Human Beings Have an Identical Self
Classic Philosophical Questions Part 6 - Metaphysics
John Locke, from An Essay Concerning Human Understanding
Kem Stone - 25 February 2008
The question of what is meant by the term “self” may fall under the scope of metaphysics, yet I do not believe
such a matter is anything more than linguistic.  While there is certainly a metaphysical mystery regarding the “I”
which is the subject of conscious awareness, questions concerning what we can designate as a “self” or “person”
address only the way we speak and think about the matter, rather than addressing the mystery itself.  John Locke
offers a perfectly reasonable argument to identify a person with his or her consciousness, insofar as consciousness
unites different experiences and physical substances over time.  Yet we could just as easily choose a different way
of defining a person without any change in whatever metaphysical scheme we adopt.  The only real consequences
of the definition we select will belong to ethics, as questions are raised about the justice or injustice of punishing a
person for an action that, depending on our definition of person, he may or may not be accountable.

Locke defines a person as “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” (394).  The self, or a person’s identity, consists in his or her consciousness, and as far
as it can be extended backwards in time to past thoughts or actions, we consider these to be done by the same
self.  This would seem at first to be a perfectly acceptable definition, yet there is one particular difficulty with the
idea that Locke must address: the inconsistency of memory.  Human beings do not remember every past action as
though they constantly had their whole lives before their eyes, but are conscious of only a few past events at a
time.  Most past moments are forgotten altogether.  And when a person is asleep, there is no such consciousness
of past events, so it would seem that someone is a different person while awake than while sleeping.

All of these questions raise doubts about whether we are the same thinking substance throughout our lives.  This is
a metaphysical question, yet Locke is not required to answer it as his definition of a person does not depend upon
identity with a substance, but consciousness only.  In Locke’s time, it was believed that thought must consist in
some substance, and while today we think about it differently, even then it was unknown what sort of substance
this could be.  Yet Locke’s arguments do not depend on the nature of this hypothetical substance, as a person’s
identity is bound up with consciousness alone, and would no more be a different person if transferred to a different
physical or immaterial mental substance than a man would be a different person than he was yesterday by wearing
different clothes today.  If you cut off a man’s hand and it is no longer a part of the conscious self, it no longer
belongs to the person, and thus there is a change in substance without a change in personal identity.

Locke asks, “Whether if the same substance which thinks be changed, it can be the same person; or, remaining
the same, it can be different persons?” (395).  As to the question of whether it can be the same person if the
substance is changed, Locke first points out that those who deny the existence of an immaterial substance must
answer positively, as for a materialist personal identity can only consist in identity of life and not substance.  Yet
for those who believe in the existence of an immaterial thinking substance, Locke acknowledges that it depends on
the nature of this substance which is unknown, and whether consciousness can be transferred from one thinking
substance to another.  If so, it is entirely possible that two separate substances can be the same person, as long as
the consciousness is preserved.

In dealing with the second question, as to whether two different persons can share the same thinking substance,
Locke reformulates the question to make the matter clearer: “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 lost 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” (396).  This is an interesting point, as anyone who
believes in the pre-existence of the soul before birth would contend that the person currently alive shares the same
identity with the soul as it existed prior to birth, whether in a previous incarnation or some other form that is no
longer accessible by memory.  Locke gives as an example a man he met who was convinced that his had been the
soul of Socrates, yet Locke asks whether he can really be the same person as Socrates without sharing any of the
same memories.  Locke asks us to suppose that we have the same soul as was in Nestor or Thersites at the siege
of Troy, and then to consider whether we can consider ourselves the same person although we have none of these
memories.  Locke denies that we can, as our concept of a person rests on the sum of his experiences, and in
having cognitive access to none of the experiences of Nestor or Thersites, we cannot consider ourselves to be the
same person even if we share the same soul.  Yet if we are conscious of even one of the actions of Nestor, we
can consider ourselves to be the same person.

Locke defines the
self as “that conscious thinking thing…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….That with
which the consciousness of this present thinking thing
can join itself make the same person, and is one self with it”
(397).  Again we find this definition to be completely independent of substance.  The little finger is very much a
part of the self, as whatever it touches is perceived in thought and is part of one’s consciousness.  Should the little
finger be removed, it is no longer a part of the self because we no longer have conscious control over it, and we
no longer feel what it touches.  However, should the consciousness go with the little finger after its removal, and
we feel
only what the finger touches and have no conscious control over the rest of the body, it is the finger that
constitutes the self.

