Re: The Anthropic Principle Boundary Conditions

From: Brent Meeker <meekerdb.domain.name.hidden>
Date: Tue, 23 May 2000 21:03:41 -0700

On 23-May-00, Russell Standish wrote:
> GSLevy.domain.name.hidden wrote:
>>
>> The Anthropic principle has been discussed numerous times before. There are
>> many versions going around. I just want to make a point which I think is
>> crucial.
>>
>> First let me state some of these principles quoted from Barrow and Tipler
>>
>> Weak Anthropic Principle (WAP): The observed values of all physical and
>> cosmological quantities are not equally probable but they take on values
>> restricted by the requirement that there exist sites where carbon-based life
>> can evolve and the requirement that Universe be old enough for it to have
>> already done so.
>> [Barrow and Tipler are not explicit, but this principle implies the requires
>> the existence of conscious observers.]
>>
>> Strong Anthropic Principle (SAP): The Universe must have those properties
>> which allow life to develop within it at some stage in its history. [The
>> emphasis here is on the world "must" which implies that the Universe is the
>> way it is by design.. at least this is the way most people interpret this.
>> This version implies the existence of a creator. Its religious connotations
>> makes it unscientific]
>
> It may be commonly interpreted this way, but I would disagree that it
> should be. In my Occam paper I mention that the SAP implies either a
> Divine creator, or a Plenitude (ensemble). I vaguely remember someone
> raising a third possible implication, although for the life of me I
> can't remember what.
>
> The WAP is simply a consistency statement, that should be true
> regardless of what you believe. I think it is quite true to say that
> assuming an ensemble explanation (pick your favourite Plenitude here),
> the SAP and the WAP are one and the same thing. Therefore I go on to
> use the AP without qualification.
>
> As for the following two APs, I think you have adequately dealt them
> enough damage in order for us to ignore them.
>
I completely agreed with what George wrote and I thought is a good summary. It
seems to me that an ensemble theory implies that there must be a universe with
"us" or "I" in it only if it is known that such a universe is possible. I
don't think we know that such a universe is possible, except for the fact that
we seem to be in one. This is another application of the WAP. So I don't
think that ensemble theory, absent some argument for life from first
principles, adds any more necessity to the universe than already provided by
the WAP.

Brent Meeker
Received on Tue May 23 2000 - 22:10:00 PDT