles of matter, in
succession vitally united to the same organized body. He that shall
place the identity of man in anything else, but, like that of other
animals, in one fitly organized body, taken in any one instant, and
from thence continued, under one organization of life, in several
successively fleeting particles of matter united to it, will find it
hard to make an embryo, one of years, mad and sober, the same man,
by any supposition, that will not make it possible for Seth, Ismael,
Socrates, Pilate, St. Austin, and Caesar Borgia, to be the same man.
For if the identity of soul alone makes the same man; and there be
nothing in the nature of matter why the same individual spirit may not
be united to different bodies, it will be possible that those men,
living in distant ages, and of different tempers, may have been the
same man: which way of speaking must be from a very strange use of the
word man, applied to an idea out of which body and shape are excluded.
And that way of speaking would agree yet worse with the notions of
those philosophers who allow of transmigration, and are of opinion
that the souls of men may, for their miscarriages, be detruded into
the bodies of beasts, as fit habitations, with organs suited to the
satisfaction of their brutal inclinations. But yet I think nobody,
could he be sure that the soul of Heliogabalus were in one of his
hogs, would yet say that hog were a man or Heliogabalus.
  7. Idea of identity suited to the idea it is applied to. It is not
therefore unity of substance that comprehends all sorts of identity,
or will determine it in every case; but to conceive and judge of it
aright, we must consider what idea the word it is applied to stands
for: it being one thing to be the same substance, another the same
man, and a third the same person, if person, man, and substance, are
three names standing for three different ideas;- for such as is the
idea belonging to that name, such must be the identity; which, if it
had been a little more carefully attended to, would possibly have
prevented a great deal of that confusion which often occurs about this
matter, with no small seeming difficulties, especially concerning
personal identity, which therefore we shall in the next place a little
consider.
  8. Same man. An animal is a living organized body; and
consequently the same animal, as we have observed, is the same
continued life communicated to different particles of matter, as
they happen successively to be united to that organized living body.
And whatever is talked of other definitions, ingenious observation
puts it past doubt, that the idea in our minds, of which the sound man
in our mouths is the sign, is nothing else but of an animal of such
a certain form. Since I think I may be confident, that, whoever should
see a creature of his own shape or make, though it had no more
reason all its life than a cat or a parrot, would call him still a
man; or whoever should hear a cat or a parrot discourse, reason, and
philosophize, would call or think it nothing but a cat or a parrot;
and say, the one was a dull irrational man, and the other a very
intelligent rational parrot. A relation we have in an author of
great note, is sufficient to countenance the supposition of a rational
parrot.
  His words are: "I had a mind to know, from Prince Maurice's own
mouth, the account of a common, but much credited story, that I had
heard so often from many others, of an old parrot he had in Brazil,
during his government there, that spoke, and asked, and answered
common questions, like a reasonable creature: so that those of his
train there generally concluded it to be witchery or possession; and
one of his chaplains, who lived long afterwards in Holland, would
never from that time endure a parrot, but said they all had a devil in
them. I had heard many particulars of this story, and as severed by
people hard to be discredited, which made me ask Prince Maurice what
there was of it. He said, with his usual plainness and dryness in
talk, there was something true, but a great deal false of what had
been reported. I desired to know of him what there was of the first.
He told me short and coldly, that he had heard of such an old parrot
when he had been at Brazil; and though he believed nothing of it,
and it was a good way off, yet he had so much curiosity as to send for
it: that it was a very great and a very old one; and when it came
first into the room where the prince was, with a great many Dutchmen
about him, it said presently, What a company of white men are here!
They asked it, what it thought that man was, pointing to the prince.