Personal identity consists only in what can be joined to the same consciousness.  If Socrates does not partake in
the same consciousness while he is awake as while he is asleep, then waking Socrates and sleeping Socrates
ought to be considered two different persons.  The problem that many people would have with this way of
thinking is that we would not normally consider a man, having lost the memory of certain parts of his life beyond
the possibility of ever retrieving them, to be a different person than the man that performed these actions because
it was after all the same man.  Yet Locke insists that because this man has two distinct incommunicable
consciousnesses at different times, this man has been two different persons.  He points out that we do not punish
the mad man for the sober man’s actions, nor the sober man for what the mad man did.  This point addresses the
most important issue regarding the matter of personal identity: the ethical consequence of our definition with regard
to personal responsibility.  For what can we hold a man accountable if a man is no more than what is united to his

Locke puts forward three possibilities of what might be meant by the same individual man: (1) the same individual,
immaterial, thinking substance—the same numerical soul, (2) the same animal with no regard to immaterial soul, or
(3) the same immaterial soul in the same animal.  No matter which definition we use, Locke insists, personal
identity can only consist in consciousness.  By (1), even a man born of different women in distant times can be the
same man, though he would be two different persons.  By (2) and (3) the only way one can be the same individual
man is to have the same individual consciousness, as without regard to soul or if we insist the soul be united to the
same animal there is no difficulty in allowing the same man to be the same person.

One objection that may arise to this way of thinking is that we consider a man to be the same person while drunk
as he is while sober, and the same while he is sleeping as when he is awake.  If a man commits a crime while
drunk or sleep-walking, we hold him accountable even if he has no conscious memory of the event.  Locke insists
that human laws punish the man in these cases because there is no way of knowing whether the lapse in memory is
genuine or counterfeit, as one cannot prove a lack of consciousness.

Two final questions that Locke poses regarding personal identity are “Could we suppose two distinct
incommunicable consciousnesses acting in the same body, the one constantly by day, the other by night; and, on
the other side, the same consciousness, acting by intervals, in two distinct bodies?” (399)  If we go by Locke’s
definition, it is clear that in the first case the day and night man would indeed be two distinct persons, as different
from one another as Socrates and Plato.  And in the second case, there would be one person in two bodies just
as it would be the same person wearing two different sets of clothing.  Locke notes that this being the same
distinct consciousness is in no way dependent on it residing in the same immaterial substance, as personal identity
would be determined by consciousness whether or not it were annexed to such a substance.  “For, granting that
the thinking substance in man must be necessarily supposed immaterial, it is evident that [that] immaterial thinking
thing may sometimes part with its past consciousness and be restored to it again….Make these intervals of
memory and forgetfulness to take their turns regularly by day and night and you have two persons with the same
immaterial spirit, as much as in the former instance of two persons with the same body” (399).  Anything a
substance has thought or done that a person cannot recollect through consciousness does not belong to that
person any more than the thoughts or actions of another person altogether.

The self, according to Locke, is an intelligent being capable of happiness or misery, and
person is the name for
this self.  This is a forensic, or legal, term, and belongs only to intelligent beings capable of law, and happiness and
misery.  The personality extends to the past self by consciousness alone, whereby it becomes accountable to these
past actions.  “And therefore whatever past actions it cannot reconcile or
appropriate to that present self by
consciousness, it can be no more concerned in than if they had never been done: and to receive pleasure or pain, i.
e. reward or punishment, on the account of any such action is all one as to be made happy or miserable in its first
being without any demerit at all” (401).  Thus for Locke, it would be unjust for any man to be punished now for
something his soul had done in a previous life, as this soul is now a part of an entirely different self, and there is no
difference between a punishment for a crime that is beyond recollection and to be created miserable.

