>Brian also wrote:
>
>> Again we have to be careful here. In most cases, the fine-tuning
>> results in a Universe in which carbon based life forms can evolve
>> by natural processes. Interestingly enough, most proponents of
>> the design argument based on fine-tuning (in the primary literature)
>> would consider: (a) showing life would arise under suitable prebiotic
>> conditions with probablity near 1 and (b) finding that life is common
>> in the Universe to be a tremendous boost to their design argument.
>
>
>I agree, we need to be careful, cautious, and _consistent_ in our
>arguments about design, fine-tuning, and the Anthropic Principle.
>
John Leslie often discusses inconsistencies in the design argument
based on fine-tuning, perhaps to put off any suspicion that he
might be a creationist :-), for example:
_1. Some Alleged Weaknesses of Design Arguments_
The argument from design tries to prove God's reality by
examining the universe. In the form given to it today by
those naming themselves "creation scientists" it earns the
fury of genuine scientists. I shall show why most reputable
thinkers consider it long dead and buried. But afterward I
plan to demonstrate that recent developments make it very
much alive, though not in any shape creation science would
welcome.
-- Leslie, J. (1985). "Modern Cosmology and the Creation of
Life," in <Evolution and Creation>, Ed. E. McMullin,
University of Notre Dame Press, pp. 91-120.
Loren:
[...]
>Physicists generally expect a more fundamental theory will eventually come
>along, one with fewer "free parameters." If this new fundamental theory
>has just as much "fine tuning" as the standard model, theists won't mind a
>bit. However, most atheists are hoping that the new fundamental theory
>will do one of two things:
>
>1) The new fundamental theory will have very few or no free parameters,
>and the apparent "fine tuning" will simply be the logical consequences of
>any self-consistent theory.
>
>2) The new fundamental theory will predict, as a natural (non ad-hoc)
>consequence, that there are a vast number of causally disconnected
>universes, each with their own set of physical constants.
>
>Suppose one of these two possibilities really does happen? Would it be a
>serious blow to the design-from-fine-tuning argument? Yes. Would it be a
>serious blow to theism? No. (Neither can answer the question of why the
>universe exists at all.) HOWEVER, if we (collectively) put too much
>emphasis on the design-from-fine-tuning argument, we might generate the
>APPEARANCE that theism was harmed.
>
First, I agree with Loren's main point. We have to be very careful
not to paint ourselves into a corner. However, I will argue that
(1) by itself doesn't really counter the fine-tuning argument.
First consider the following comment by Dennis Sciama:
This simple but powerful argument leads us to ask the question:
*how much* can I deduce about the universe from the fact that
I exist? It turns out that various elementary particle, nuclear,
atomic and molecular properties of matter have to be very finely
tuned for conditions in the universe to have permitted my
development--many examples are given by Barrow and Tipler and
elsewhere in this book. These finely tuned properties will
probably also eventually be accounted for by fundamental
theory. But why should fundamental theory _happen_ to lead
to these properties?
There seem to be three possible answers to this question:
(a) It is a complete chance.
(b) God regards me as such a desirable product of the universe
that he has fine-tuned it so as to guarantee my development.
(c) There exist other, disjoint, universes with other laws
and constants of nature.
-- D.W. Sciama, "The Anthropic Principle and the Non-Uniqueness
of the Universe," in _The Anthropic Principle_, Proceedings
of the Second Venice Conference on Cosmology and Philosophy,
F. Bertola and U. Curi, ed., Cambridge University Press,
1993, pp. 107-109.
This is obviously going to be controversial, of course, but according
to Sciama a fundamental theory accounting for all the current
"coincidences" will not get one out of the pickle since one still
has the nagging question: "But why should fundamental theory _happen_
to lead to these properties?"
Sciama's answer to this little problem is to suppose that there
might be an ensemble of different fundamental theories with only
a few yielding finely tuned universes. Then he appeals to
Many Worlds and anthropic selection in the usual way. But what
if there were only one logically possible fundamental theory?
Again, we have a surprise. This turns out to be Sciama's worst
nightmare, since in this case all other universes (assuming
for the moment that they exist) will be identical and every one
will be finely tuned ;-). This being the case, one can no longer
appeal to anthropic selection.