It answered, Some General or other. When they brought it close to him,
he asked it, D'ou venez-vous? It answered, De Marinnan. The Prince,
A qui estes-vous? The Parrot, A un Portugais. The Prince, Que
fais-tu la? Parrot, Je garde les poulles. The Prince laughed, and
said, Vous gardez les poulles? The Parrot answered, Oui, moi; et je
scai bien faire; and made the chuck four or five times that people use
to make to chickens when they call them. I set down the words of
this worthy dialogue in French, just as Prince Maurice said them to
me. I asked him in what language the parrot spoke, and he said in
Brazilian. I asked whether he understood Brazilian; he said No, but he
had taken care to have two interpreters by him, the one a Dutchman
that spoke Brazilian, and the other a Brazilian that spoke Dutch; that
he asked them separately and privately, and both of them agreed in
telling him just the same thing that the parrot had said. I could
not but tell this odd story, because it is so much out of the way, and
from the first hand, and what may pass for a good one; for I dare
say this Prince at least believed himself in all he told me, having
ever passed for a very honest and pious man: I leave it to naturalists
to reason, and to other men to believe, as they please upon it;
however, it is not, perhaps, amiss to relieve or enliven a busy
scene sometimes with such digressions, whether to the purpose or no."
  I have taken care that the reader should have the story at large
in the author's own words, because he seems to me not to have
thought it incredible; for it cannot be imagined that so able a man as
he, who had sufficiency enough to warrant all the testimonies he gives
of himself, should take so much pains, in a place where it had nothing
to do, to pin so close, not only on a man whom he mentions as his
friend, but on a Prince in whom he acknowledges very great honesty and
piety, a story which, if he himself thought incredible, he could not
but also think ridiculous. The Prince, it is plain, who vouches this
story, and our author, who relates it from him, both of them call this
talker a parrot: and I ask any one else who thinks such a story fit to
be told, whether, if this parrot, and all of its kind, had always
talked, as we have a prince's word for it this one did,- whether, I
say, they would not have passed for a race of rational animals; but
yet, whether, for all that, they would have been allowed to be men,
and not parrots? For I presume it is not the idea of a thinking or
rational being alone that makes the idea of a man in most people's
sense: but of a body, so and so shaped, joined to it: and if that be
the idea of a man, the same successive body not shifted all at once,
must, as well as the same immaterial spirit, go to the making of the
same man.
  9. Personal identity. This being premised, to find wherein
personal identity consists, we must consider what person stands
for;- which, I think, is a thinking intelligent being, that has reason
and reflection, and can consider itself as itself, the same thinking
thing, in different times and places; which it does only by that
consciousness which is inseparable from thinking, and, as it seems
to me, essential to it: it being impossible for any one to perceive
without perceiving that he does perceive. When we see, hear, smell,
taste, feel, meditate, or will anything, we know that we do so. Thus
it is always as to our present sensations and perceptions: and by this
every one is to himself that which he calls self:- it not being
considered, in this case, whether the same self be continued in the
same or divers substances. For, since consciousness always accompanies
thinking, and it is that which makes every one to be what he calls
self, and thereby distinguishes himself from all other thinking
things, in this alone consists personal identity, i.e. the sameness of
a rational being: and as far as this consciousness can be extended
backwards to any past action or thought, so far reaches the identity
of that person; it is the same self now it was then; and it is by
the same self with this present one that now reflects on it, that that
action was done.
  10. Consciousness makes personal identity. But it is further
inquired, whether it be the same identical substance. This few would
think they had reason to doubt of, if these perceptions, with their
consciousness, always remained present in the mind, whereby the same
thinking thing would be always consciously present, and, as would be
thought, evidently the same to itself. But that which seems to make
the difficulty is this, that this consciousness being interrupted
always by forgetfulness, there being no moment of our lives wherein we
have the whole train of all our past actions before our eyes in one
view, but even the best memories losing the sight of one part whilst
they are viewing another; and we sometimes, and that the greatest part
of our lives, not reflecting on our past selves, being intent on our
present thoughts, and in sound sleep having no thoughts at all, or
at least none with that consciousness which remarks our waking
thoughts,- I say, in all these cases, our consciousness being
interrupted, and we losing the sight of our past selves, doubts are
raised whether we are the same thinking thing, i.e. the same substance
or no. Which, however reasonable or unreasonable, concerns not
personal identity at all. The question being what makes the same
person; and not whether it be the same identical substance, which
always thinks in the same person, which, in this case, matters not
at all: different substances, by the same consciousness (where they do
partake in it) being united into one person, as well as different
bodies by the same life are united into one animal, whose identity
is preserved in that change of substances by the unity of one
continued life. For, it being the same consciousness that makes a
man be himself to himself, personal identity depends on that only,
whether it be annexed solely to one individual substance, or can be
continued in a succession of several substances. For as far as any
intelligent being can repeat the idea of any past action with the same
consciousness it had of it at first, and with the same consciousness
it has of any present action; so far it is the same personal self
For it is by the consciousness it has of its present thoughts and
actions, that it is self to itself now, and so will be the same
self, as far as the same consciousness can extend to actions past or
to come. and would be by distance of time, or change of substance,
no more two persons, than a man be two men by wearing other clothes
to-day than he did yesterday, with a long or a short sleep between:
the same consciousness uniting those distant actions into the same
person, whatever substances contributed to their production.
