Selection Effects
It would be evidence for a
benevolent designer if life were better than could be expected on other
grounds, including anthropic grounds. A
certain capacity for joy would naturally evolve through natural selection, as
an incentive to animals who need to eat and breed in order to pass on their
genes. It may not be likely that
evolution would produce animals who are fortunate enough to have the leisure
and the ability to do science and think abstractly, but our sample of what is
produced by evolution is very biased, by the fact that it is only in these
fortunate cases that there is anyone thinking about cosmic design. Astronomers call this a selection
effect. (Astronomers like Sandra Faber
have to worry continually about selection effects of one sort or another.) The universe is very large, and it should be
no surprise that, among the enormous number of planets that support only
unintelligent life and the still vaster number that cannot support life at all,
there is some tiny fraction on which there are living beings who are capable of
thinking about the universe, as we are doing here. The real question is, whether life is better than would be expected
from what we know about natural selection, taking into account the bias
introduced by the fact that we are thinking about the problem.
This is a question that
everyone will have to answer for themselves.
Being a physicist is no help with questions like this, so I have to
speak from my own experience. My life
has been remarkably happy, probably in the upper 99.99 percentile of human
happiness, but even I have seen a mother die painfully of cancer, a father's personality
destroyed by Alzheimer's disease, and scores of second and third cousins
murdered in the Holocaust. Signs of a
benevolent designer are pretty well hidden.
The prevalence of evil and
misery has always bothered those who believe in a benevolent and omnipotent
God. Sometimes God is excused by
pointing to the need for free will.
Milton gives God this argument in Paradise
Lost:
I formed them free, and free
they must remain
Till they enthral
themselves: I else must change
Their nature, and revoke the
high decree
Unchangeable, eternal, which
ordained
Their freedom; they
themselves ordained their fall.
It seems
a bit unfair to my relatives to be murdered in order to provide an opportunity
for free will for Germans, but even putting that aside, how does free will account
for cancer? Is it an opportunity of
free will for tumors?
It is not necessary for me
to argue here that the evil in the world proves that the universe is not
designed, but only that there are no signs of benevolence that might have shown
the hand of a designer. But in fact the
perception that God cannot be benevolent is very old. Plays by Aeschylus and Euripides make a quite explicit statement
that the Gods are selfish and cruel, though they expect better behavior from
humans. God in the Old Testament
demands of us that we be willing to sacrifice our children's lives at His
orders, and the God of traditional Christianity and Islam damns us for eternity
if we do not worship him in the right manner.
Is this a nice way to behave? I
know, I know, we are not supposed to judge God according to human standards,
but you see the problem here: if we are
not yet convinced of His existence, and are looking for signs of his
benevolence, then what other standards can
we use?
Contributed by: Dr. Steven Weinberg
|