As Locke concludes, the difficulty of this matter has to do with the misuse or lack of clarity in the terms we use to
describe it rather than any inherent obscurity in the things themselves.  Questions regarding personal identity or
what constitutes the self are legal questions with consequences in ethics rather than metaphysics.  If I share the
same soul as Socrates, it is really just a matter of choice as to whether I consider myself to be the same “self” or
“person” as Socrates, as these are just words and the identity of my soul remains the same regardless of what sort
of definition I choose to attach to them.  That being said, the words we use and their given definitions do play a
significant role in how we
think about the concepts of self and personal identity.  Should we conclude as Locke
does that self is no more or less than what is united within a single consciousness, we bias ourselves towards
dualism by admitting that one man can be two different persons or that one person can exist in two different men.  
Yet if we tie personal identity to the life of a single animal, we shift this prejudice towards materialism.

It is the ethical consequences of the conceptual framework we choose that is the most important matter here, as
the justice or injustice of being punished for a crime which I do not remember committing
does depend on
whether my self is consciousness only or tied to my soul.  If it is the latter, it could easily be argued that I ought to
be punished for a crime I committed in this lifetime that I do not remember because I am in fact the same person
that I was then and ought not to be allowed to escape justice simply because I had forgotten what I’d done.  The
same argument could be made for my being punished for something I had done in a previous life, as although I
may have had a different personal identity at the time, it is the same inner being that committed the crime and that
still carries the guilt with it.  Though my soul may now have a different body and personality, to argue that it is no
longer responsible for those actions would be akin to saying that I am not responsible for what I did yesterday
because I wore different clothing.  I am inclined to believe that my soul is responsible for what it did in previous
incarnations and that it is perfectly just for me to experience the consequences now though I do not remember
those lives, and therefore I am reluctant to place personal identity, as Locke does, with consciousness alone.  Yet
this is merely a matter of preference with regard to my own ethical opinions, and to adopt Locke’s definition
would not alter my metaphysical beliefs in any way.

On the other hand, if we adopt the materialist view and disregard the belief in immaterial soul altogether, I would
be much more ready to accept Locke’s definition.  When we punish a person for a crime committed, what is it
that we in fact hold responsible if not the person’s soul?  It could not be the physical substance of the body, as if
this were the case we could not prosecute any person for a crime after nine years have passed because not a
single atom in this person’s body is the same as it was then.  Such a criterion is clearly absurd, especially if the
person has a clear memory of committing that crime over nine years ago.  Yet even if the crime was committed
recently, could we justly punish the man if he has no conscious recollection of it?  We have already established
that we are not punishing the physical substance, so it must be that we are holding accountable the motivating
force, whatever that may be, that committed the crime.  Yet if the force that now motivates a person’s actions is
completely distinct from that which committed the crime, though it operates within the same body, it would be
unjust for such a person to receive punishment.

Finally, it must be admitted that the justice or injustice of punishment does not depend on conscious memory
alone.  A criminal may completely repent and reform himself, becoming what could even be called a “new person”
and yet still retain the memories of the crimes he committed, and it could be argued that to punish this person for
the crimes he committed before reforming would be unjust.  The perfect example can be found in Victor Hugo’s
Les Miserables.  In the story, the police inspector Javert is on a crusade to bring the convict Jean Valjean to
justice even though Valjean has completely reformed, because he believes that a person can not change and
remains responsible for his past crimes regardless of what he has done since.  Yet in the end when Valjean has
Javert at his mercy and chooses to let him go free rather than kill him, Javert realises he has been wrong all along,
and unable to bear this realisation that has rendered his entire life meaningless, kills himself.  Although Valjean
remembers his life as a criminal, Javert understands that it is not necessarily just to hold him responsible, as he has
become in every relevant way a different person.

Clearly, questions of personal identity are highly nuanced, and are as difficult to draw concrete lines around as the
ethical questions upon which they directly bear.  No definition can be considered completely wrong or right, as we
are merely defining a term and not speculating as to the concrete nature of reality.  Locke’s definition has strengths
as well as weaknesses, as any definition will.  I would unite personal identity to the soul because I do not believe it
is necessarily unjust to hold a person accountable for an action that he or she does not remember, either in this life
or in another.  If there is no immortal soul I would be much more inclined to tie personal identity to consciousness
because there is nothing else to unite a person now with the person in the past.  In any case, this question may
have no answer but it nevertheless must be addressed because of the important ethical consequences it leads to.