  11. Personal identity in change of substance. That this is so, we
have some kind of evidence in our very bodies, all whose particles,
whilst vitally united to this same thinking conscious self, so that we
feel when they are touched, and are affected by, and conscious of good
or harm that happens to them, as a part of ourselves; i.e. of our
thinking conscious self. Thus, the limbs of his body are to every
one a part of Himself; he sympathizes and is concerned for them. Cut
off a hand, and thereby separate it from that consciousness he had
of its heat, cold, and other affections, and it is then no longer a
part of that which is himself, any more than the remotest part of
matter. Thus, we see the substance whereof personal self consisted
at one time may be varied at another, without the change of personal
identity; there being no question about the same person, though the
limbs which but now were a part of it, be cut off.
  12. Personality in change of substance. But the question is, Whether
if the same substance which thinks be changed, it can be the same
person; or, remaining the same, it can be different persons?
  And to this I answer: First, This can be no question at all to those
who place thought in a purely material animal constitution, void of an
immaterial substance. For, whether their supposition be true or no, it
is plain they conceive personal identity preserved in something else
than identity of substance; as animal identity is preserved in
identity of life, and not of substance. And therefore those who
place thinking in an immaterial substance only, before they can come
to deal with these men, must show why personal identity cannot be
preserved in the change of immaterial substances, or variety of
particular immaterial substances, as well as animal identity is
preserved in the change of material substances, or variety of
particular bodies: unless they will say, it is one immaterial spirit
that makes the same life in brutes, as it is one immaterial spirit
that makes the same person in men; which the Cartesians at least
will not admit, for fear of making brutes thinking things too.
  13. Whether in change of thinking substances there can be one
person. But next, as to the first part of the question, Whether, if
the same thinking substance (supposing immaterial substances only to
think) be changed, it can be the same person? I answer, that cannot be
resolved but by those who know what kind of substances they are that
do think; and whether the consciousness of past actions can be
transferred from one thinking substance to another. I grant were the
same consciousness the same individual action it could not: but it
being a present representation of a past action, why it may not be
possible, that that may be represented to the mind to have been
which really never was, will remain to be shown. And therefore how far
the consciousness of past actions is annexed to any individual
agent, so that another cannot possibly have it, will be hard for us to
determine, till we know what kind of action it is that cannot be
done without a reflex act of perception accompanying it, and how
performed by thinking substances, who cannot think without being
conscious of it. But that which we call the same consciousness, not
being the same individual act, why one intellectual substance may
not have represented to it, as done by itself, what it never did,
and was perhaps done by some other agent- why, I say, such a
representation may not possibly be without reality of matter of
fact, as well as several representations in dreams are, which yet
whilst dreaming we take for true- will be difficult to conclude from
the nature of things. And that it never is so, will by us, till we
have clearer views of the nature of thinking substances, be best
resolved into the goodness of God; who, as far as the happiness or
misery of any of his sensible creatures is concerned in it, will
not, by a fatal error of theirs, transfer from one to another that
consciousness which draws reward or punishment with it. How far this
may be an argument against those who would place thinking in a
system of fleeting animal spirits, I leave to be considered. But
yet, to return to the question before us, it must be allowed, that, if
the same consciousness (which, as has been shown, is quite a different
thing from the same numerical figure or motion in body) can be
transferred from one thinking substance to another, it will be
possible that two thinking substances may make but one person. For the
same consciousness being preserved, whether in the same or different
substances, the personal identity is preserved.
