Atheism and Theism JJ Haldane - Common Sense Atheism

16 J.J.C. Smart
that would enable them to guess what ‘+’ and ‘=’ mean. We could also give
them a clue to our decimal notation by sending such things as ‘7 + 5 = 12’
(with, say, dot notations for 7, 5, 1 and 2). Now if the extraterrestrials
received a piece of discourse containing ‘1836’ they would guess that the
discourse had something to do with protons and electrons. The pure numbers
are of cosmic interest, unlike the impure numbers such as 12.5 kilograms,
which are terrestrial and conventional. Sometimes the pure numbers are
defined in more complicated ways, as with the fine structure constant, which
determines the strength of electromagnetic interactions relative to those that
explain the other fundamental forces of nature. The ‘fine tuning’ consists in
the relative values of the fundamental constants of physics (constants determined
in the end by pure numbers) being in certain ratios to one another.
Slight differences in any of these ratios would lead to a universe very different
from that which actually exists. 25
In particular, life as we know it could not have emerged, and without life
there could not have been observers. This has led to some curious reasoning
in connection with the so-called ‘Anthropic Principle’ in cosmology. For the
moment I shall ignore the possibility of life as we don’t know it, for example
in an environment of ammonia instead of oxygen, or life that is silicon-based
(instead of carbon-based), or life in a dust cloud, such as in Fred Hoyle’s
science fiction novel The Black Cloud. 26 Now, the proposition that the universe
we observe is such as to contain observers is as it stands tautologous and
utterly uninformative. What is informative comes from propositions about
the fine tuning which seems to be necessary for the universe to allow for the
evolution of galaxies, stars, planets, life, and ultimately observers and theoreticians.
The tautologous proposition obviously cannot explain anything but it
can draw our attention to interesting facts. If we could show that galaxies,
stars, planets, carbon-based life and observers could not exist unless certain
relations held between the fundamental constants of physics, we could deduce
that these relations do exist. Initially, however, the facts about the ‘fine tuning’
are known independently, and then we see how necessary they are for a
universe like ours, and hence for us to be here to know it. Much of it is
necessary for there to be, say, stars. So there could be a ‘stellar’ principle no
less than an ‘anthropic’ one. Also there may possibly be intelligent beings very
different from us humans all over the universe, on planets of distant stars.
Indeed Brandon Carter, who introduced the term ‘Anthropic Principle’, has,
I think, come to dislike the choice of terminology.
Does the fact that if it were not for the fine tuning we would not be here
to know it explain the fine tuning, as some incautious purveyors of the anthropic
principle have at least seemed to suggest? Surely not. It is the fine tuning that
(partially) explains the existence of observers, not the existence of observers
that explains the fine tuning.