First of all, I'm really glad we're having this conversation.

This question is the one philosophical issue that has been bugging me for several years. I read through your post and your comments and felt like someone was finally asking this question in a way that has a chance of being understood well enough to be resolved!

... then I began reading the replies, and it's a strange thing, the inferential distance is so great in some places that I also begin to lose the meaning of your original question, even though I have the very same question.

Taking a step back -- there is something fundamentally irrational about my personal concept of identity, existence and mortality.

I walk around with this subjective experience that I am so important, and my life is so important, and I want to live always. On the other hand, I know that my consciousness is not important objectively. There are two reasons for this. First, there is no objective morality -- no 'judger' outside myself. This raises some issues for me, but since Less Wrong can address this to some extent, possibly more fully, lets put this aside for the time being. Secondly, even by my own subjective standards, my own consciousness is not important. In the aspects that matter to me, my consciousness and identity is identical to that of another. Me and my family could be replaced by another and I really don't mind. (We could be replaced with sufficiently complex alien entities, and I don't mind, or with computer simulations of entities I might not even recognize as persons, and I don't mind, etc.)

So why does everything -- in particular -- my longevity and my happiness matter so much to me?

Sometimes I try to explain it in the following way: although "cerebrally" I should not care, I do exist, as a biological organism that is the product of evolution, and so I do care. I want to feel comfortable and happy, and that is a biological fact.

But I'm not really satisfied with this its-just-a-fact-that-I-care explanation. It seems that if I was more fully rational, I would (1) be able to assimilate in a more complete way that I am going to not exist sometime (I notice I continually act and feel as though my existence is forever, and this is tied in with continuing to invest in my values even though they insist they want to be tied to something that is objectively real) and (2) more consistently realize in a cerebral rather than biological way that my values and my happiness are not important to cerebral-me ... and allow this to affect my behavior.

I've had this question forever, but I used to frame it as a theist. My observation as a child was that you worry about these things until you're in an existential frenzy, and then you go downstairs and eat a turkey sandwich. There's no resolution, so you just let biology take over.

But it seems there ought to be a resolution, or at the very least a moniker for the problem that could be used to point to it whenever you want to bring it up.