UD is the Universal Distribution, which assigns measure to information
objects as the fraction of computer programs which output them on a
given Universal Turing Machine. (I know I promised to use UDist for
this acronym but I couldn't resist the title I chose.)
ASSA is the Absolute Self Selection Assumption, which says that we
should reason as though we are randomly selected observer moments (OMs).
Combining the UD+ASSA means that the OMs should be selected according
to the Universal Distribution.
QTI is the Quantum Theory of Immortality, which says that in a
many-worlds or multiverse model, each of us will experience immortality
with certainty, because our deaths in some worlds will not affect the
fact that we live on in others.
The DA is the Doomsday Argument, which says (among other things) that
the human race will not greatly increase in numbers beyond its present
day size, because otherwise the chances that we would find ourselves
so early in its history are insignificant.
Here is an idea to tie these together. Some time back [1] I proposed
that the measure of observer-moments would be amplified for those OMs
which were remembered. Most OMs exist only transiently and are forgotten,
but certain ones are special, make an impression, and are remembered for
hours, days or even years. The measure of such OMs is arguably greater
than the ones which are forgotten because of this effect.
Let us assume that this is true and that in fact it can be a very
strong effect, such that remembered OMs may acquire far more measure
than forgotten ones. Then what does that suggest for the DA and QTI?
One way to state the DA, using ASSA concepts, is to start with the
supposition that the human race actually will vastly increase its numbers,
perhaps spreading throughout the entire universe. Then we have to
ask the question, how could it be that we are so early in its history?
In measure terms, the total measure of late observer moments is vastly
greater than the total measure of OMs as early as ours, so the odds are
overwhelmingly against these OMs being experienced.
Just as we accept the low measure of Flying Rabbit OMs as explaining
the lawfulness of the universe, we should accept this way of expressing
the DA as showing the contradiction in assuming that the human race
will grow enormously. That is the conclusion of the DA, which some
find paradoxical.
The resolution could be to suppose that as the human race spreads,
somehow it will retain a memory of its youth. The OMs that we are
experiencing today will echo through time and gain measure in that way,
via the remembering effect I discussed above. It could happen as literal
memories, if we assume that somehow we will become personally immortal and
create copies of ourselves who will spread throughout the universe and
share in the vastening of the human race. Or perhaps a similar measure
amplification effect could occur more indirectly; perhaps our mere
influence on future events could leave sufficient traces down through
time that present day OMs have much larger measure than future ones
(on a per-OM basis). This would allow our present-day existence to be
consistent with even a great vastening of humanity, resolving the DA.
A similar argument might apply to the QTI. In ASSA terms, the
conventional QTI does not work because the measure of extremely old
versions of people is very small, so they would not be very prominent
in the multiverse, any more than inhabitants of Flying Rabbit worlds.
However, if the memory-amplification effect holds, then there could be
a similar phenomenon to QTI.
If we suppose that somehow certain people are destined for immortality,
then the measure of even their young-age OMs would be greatly increased
relative to their fellows by virtue of memory amplification. This would
mean that those of us who are fortunate enough to have such destinies
(which is not completely impossible today, given the progress of medical
technology), would have very high-measure OMs.
This implies that the experience of being a person is prima facae evidence
that he may expect a much longer than usual life span, perhaps even an
immortal existence. Such lucky individuals would have so much higher
measure OMs even in their youth (due to memory amplification) that a
randomly selected OM would very plausibly be that of such an individual.
And the fact that we are young and not super-old is perhaps consistent as
well, since younger OMs would have more memory amplification, both due
to the fact that early experiences have more inherent distinctiveness
and novelty because of youth, and due to the additional years they have
to be remembered and for the echo effect to produce measure amplification.
In short, finding onesself to be young is not necessarily an argument
against this variant of the QTI, and may in fact be considered evidence
in favor of a long or even immortal life span.
Hal Finney
[1] Near the end of
http://www.escribe.com/science/theory/m6905.html
Received on Fri Jul 29 2005 - 01:58:43 PDT