Physicist Steven Weinberg has famously made the statement that
"the more the universe seems comprehensible, the more it also seems
pointless". According to this Nobel laureate, what physicists are
discovering through science is "an impersonal world governed by
mathematical laws that are not particularly concerned with human beings, in
which human beings appear as a chance phenomena." But if Weinberg
interprets the mathematical "laws of nature" as having nothing to do
with human beings, others have a different interpretation. An increasing number
of physicists see these very laws as "finely tuned" to allow for the
emergence of life. This view is known as the "anthropic principle".
The idea of the anthropic principle was introduced in an
influential book of the same name by physicists John Barrow and Frank Tipler.
The essence of the idea lies in the fact that when physicists look at the basic
physical laws of nature, and at of the basic physical constants, what they find
is that many of these laws and constants seem to be remarkably finely balanced
in such a way as to make life possible. One simple example of this is the laws
of gravity and electromagnetism.
All three of the gravitational, electric, and magnetic forces
obey "inverse square laws" - that is the force of attraction or
repulsion between two such bodies, falls off by the reciprocal of the square of
the distance between them. [The force is proportional to 1/d2.] Now
it happens to be the case that if the force-distance relationship was anything
other than an inverse square law then solar systems and atoms would not be
stable. If the gravitational force was any stronger, stable solar systems could
not form because planets would quickly spiral into the sun. Likewise, if the
electric force was any stronger, stable atoms could not form because electrons
would spiral into the nucleus. Similarly if the gravitational force was any
weaker, planets would tend to drift off into space and not remain in orbit. So
it seems that the inverse square law is particularly fortuitous. It not only
allows the formation of atoms (which are clearly essential for the evolution of
life), it also allows the formation of solar systems to provide nice safe homes
for living beings.
It turns out that the universe is full of examples like this,
where the very nature of a physical law, or the very value of some crucial
physical constant (such as the proton to electron ratio) seems to be fortuitous.
Any change in its value would seem to throw the structure or stability of the
universe so out of kilter that it is hard to see how life could ever evolve in
such a universe. To physicists such as Barrow and Tipler this implies that
something has carefully "tuned" the laws of nature so that life would
evolve. To these scientists, the very laws of nature which Weinberg sees as
purely impersonal, suggest the presence of a thoughtful intelligence acting
behind the scenes - an entity that in some sense "wanted" beings like
us to evolve.
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| Contributed by: Margaret Wertheim