The Problem of Personal Identity
Change & Identity: A Quick Review
Two Views About Change and Sameness (“Identity”):
• Change requires that something become different than it was but difference is the
opposite of sameness so nothing can change and still be the same.
• Materialism (Heraclitus): Nothing stays the same
• Idealism (Parmenides): Nothing changes
• Things can undergo some changes and still remain the same, provided that those are
insignificant and gradual.
• Plato on Body and Soul (p. 34)
• “The soul is the very likeness of the divine, and immortal, and intellectual, and uniform,
and indissoluble, and unchangeable…
• … and the body is the very likeness of the human, and mortal, and unintellectual, and
multiform, and dissoluble, and changeable.”
• Diotima (p. 34): “We assume that a man is the same person in his old age as in his
infancy, yet although we call him the same, every bit of him is different, and every day he
is becoming a new man while the old man is ceasing to exist, as you can see from his
hair, his flesh, his bones, and all the rest of his body.”
• Diotima (p. 34): “And not only his body, for the same thing happens to his soul. And
neither his manners, nor his dispositions, nor his thoughts, nor his desires, nor his
pleasures, nor his sufferings, nor his fears are the same throughout his life.”
The Problem of Personal Identity
Given the many changes we undergo during our lives, what makes each of us numerically the
same persons for the duration of our lives?
1) Bodily Changes
2) Psychological Changes
B. Sameness C. Qualitative Sameness/ Identity
D. Numerical Sameness/Identity
John Locke on Personal Identity (1689):
Persons vs. Human Beings
Identity is Relative (to classification)
Memory Criterion for Personal Identity
“Man” [human being] vs. Person
(1) Human Being: “is nothing else but an animal of such a certain form” (38)
(a) “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 still call him a man [human] a dull irrational man.” (38)
(b) “whoever should hear a cat or a parrot discourse, reason, and philosophize would call or
think it nothing but a cat or parrot … a very intelligent rational parrot.” (38)
(2) Person: “is a thinking intelligent being, that has reason and reflection, and can consider itself
as itself” (39)
John Locke’s definitions:
• Human being is the species
• Person is someone who is able to be aware of its surroundings, conscious.
“consciousness always accompanies thinking, and it is that which makes everyone to be what
he calls self” (39)
Consciousness and Self:
• (3) Consciousness: This is Locke’s term for our awareness of our own thoughts and
All persons think and perceive, but we are, in addition, conscious of that fact about
• (4) Self: ‘it is by this [consciousness] every one is to himself that which he calls self’, and
‘consciousness . . . is that which makes everyone to be what he calls self’.
• John Locke believes that self means that that person who is the self is aware of its
‘Of Identity and Diversity’:
• Identity – one and only one thing can exist in a particular place at a particular time. • Diversity – each thing is distinct from all others by virtue of occupying a particular place
at a particular time.
Identity is Relative:
• “The idea of identity [is] suited to the idea it is applied to” (38)
• Consciousness is the key to a person’s identity for John Locke.
• “[W]e must consider the idea … it [identity] is applied to … it being one thing to be the
same substance, another to be the same man, and a third the same person.” (28)
Is X the same as Y?
• Locke: The question is incomplete, and cannot be answered until we first clarify what we
are asking: Is it the same … WHAT?
• Is X the same parcel of matter as Y?
• Is X the same human being as Y?
• Is X the same person as Y?
• Is X the same ____ as Y?
Rapid and Dramatic Change:
• After Gregor’s transformation, the result is not the same man, nor the same human
• And yet, it was Gregor who awoke: “he found himself transformed”?
• How can it be Gregor? How can it be the same person?
John Locke on Personal Identity:
“In this alone consists personal identity … as far as 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 as
it was then.” (39).
Even total (and rapid) bodily changes are possible while remaining the same person:
- Resurrection in a new body i