RE: White Rabbit vs. Tegmark

From: Patrick Leahy <jpl.domain.name.hidden>
Date: Wed, 25 May 2005 13:34:01 +0100 (BST)

On Wed, 25 May 2005, Stathis Papaioannou wrote:

<SNIP>
> Consider these two parallel arguments using a version of the anthropic
> principle:
>
> (a) In the multiverse, those worlds which have physical laws and
> constants very different to what we are used to may greatly predominate.
> However, it is no surprise that we live in the world we do. For in those
> other worlds, conditions are such that stars and planets could never
> form, and so observers who are even remotely like us would never have
> evolved. The mere fact that we are having this discussion therefore
> necessitates that we live in a world where the physical laws and
> constants are very close to their present values, however unlikely such
> a world may at first seem. This is the anthropic principle at work.
>
> (b) In the multiverse, those worlds in which it is a frequent occurence
> that the laws of physics are temporarily suspended so that, for example,
> talking white rabbits materialise out of thin air, may greatly
> predominate. However, it is no surprise that we live in the orderly
> world that we do. For in those other worlds, although observers very
> much like us may evolve, they will certainly not spend their time
> puzzling over the curious absence of white rabbit type phenomena. The
> mere fact that we are having this discussion therefore necessitates that
> we live in a world where physical laws are never violated, however
> unlikely such a world may at first seem. This is the *extreme* anthropic
> principle at work.
>
> If there is something wrong with (b), why isn't there also something
> wrong with (a)?
>
> --Stathis Papaioannou

Good point, this is a fundamental weakness of the AP. If you take it to
extremes, we should not be surprised by *anything* because the entire
history of our past light-cone to date, down to specific microscopic
quantum events, is required in order to account for the fact that you and
I are having this particular exchange. To give the AP force, you have to
work on the most general possible level (hence it was a big mistake for
Barrow & Tipler to restrict it to "carbon-based life forms" in their book,
certainly not in line with Brandon Carter's original thought).

Paddy Leahy
Received on Wed May 25 2005 - 08:37:34 PDT