Immortality and memory ‒ Part 1
Many people say they wish to live forever. Whole religions are founded on promising to grant that wish. What would it take to live forever? Physics predicts that, far enough in the future, no macroscopic physical objects will be around. To allow for your endless existence, therefore, we must assume that you’ll continue to exist long after anything that could be called “your body” has stopped existing.
Without a physical body whose spatial location could fix your identity across time, your continuing identity must come entirely from relations among your (nonphysical) mental states, in particular your memories. For you to live forever, the immortal entity must remain the same person as you, which means it must retain enough of your memories. But, as I’ll argue, it can do so only if its existence becomes unbearably boring.
The crucial premise of my argument is that, with or without a body, you can’t possibly store infinitely many memories. However big your memory capacity is or becomes, it will always and essentially remain finite. If you find this restriction unmotivated, consider all the other ways in which you’re essentially finite. You couldn’t have infinite power, like God according to traditional theism. You couldn’t have infinite volume or mass, like the universe according to standard cosmology. You couldn’t have infinite density, like a gravitational singularity according to general relativity. Right now you have those things in finite amounts, and the difference between any finite amount and infinity is a difference in kind, not just degree. Anything infinite in any of those ways must be something other than you. So too with memory.
As an immortal with finite memory capacity, if you form new memories at a nonzero rate, even just one new memory per century, then eventually all your memories of earthly life will be replaced. This inference presumes that new memories will always eventually displace older ones in your finite stock. If they don’t, and you keep some older memories at the cost of losing newer ones, then you’ll have worsening short-term recall, like a demented elderly person who remembers an episode from his youth but nothing about yesterday or last year. Such a disconnected existence is lamentable, so I conclude that in any desirable immortal life new memories eventually displace all older ones.
I’ll discuss some consequences of this result in Part 2 of this two-part series.
