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 al 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, etc., 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 s