True Immortality [was Re: Uploaded memories]

Robert J. Bradbury (
Wed, 8 Dec 1999 03:05:01 -0800 (PST)

On Wed, 8 Dec 1999, Kate Riley wrote:

> Sure, there's no question that the contents of our present memories may be
> stored. The question is what happens a billion years down the road, with a
> billion years worth of memories, at the increased clarity which will most
> likely be desired, with presumably a billion people (more?) drawing on the
> same resources. If we discount terminal entropy, and assume that there is a
> finite amount of matter in the universe, then there logically must be a
> point where all resources will have been consumed. Is there a way to avoid
> this?

I've addressed this in the MBrain architecture in what I call "photon loop" storage. You store the data as circulating photons rather than atoms. You send the photons out to another node in the MBrain (within a solar system), or another MBrain (separated by light years) that receives the data and then regenerates it and sends it back to you. Think of it as a circular recording tape where it takes a long time to get back to the starting point on the tape. The advantage is that a single atom can make many photons.

There is of course a limit to this but we would have to study the problem to see whether it is (a) the matter for generating the photons; (b) the energy contained in the photons; (c) the size of the universe limiting the loop size.

> Will the universe experience heat death before then?

I doubt it. I think we hit the memory limits long before the universe runs down, simply because the expansion is causing matter (& energy) to become increasingly more dilute. Unless we intervene in this process and send all of the matter back to the starting point I think we run out of concentrated energy sources long before heat death.

Interestingly enough, "heat death" (lack of concentrated energy sources) isn't the final stage. In current scenarios, the final stage is "evaporation death" where all that is left is black holes that eventually evaporate. Since "heat" as we know it requires the movement of atoms and atoms don't exist in black holes, I think the use of the word "heat" seems inappropriate. You can take the temperature of space outside the event horizon but I don't believe you can take the temperature of the black hole itself.

> Does this eliminate the possibility for "true" immortality?

The matter (or energy limits) do not limit "true" immortality. They simply sets a limit on your thought granularity. It eliminates the possibility of remembering that you have been saying "Ommmmmmm......" for the last trillion years at femtosecond accuracy, but that doesn't limit you from saying "Ommmmmm....." for a trillion years at milli-second accuracy. As you get older you change your thought granularity size.

The question of "true" immortality is wrapped up in -- whether it is possible to prevent the decay of baryonic matter, whether the universe is open or closed, whether it will expand forever or reverse itself, whether there is a way to tunnel out of the universe and what happens to the information that seems to get lost when it gets swallowed by black holes.

In short the jury is still out, and I suspect will remain out at least until we have a Theory of Everything.

But multi-trillion-year lifetimes (MTYL) seems feasible so you will have plenty of time to think about the problem.