>>12410802 Proposals for describing the initial state of the universe hardly ever address a certain
fundamental issue—yet this is an issue whose significance is, in a certain sense, obvious.
This arises from one of the most fundamental principles of physics: the Second Law
of thermodynamics. According to the Second Law, roughly speaking, the entropy of
the universe increases with time, where the term “entropy” refers to an appropriate
measure of disorder or lack of “specialness” of the state of the universe. Since the
entropy increases in the future direction of time, it must decrease in the past time-
direction. Accordingly, the initial state of the universe must be the most special of all,
so any proposal for the actual nature of this initial state must account for its extreme
specialness. Proposals have been put forward from time to time (such as in various forms
of inflationary cosmology and the previously popular “chaotic cosmology”6) in which
it is suggested that the initial state of the universe ought to have been in some sense
“random”, and various physical processes are invoked in order to provide mechanisms
whereby the universe might be driven into the special state in which it appears actually to
have been in, at slightly later stages. But “random” means “non-special” in the extreme;
hence the conundrum just referred to.
Sometimes theorists have tried to find an explanation via the fact that the early
universe was very “small”, this smallness perhaps allowing only a tiny number of
alternative initial states, or perhaps they try to take refuge in the anthropic principle,
which would be a selection principle in favour of certain special initial states that allow
the eventual evolution of intelligent life. Neither of these suggested explanations gets
close to resolving the issue, however
It may be seen that, with
time-symmetrical dynamical laws, the mere smallness of the early universe does not
provide a restriction on its degrees of freedom.