  14. Whether, the same immaterial substance remaining, there can be
two persons. As to the second part of the question, Whether the same
immaterial substance remaining, there may be two distinct persons;
which question seems to me to be built on this,- Whether the same
immaterial being, being conscious of the action of its past
duration, may be wholly stripped of all the consciousness of its
past existence, and lose it beyond the power of ever retrieving it
again: and so as it were beginning a new account from a new period,
have a consciousness that cannot reach beyond this new state. All
those who hold pre-existence are evidently of this mind; since they
allow the soul to have no remaining consciousness of what it did in
that pre-existent state, either wholly separate from body, or
informing any other body; and if they should not, it is plain
experience would be against them. So that personal identity,
reaching no further than consciousness reaches, a pre-existent
spirit not having continued so many ages in a state of silence, must
needs make different persons. Suppose a Christian Platonist or a
Pythagorean should, upon God's having ended all his works of
creation the seventh day, think his soul hath existed ever since;
and should imagine it has revolved in several human bodies; as I
once met with one, who was persuaded his had been the soul of Socrates
(how reasonably I will not dispute; this I know, that in the post he
filled, which was no inconsiderable one, he passed for a very rational
man, and the press has shown that he wanted not parts or learning;)-
would any one say, that he, being not conscious of any of Socrates's
actions or thoughts, could be the same person with Socrates? Let any
one reflect upon himself, and conclude that he has in himself an
immaterial spirit, which is that which thinks in him, and, in the
constant change of his body keeps him the same: and is that which he
calls himself: let him also suppose it to be the same soul that was in
Nestor or Thersites, at the siege of Troy, (for souls being, as far as
we know anything of them, in their nature indifferent to any parcel of
matter, the supposition has no apparent absurdity in it), which it may
have been, as well as it is now the soul of any other man: but he
now having no consciousness of any of the actions either of Nestor
or Thersites, does or can he conceive himself the same person with
either of them? Can he be concerned in either of their actions?
attribute them to himself, or think them his own, more than the
actions of any other men that ever existed? So that this
consciousness, not reaching to any of the actions of either of those
men, he is no more one self with either of them than if the soul or
immaterial spirit that now informs him had been created, and began
to exist, when it began to inform his present body; though it were
never so true, that the same spirit that informed Nestor's or
Thersites' body were numerically the same that now informs his. For
this would no more make him the same person with Nestor, than if
some of the particles of matter that were once a part of Nestor were
now a part of this man; the same immaterial substance, without the
same consciousness, no more making the same person, by being united to
any body, than the same particle of matter, without consciousness,
united to any body, makes the same person. But let him once find
himself conscious of any of the actions of Nestor, he then finds
himself the same person with Nestor.
  15. The body, as well as the soul, goes to the making of a man.
And thus may we be able, without any difficulty, to conceive the
same person at the resurrection, though in a body not exactly in
make or parts the same which he had here,- the same consciousness
going along with the soul that inhabits it. But yet the soul alone, in
the change of bodies, would scarce to any one but to him that makes
the soul the man, be enough to make the same man. For should the
soul of a prince, carrying with it the consciousness of the prince's
past life, enter and inform the body of a cobbler, as soon as deserted
by his own soul, every one sees he would be the same person with the
prince, accountable only for the prince's actions: but who would say
it was the same man? The body too goes to the making the man, and
would, I guess, to everybody determine the man in this case, wherein
the soul, with all its princely thoughts about it, would not make
another man: but he would be the same cobbler to every one besides
himself. I know that, in the ordinary way of speaking, the same
person, and the same man, stand for one and the same thing. And indeed
every one will always have a liberty to speak as he pleases, and to
apply what articulate sounds to what ideas he thinks fit, and change
them as often as he pleases. But yet, when we will inquire what
makes the same spirit, man, or person, we must fix the ideas of
spirit, man, or person in our minds; and having resolved with
ourselves what we mean by them, it will not be hard to determine, in
either of them, or the like, when it is the same, and when not.
