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	There have been some inquiries about the anthropic principle.
Recently I read "The Anthropic Cosmological Principle", by John D.
Barrow and Frank J. Tipler, Oxford University Press, 1986.  If you want
to learn about the subject, this is the book to read.  However I must
warn you that the style is turgid, that a substantial degree of scientific
literacy is required, and that the conclusions and arguments are often
dubious.  It is not an easy read for the informed layman.

	The anthropic principle comes in two flavors, the weak anthropic
principle, and the strong anthropic principle.  The following definitions
are from TACP:

Weak Anthropic Principle:  The observed values of all physical and comso-
logical 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 by the requirement that the Universe be old enough for
it to have already done so.

Strong Anthropic Principle:  The Universe must have those properties which
allow life to develop within it at some stage in its history. (Carter)

Participatory Anthropic Principle: Observors are necessary to bring the
Universe into being.  (Wheeler)

Final Anthropic Principle:  Intelligent information-processing must come
into existence in the Universe, and, once it comes into existence, it will
never die out.

	The WAP is not, as it might seem, simply a tautology.  It does
allow us to account for some the observed properties of the universe.
For example, the observed age of the universe can be predicted from the
fact that we exist.  This is turn accounts for many of the "large number"
coincidences.  There is an extensive analysis which indicates that the
various physical constants must be fairly close to their observed values.
The WAP can be taken as a useful heuristic for those concerned with
speculative cosmology.

	The various forms of SAP are more speculative, to put it politely.
Wheeler's arguments are based on QM considerations that I do not feel
competent to evaluate.  In the book the FAP is combined with a lot of
heavy duty cosmology to build some of the most grandiose castles in the
air since Olaf Stapledon.

	Tipler is noted for arguing that We Are Alone; that we are the
only intelligent species in this Galaxy, and probably in the entire 
universe.  A notable fraction of the book is spent on this theme.  I
suspect that this is simply a matter of Tipler working his favorite
hobby horse, since I did not see where any essential connection was made
between We Are Alone and the Anthropic Principle.

	TACP cites a number of evolutionary theorists to claim that 
the develop of intelligence is inordinately improbable.  The arguments
given are mostly a misuse of quotation.  There is an extended discussion
of Tipler's "Von Neumann Machine Dispersion" argument.  (Tippler assumes
the possiblity of AI type Von Newmann machines  -- he does not seem to
recognize that this is not essential to his argument; an intelligent
species constitutes a collection of Von Neumann machines in their own
right.)  Tippler's general argument is important in analyzing the Fermi
Silence question; however it is much less conclusive than he believes.

	There is an interesting argument by Carter which is presented.
Briefly, if the development of intelligent life depends on several
very improbable steps, then it will, with high probability, appear
shortly before the end of the window of opportunity.  This provides
the prediction that, if we don't do something about it, that Earth will
cease to be a hospitable environment for land based life in a few 
hundred million years (or less).  One of the possibilities suggested
is that the atmospheric Oxygen level will rise to too high a level.
Carter's arguments have some major holes; however they do provide
a falsifiable prediction.

	There is an extensive discussion of various teleological 
principles that have appeared in different theologies and cultures.
It should be noted that these are not the same animal as the SAP.

	In summary, the WAP is a useful heuristic whose value is
overstated in the book.  The SAP is interesting, but it and the
speculations derived from it are decidedly premature in view of our
present stage of knowledge about the universe.
-- 

Richard Harter, SMDS Inc. [Disclaimers not permitted by company policy.