Re: personal identity

Hal Finney (
Thu, 8 Jan 1998 10:53:18 -0800

Wei Dai, <>, writes:
> Here is my tentative philosophy of personal identity: anyone who remembers
> being me is me. By "remebers being me" I mean he/she/it has a memory of my
> current thoughts and perceptions from my current perspective.
> Some examples: I am the person typing at this keyboard a second ago, but
> he is not me. If I become unconscious and wake up with total amnesia, the
> person who wakes up is not me. If he recovers his (my) memory, then he is
> me again. A copy of me is me, an upload of me is me, even a simulacrum of
> me made from scratch by a Power is me, as long as it has sufficiently
> authentic memories of being me.

I see a couple of problems. The first is a trivial matter of language.
It is very confusing to write that A is B but B is not A. Normally we
use the term "is" in a symmetrical way. It's not even clear which
way to interpret a question like "are you the same person you were a
second ago?". So you might want to use a different phrasing.

The larger problem is that this seems to over-emphasize the importance of
memory. Our memories are important, but it seems to me that identity
requires more than just remembering. If my mind were invaded tomorrow and
rearranged so that my motivations, beliefs, and desires were completely
different, then I would view the result as a different person even if it
kept all my memories.

I also wonder about the gray areas. I don't remember most days of my
life, so probably on most days I can expect that in the future I won't
remember those days. This would seem to imply that after a few years
I will no longer exist. Supposing I am offered the opportunity for an
immortal lifespan, should I refuse it since I won't remember the present
day after some years? That doesn't seem right.

Maybe you should extend it so that you write A < B to indicate that B
"is" A (e.g. remembers being A), and add as an axiom that A < B and B < C
implies A < C. This way I stay alive as long as each day I remember the
day before, even if after a while I have completely forgotten today.