Here's another quote from Carr and Rees along similar lines to
Sciama:
These arguments go a little way towards giving the anthropic
principle the status of a physical theory but only a little:
it may never aspire to being much more than a philosphical
curiosity. One day, we may have a more physical explanation
for some of the relationships discussed here that now seem
genuine coincidences. For example, the coincidence
[alpha_G ~ (m_e/m_p)^8 -- my ascii rendering -- BH], which
is essential for nucleogenesis, may eventually be subsumed
as a consequence of some presently unformulated unified
physical theory. However, even if all apparently anthropic
coincidences could be explained in this way, it would still
be remarkable that the relationships dictated by physical
theory happened also to be those propitious for life.
-- B.J. Carr and M.J. Rees (1979). "The Anthropic Principle
and the Structure of the Physical World," <Nature> 278:605-612.
Finally, here's a lengthy quote from Paul Davies discussing some
of the problems with the Many Worlds theory:
In spite of the apparent ease with which many-universes theory
can account for what would otherwise be considered remarkable
features of the universe, the theory faces a number of serious
objections. Not least of these is Ockham's razor: one must
introduce a vast (indeed infinite) complexity to explain the
regularities of just one universe. This "blunderbuss" approach
to explaining the specialness of our universe is scientifically
questionable. Another problem is that the theory can explain
only those aspects of nature that are relevant to the existence
of conscious life, otherwise there is no selection mechanism.
Many of the best examples of design, such as the ingenuity and
unity of particle physics, have little obvious connection with
biology.
Another point that is often glossed over is the fact that in all
of the many-universe theories that derive from real physics
(as opposed to simply fantasizing about the existence of other
worlds) the laws of physics are the same in all the worlds. The
selection of universes on offer is restricted to those that are
_physically_ possible, as opposed to those that can be imagined.
There will be many more universes that are logically possible,
but contradict the laws of physics. So we cannot account for
nature's _lawfulness_ this way, unless one extends the many-
universes idea to encompass all possible modes of behavior.
Imagine a vast stock of alternative realities for which any
notion of law, order, or regularity of any kind is absent.
Physical processes are entirely random. However, just as a monkey
tinkering with a typewriter will eventually type Shakespeare,
so somewhere among the vast stack of realities will be worlds
that are partially ordered, just by chance. Can anthropic reasoning
be used to conclude that any given observer will perceive an
ordered world, mind-boggling rare though such a world may be
relative to its chaotic competitors? I think the answer is clearly
no, because anthropic arguments work only for aspects of nature
that are crucial to life. If there is utter lawlessness, then
the overwhelming number of randomly selected inhabited worlds
will be ordered only in ways that are essential to the preservation
of life. There is no reason, for example, why the charge of the
electron need remain absolutely fixed, or why different electrons
should have exactly the same charge. Minor variations would not be
life threatening. But what else keeps the values fixed--and fixed
to such astonishing precision--if it is not a law of physics?
One could, perhaps, imagine an ensemble of universes with a
selection of laws, so that each universe comes with a complete
and fixed set of laws. We could then perhaps use anthropic
reasoning to explain at least why some of the laws we observe
are what they are. But this theory must still presuppose the
concept of law, and begs the question of where those laws come
from, and how they "attach" themselves to universes in an
"eternal way."
-- Paul Davies, "The Unreasonable Effectiveness of Science,"
in _Evidence of Purpose_, J.M. Templeton, ed., Continuum,
1994, pp. 44-56.
By way of summary, in my opinion a fundamental theory in the
absence of Many Worlds will not damage the fine-tuning argument
and may actually help it. This leads us to your second point,
which I'll repeat below:
Loren:
>2) The new fundamental theory will predict, as a natural (non ad-hoc)
>consequence, that there are a vast number of causally disconnected
>universes, each with their own set of physical constants.
>
I have to agree that this, if it could be shown, would be pretty
devasting to the design argument, but not necessarily to theism
of course.
Perhaps it is just my prejudice as an experimentalist but I have
a really tough time taking this possibility seriously. First of
all, is it conceivable that a general theory would actually be
able to predict something like this? After all, the other universes
must be causally disconnected. Also, what we currently know and
suspect from chaos theory would seem to cast doubt on the possibility.
And finally, could we really be confident in a prediction that
cannot be tested even in principle?
========================
Brian Harper | "I can't take my guesses back
Associate Professor | That I based on almost facts
Applied Mechanics | That ain't necessarily so"
Ohio State University | -- Willie Nelson
========================