Cryonics appears to be the best hope for continuing a person's existence beyond physical death until other technologies provide better solutions. But despite its best-in-class status, cryonics has several serious downsides.
First and foremost, cryonics is expensive—well beyond a price that even a third of humanity can afford. Economies of scale may eventually bring the cost down, but in the mean time billions of people will die without the benefit of cryonics, and, even when the cost bottoms out, it will likely still be too expensive for people living at subsistence levels. Secondly, many people consider cryonics immoral or at least socially unacceptable, so even those who accept the idea of cryonics and want to pursue taking personal advantage of it are usually socially pressured out of signing up for cryonics. Combined, these two forces reduce the pool of people who will act to sign up for cryonics to be less than even a fraction of a percent of the human population.
Given that cryonics is effectively not an option for almost everyone on the planet, if we're serious about preserving lives into the future then we have to consider other options, especially ones that are morally and socially acceptable to most of humanity. Pushed by my own need to find an alternative to cryonics, I began trying to think of ways I could be restored after physical death.
If I am unable to preserve the physical components that currently make me up, it seems that the next best thing I can do is to record in some way as much of the details of the functioning of those physical components as possible. Since we don't yet have the brain emulation technology that would make cryonics irrelevant for the still living, I need a lower tech way to making a record of myself. And of all the ways I might try to record myself, none seems to better balance robustness, cost, and detail than writing.
At first this plan didn't feel like such a winner, though: How can I continue myself just through writing? Even if I write down everything I can about myself—memories, medical history, everything—how can that really be all that's needed to restore me (or even most of me)? But when we begin to break down what writing everything we can about ourselves really gives us, writing ourselves into the future begins to make more sense.
For most of humanity, what makes you who you are is largely the same between all people. Since percentages would make it seem that I have too precise an idea of how much, let's put it like this: up to your eyebrows, all humans (except those with extreme abnormalities) are essentially the same. Because we share the same evolutionary past as all of our conspecifics, the biology and psychology of our brains is statistically the same. We each have our quirks of genetics and development, but even those are statistically similar among people who share our quirks. Thus with just a few bits of data we can already record most of what makes you who you are.
Most people find this idea unsettling when they first encounter it and have an urge to look away or disagree. "How can I, the very unique me, be almost completely the same as everyone else?" Since this is Less Wrong and not a more general forum, though, I'll assume you're still with me at this point. If not, I recommend reading some of the introductory sequences on the site.
So if we begin with a human template, add in a few modifiers for particular genetic and developmental quirks, we get to a sort of blank human that gets us most of the way to restoring you after physical death. To complete the restoration, we need to inject the stuff that sets you uniquely apart even from your fellow humans who share your statistically regular quirks: your memories. If the record of your memories is good enough, this should effectively create a person who is so much like you as to be indistinguishable from the original, i.e. restore you.
But, you may ask, is this restoration of you from writing really still you in the same way that the you restored from cryonics is you? Maybe. To me, it is. Despite what subjective experience feels like, there doesn't seem to be anything in the brain that makes you who you are besides the general process of your brain and its memories. Transferring yourself from your current brain to another brain or a brain emulation via writing doesn't seem that much different from transferring yourself via neuron replacement or some other technique except that writing introduces a lossy compression step, necessitated only by a lack of access to better technology. Writing yourself into the future isn't the best solution, but it does seem to be an effective stopgap to death.
If you're still with me, we have a few nagging questions to answer. Consider this an FAQ for writing yourself into the future.
How good a record is good enough? In truth, I don't think we even know enough to get the order of magnitude right. The best I can offer is that you need to record as much as you are willing to. The more you record, the more there will be to work with, and the less chance there will be of insufficient data. It may turn out that you simply can't record enough to create a good restoration of a person from writing, but this is little different from the risk in cryonics of not being well preserved enough to restore despite best efforts. If you're willing to take the risk that cryonics won't work as well as you hope, you should be willing to accept that writing yourself into the future might not work as well as you hope.
How is writing yourself into the future more socially acceptable than cryonics? Basically, because people already do this all the time, although not with an eye toward their eventually restoration. People regularly keep journals, write blogs, write autobiographies, and pass on stories of their lives, even if only orally. You can write a record of yourself, fully intending for it to be used to restore you at some future time, without ever having to do anything that is morally or socially unacceptable to other people (at least, for people in most societies) other than perhaps specify in your writing of yourself that you want it to be used to restore you after you die.
How is writing yourself into the future more accessible to the poor? If a person is literate and has access to some form of durable writing material, they can write themselves into the future, limited only by their access to durable writing material and reliable storage. Of course, many people are not literate, but the cost of teaching literacy is far lower than the cost of cryonics, and literacy has other benefits beyond writing yourself into the future, so it's an easy sell to increase literacy even to people who are opposed to the idea of life extension.
Will the restoration really be me? Let me address this in another way. You, like everything else, are a part of the universe. Unlike what we believe to be true of most of the stuff in the universe, though, the stuff that makes up what we call you is aware of its existence. As best we can tell, the way that you are aware of your existence is because you have a way of recalling previous events during your existence. If we take away the store and recall of experience, we're left with some stuff that can do essentially everything it could when it had memory, but will not have any concept of existing outside the current moment. Put the store and recall back in, though, and suddenly what we would recognize as self-awareness returns.
Other questions? Post them and I'll try to address them. I have a feeling that there will be some strong disagreement from people who disagree with me about what self-awareness means and how the brain works, and I'll try to explain my position as best I can to them, but I'm also interested in any other questions that people might have since there are likely many issues I haven't even considered yet.