Re: [asa] Critique of anthropic principle

From: David Campbell <>
Date: Mon Apr 21 2008 - 12:11:55 EDT

Although I'm not overly enthusiastic about fine-tuning arguments, I
think your comments on the arguments are on target.

> We do not know what fundamental conditions would rule out any possibility of
> any life. For all we know, there might be intelligent beings in another
> universe arguing that if fundamental constants were only slightly different,
> then the absence of free quarks and the extreme weakness of gravity would
> make life impossible.
> [This seems to be an argument from ignorance. There might be other
> intelligent beings and might be other universes, but the counter-argument
> fails for lack of any evidence.]

Yes-although science fiction writers can suggest possibilities like a
hyperintelligent shade of blue, it's open to question whether such
options are very plausible or meaningful (although God, angels, etc.
represent a rather different sort of life to carbon-based life forms).
 On the other hand, we do not know for certain what range of possible
options would function for life-especially a problem for the
"specified complexity" type of argument. It's hard to disagree that
some sort of stable system including a very long-term energy source
(such as stable orbits of planets around stars) is necessary to life,
but it's highly questionable whether the exact set of genes that does
a particular task are required for the task.

> Indeed, many examples of fine-tuning are evidence that life is fine-tuned to
> the cosmos, not vice versa. This is exactly what evolution proposes.
> [I don't understand this argument, and it's simply given as an assertion.
> How is life fine-tuned for the universe, and what does this have to do with
> evolution?]

Natural selection involves the constraints imposed by the environment
on organisms. If a life form is functional enough to survive and
reproduce in a given setting in a particular universe, it can succeed;
if not, it can't. This is the answer to "where does the information
come from in evolution?" It's already there in the environment (with
the caveat that parts, especially the biological portion, of the
environment are also actively changing). Organisms must conform to
their environment. Nevertheless, it's hard to see how any life could
conform to certain environments.

> 2. If the universe is fine-tuned for life, why is life such an extremely
> rare part of it?
> [Again, an argument from ignorance, since we don't know whether or not there
> is life in any other solar system, or even on any other planet. It may have
> relevance since we don't think there is life elsewhere in our solar system,
> but we are such a small part of the universe, I don't see this as a credible
> argument.]

Also, this (and multiverse arguments) could be turned around to claim
that the rarity of life shows just how precise the fine tuning must be
to produce even one planet with life.

> 5. If part of the universe were not suitable for life, we would not be here
> to think about it. There is nothing to rule out the possibility of multiple
> universes, most of which would be unsuitable for life. We happen to find
> ourselves in one where life is conveniently possible because we cannot very
> well be anywhere else.
> [Multiple universes are unproven. If we weren't here, but some other
> intelligent being somewhere else in the universe were pondering this
> question, what difference would it make? This is dodging the question.]

Also, on what basis is it said that "most" of the multiverses would be
unsuitable for life? How do we know that any of them would be
suitable for life, except for ours, which could have highly unusual
deviations from all the others? Either direction is argument from

> 6. Intelligent design is not a logical conclusion of fine tuning. Fine
> tuning says nothing about motives or methods, which is how design is
> defined. (The scarcity of life and multi-billion-year delay in it appearing
> argue against life being a motive.) Fine-tuning, if it exists, may result
> from other causes, as yet unknown, or for no reason at all (Drange 2000).
> [Argument from ignorance, and changing the subject. Fine-tuning anthropic
> arguments don't claim to answer questions of methods or motives, only
> providing a justification for the belief that life was intended.]

Scarcity of life (if true) and multi-billion year delay (although
probably necessary for life in order to have a few rounds of heavy
element generation in supernovae) suggest, but do not prove, that life
is probably not the sole motive. It could be a significant motive,
but balanced with other considerations.

Dr. David Campbell
425 Scientific Collections
University of Alabama
"I think of my happy condition, surrounded by acres of clams"
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Received on Mon Apr 21 12:12:59 2008

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