Re: The Great Filter
Thu, 22 Aug 96 22:56:36 GMT

The new version of Robin Hanson's paper is great improvement
over the earlier version I read about a week ago, which
itself was interesting enough. Now it is one of the most
stimulating transhumanist documents I've read.

Here are some more comments.

>That is, if the expected time for some step on any
>one planet is many trillions of years, they why would it
>happen on Earth in only a few
>hundred million years? After all, and the oldest known
>stars are now 15 billion years old, our
>sun would seem to have another five billion years of life
>left, and yet the longest known
>evolutionary step (from simple to complex cells) only took
>about 1.7 billion years.

1.7 billions years does not seem a remarkably short time to
me, even is this context. But this speed argument, as you
recognise, is much stronger against a position that would
place the filter somewhere later in development, say between
primitive mammals and us.

>Another way to explain highly improbable quick change would
>be to assume some special
>temporal window of opportunity. If, for example, our Earth
>is destined to be fried soon by a
>runaway greenhouse effect

But I don't think an explanation is needed here. If this
line of reasoning were correct, and if its assumptions are
granted, then it would imply that there probably is a
temporal window of opportunity and that by now we are
creeping close to the far part of its frame. While such a
conclusion might follow form other considerations in your
article, I do not think that the figure 1.7 years gives it
significant support. For the an impending deadline would
only reduce the potential extent of the window by a small
factor. The reason is that even if no special surprise
effect like a runaway greenhouse effect in the near future
is forthcoming, the earth will become inhabitable within a
few billion years anyway due to increase in solar activity.
So if the "highly improbable quick change" is improbably
quick relative to a window of 4 billion years (runaway
greenhouse effect), it would be not much more improbably
quick relative to a window of, say, 7 billion years. But, as
you yourself note, 1.7 billion years is not improbably quick
given that the event should happen at all during our planets
life time.

>There are also three "save stellar appearances"
>astrophysics alternatives which could explain
>why an apparently dead universe is really alive, with our
>system an isolated "zoo".

>First, large-scale engineering such as Dyson spheres and
>stellar disassembling, might be
>effectively impossible, explaining why nearby stars look so

That does not sound extremely unlikely. It must be combined
with either the assumption that we live zoo, or the
assumption that large scale space travel is also practically
impossible (which looks like a slightly stronger assumption
than that large-scale engineering can't be done).

>I personally think that most of the Great Filter is most
>likely to be explained by the steps I
>think we understand the least about: the early steps in the
>evolution of life and tool-using

The early steps in evolution leave room for hope. But the
evolution of tool-using intelligence happened so quickly
that the speed argument applies and indicates that that step
is not very hard.

>And even if a one-time event did
>select for low colonisation tendencies, we would expect
>stronger tendencies to eventually be
>selected back.

One must be careful, though, not too neglect the possibility
that new technologies might make a social structure
incomparably more stable than any we have seen in history;
and in a certain societies colonisation tendencies would b e
systematically suppressed.

>My personal
>opinion is that we should have the least confidence in our
>estimates of the first steps in
>evolving life, and so these are more likely to be large
>sources of the Great Filter than, for
>example, apparently unlikely social theories. Mars life or
>dark matter evidence could
>dramatically change this situation, however.

I don't directly disagree with this, but it seems to me that
you might have slightly too much confidence in the ability
of the social sciences to tell us what would happen under
conditions radically different from anything that has
occurred so far. With >AI and direct access to our
motivation centres, the psychological mechanisms behind
sociological phenomena would be totally novel; and we should
not simply assume that a social theory that appears unlikely
under present conditions could not be a plausible candidate
for describing a posthuman society (similar arguments have
been made by Wiik, Anders, David Pearce and others). Each
sociological principle that is to be transferred from now to
then requires special justification.

Nicholas Bostrom