Harpreet asked:

Can you prove you exist? Can you prove that others exist? Am "I" or "you" defined by essence or by
existence?

============

I think there are two strands to your question; a skeptical one about the existence of minds (including
our own mind) and a more controversial one about personal identity. The first is concerned with
whetherwe exist, the second with what kindof existing things we are.

Do I exist? Descartes suggested that it is particularly senseless to doubt that I exist because doubt
simply confirms that I do — I think therefore I am, as he puts it. Whatever I don'tknow about the
world, I do know that it contains the thinking thing that is me.

The argument is invalid. Descartes shows that there is a thought, not that there is an 'I' thinking it. I
cannot know what 'I' am simply from the immediate awareness of mental states; and I cannot know
from this awareness alone that there is a unitary centre of consciousness to whom these states
belong. In other words, I cannot know how to ascribe thinking to myself on the basis of introspection.

A more fundamental problem with this view is that if I did obtain my concept of myself from
introspection — from 'looking at what goes on in my mind' as it were — then I would need a very
good argument indeed for thinking that the same thing were going on in others. From the fact that the
onlymind of which I have direct knowledge is my own, I would merely suppose that others have
minds. J.S. Mill proposed that one might do this by perceiving the similarities between myself and the
other walking, speaking figures I see, hear and get married to. I can only assume by analogywith my
own case that they have sensations, thoughts and possess minds.

Thus I am supposed to infer from a sequence of phenomena in a single case (mine) to the probable
occurrence of the same phenomena in others. This is problematic because in my case I am
presented with a number of three termed sequences of the character:

*Physical modification

*Conscious Experience

*Bodily movement

Yet the class of three-termed sequences I observe from my own case is small when compared with
the class of sequences which are two-termed as far as I can tell. The number of cases where I do not
perceive feeling or thought intervening between (1) and (3) — i.e. when I see any other member of
the human race — is much greater than the number of cases in which I do (my own phenomenal
world). Thus I should properly regard it as very unlikely that thoughts and feelings intervene between
the embodiment and behaviour of other people that I encounter. As a piece of inductive reasoning the
analogy approach is absurd.

What does it mean to ask whether the figures I see around me have minds? Are these figures
'people'? If so, then it is not an open question as to whether 'people' have minds. An essential
property of personhood includes having a mind. If one were to say that these figures were 'living
human bodies' we should have to ask what a living human body is if notthat of a person. I do not
know how to pick out objects that might not bethe bodies of persons.

The idea of a living human body which might not belong to a person is nonsensical. Peter Strawson
puts the problem like this:

There is no sense in the idea of ascribing states of consciousness to oneself — or at all — unless the
ascriber already knows how to ascribe some states of consciousness to others. So he cannot
(generally) argue 'from his own case' to conclusions about how to do this; for unless he knows how to
do this, he has no conception of his own case.
P.F. Strawson Individualsp. 100ff.

If I do not know how to say that mental predicates are true of others, I do not have a concept of
subjects of experience other than myself. So then I do not have a concept of myself as a subject of
experience. This solution clearly relies on Wittgensteinian doctrines of meaning and reference which I
am not concerned to defend here. But it should be clear that the question 'do other people have
minds' is a meaningless one as it could never be an open question as to whether members of the
class of people have minds.

To come to the third question therefore I think that the identity of a person consists in her essential
properties; I am essentially an animal (a type of physical object). My memories and personality are
not essential to the person I am; the essential properties of the physical object that is me —
necessary for any identity claim — include material cohesion and spatio-temporal continuity, not my
memories or my current attachment to The Chipmunks' Christmas Album.This seems to me a far
more coherent position than the existentialist doctrine that existence precedes essence.

Adam Gatward