  16. Consciousness alone unites actions into the same person. But
though the same immaterial substance or soul does not alone,
wherever it be, and in whatsoever state, make the same man; yet it
is plain, consciousness, as far as ever it can be extended- should
it be to ages past- unites existences and actions very remote in
time into the same person, as well as it does the existences and
actions of the immediately preceding moment: so that whatever has
the consciousness of present and past actions, is the same person to
whom they both belong. Had I the same consciousness that I saw the ark
and Noah's flood, as that I saw an overflowing of the Thames last
winter, or as that I write now, I could no more doubt that I who write
this now, that saw' the Thames overflowed last winter, and that viewed
the flood at the general deluge, was the same self,- place that self
in what substance you please- than that I who write this am the same
myself now whilst I write (whether I consist of all the same
substance, material or immaterial, or no) that I was yesterday. For as
to this point of being the same self, it matters not whether this
present self be made up of the same or other substances- I being as
much concerned, and as justly accountable for any action that was done
a thousand years since, appropriated to me now by this
self-consciousness, as I am for what I did the last moment.
  17. Self depends on consciousness, not on substance. Self is that
conscious thinking thing,- whatever substance made up of, (whether
spiritual or material, simple or compounded, it matters not)- which is
sensible or conscious of pleasure and pain, capable of happiness or
misery, and so is concerned for itself, as far as that consciousness
extends. Thus every one finds that, whilst comprehended under that
consciousness, the little finger is as much a part of himself as
what is most so. Upon separation of this little finger, should this
consciousness go along with the little finger, and leave the rest of
the body, it is evident the little finger would be the person, the
same person; and self then would have nothing to do with the rest of
the body. As in this case it is the consciousness that goes along with
the substance, when one part is separate from another, which makes the
same person, and constitutes this inseparable self: so it is in
reference to substances remote in time. That with which the
consciousness of this present thinking thing can join itself, makes
the same person, and is one self with it, and with nothing else; and
so attributes to itself, and owns all the actions of that thing, as
its own, as far as that consciousness reaches, and no further; as
every one who reflects will perceive.
  18. Persons, not substances, the objects of reward and punishment.
In this personal identity is founded all the right and justice of
reward and punishment; happiness and misery being that for which every
one is concerned for himself, and not mattering what becomes of any
substance, not joined to, or affected with that consciousness. For, as
it is evident in the instance I gave but now, if the consciousness
went along with the little finger when it was cut off, that would be
the same self which was concerned for the whole body yesterday, as
making part of itself, whose actions then it cannot but admit as its
own now. Though, if the same body should still live, and immediately
from the separation of the little finger have its own peculiar
consciousness, whereof the little finger knew nothing, it would not at
all be concerned for it, as a part of itself, or could own any of
its actions, or have any of them imputed to him.
  19. Which shows wherein personal identity consists. This may show us
wherein personal identity consists: not in the identity of
substance, but, as I have said, in the identity of consciousness,
wherein if Socrates and the present mayor of Queinborough agree,
they are the same person: if the same Socrates waking and sleeping
do not partake of the same consciousness, Socrates waking and sleeping
is not the same person. And to punish Socrates waking for what
sleeping Socrates thought, and waking Socrates was never conscious of,
would be no more of right, than to punish one twin for what his
brother-twin did, whereof he knew nothing, because their outsides were
so like, that they could not be distinguished; for such twins have
been seen.
  20. Absolute oblivion separates what is thus forgotten from the
person, but not from the man. But yet possibly it will still be
objected,- Suppose I wholly lose the memory of some parts of my
life, beyond a possibility of retrieving them, so that perhaps I shall
never be conscious of them again; yet am I not the same person that
did those actions, had those thoughts that I once was conscious of,
though I have now forgot them? To which I answer, that we must here
take notice what the word I is applied to; which, in this case, is the
man only. And the same man being presumed to be the same person, I
is easily here supposed to stand also for the same person. But if it
be possible for the same man to have distinct incommunicable
consciousness at different times, it is past doubt the same man
would at different times make different persons; which, we see, is the
sense of mankind in the solemnest declaration of their opinions, human
laws not punishing the mad man for the sober man's actions, nor the
sober man for what the mad man did,- thereby making them two
persons: which is somewhat explained by our way of speaking in English
when we say such an one is "not himself," or is "beside himself"; in
which phrases it is insinuated, as if those who now, or at least first
used them, thought that self was changed; the selfsame person was no
longer in that man.