Jeffery wrote:

I want to discuss the anthropic principle in more detail. It might
seem in contradiction with the Copernican principle, which says that
we are typical observers. The anthropic principle says that we aren't
completely typical because we are in a time and place that life would
arise. Otherwise we wouldn't be here. For instance, if you chose a
point in the Universe at total random, it would be very unlikely to be
as close to a star as we are. However, it is not unlikely or
surprising that we are close to a star because life would have to
arise close to a star. In other ways, you can explain why we are at
the time and place we are on the grounds that life would be more
likely to arise at our time and place. For instance, if the Universe
will exist for infinite length of time into the future, then isn't it
surprising that we are only 13.7 billion years after the Big Bang
instead of a googol, 10^100 years, or a googolplex years?

The "Copernican principle"--which wasn't really formulated by
Copernicus, but has been fathered on him--contains zero data, but is a
useful safeguard against *a priori* thinking of a particular (and
currently unfashionable) sort. But that's fighting yesterday's war. A
priori thinking is alive and well, but nowadays it goes in the other
direction. It's still worth resisting it, though.

We live where we live, and we have exactly one data point as to where
observers are likely to be found. A certain modesty is appropriate in
drawing cosmic conclusions from one data point. (Though that seems to
be one more than the string theorists have.) ;-)

It's clearly true that we must live in a place where we could live, and
that this constrains what we could observe, but so what? It's only *a
priori* thinking that has us worried about whether our position is
typical enough. Which is amusing, since that's the sort of thing we
associate with Cardinal Bellarmine, rather than with Galileo.

Reasoning a priori about whether it's likely that we would be found
where we are assumes that we know some ensemble of possible positions
for observers, which we don't, and that we know something about what
kinds of observers could exist, which we also don't. So worrying about
whether some vague grand principle is satisfied appears to be exactly
analogous to the Inquisition's worrying about whether motion is or isn't
repugnant to the motionless nature of the Earth.

Cheers,

Phil Hobbs