First, in saying that "I would not ... accept the cosmological argument
as a PROOF of the existence of God," I was simply clarifying my own position
and did not intend to imply that I was necessarily contradicting Glenn (or John
McKiness) on this issue. I am glad to see that Glenn agrees with me that the
Big Bang is not a proof.
Second, an infinite age for the universe does not imply the Eternal
Return. I think Frank Tipler (who does do some sensible stuff --- I just
corresponded with him yesterday about a paper he sent me on "Quantum
Nonlocality Does Not Exist," which I almost entirely agree with, despite my
disagreement with the conclusions of his rather awful book) is right in
pointing out (in writings other than what was quoted) that in classical general
relativity the Eternal Return generically cannot occur, even if the universe is
infinite in time. Even if gravity did not exist, and one had just
nongravitational field theory in Minkowski spacetime, the phase space is
infinite, because of the infinite spatial volume, even at finite total energy,
so one of Nietzche's assumptions would be wrong and there would generally not
be any Eternal Return. Instead, fields would generically just disperse over
time and could only be concentrated into a finite spatial region for a finite
time.
Third, I think Tipler is right in saying "Actually, in his 'proof,'
Nietzsche does not really need to rule out 'creation' he just needs to rule out
the idea that the universe has existed for only a finite time." In other
words, Tipler correctly recognizes that God could have created a universe of
infinite age.
Fourth, I agree with Glenn when he says, "If the Universe is described
by a universal quantum state, then the universe today along with the universe
having the identical quantum state billions of years ago, would also be
indistinguishable from ours. They would have to be indistinguishable universes
as the particles are the indistinguishable. And you would be in that universe
also." (At least I agree if I accept the existence of time, though remember
that it may be just an approximate concept, so that there might not be any
absolute sense in which one can say the universe today is the same as it was
billions of years ago.) But for the moment accepting a classical concept of
time, Glenn is saying that the quantum state of the universe could repeat. If
it evolves by a Schroedinger equation with a time-independent Hamiltonian, it
would keep repeating in a periodic manner. This would just say that the state
would be composed purely out of energy eigenstates that are multiples of
Planck's reduced constant, h-bar = h/(2 pi), divided by the time period. In
other words, the quantum state would then be composed of one or more energy
eigenstates in which the energy eigenvalues are all commensurate, rather than
any irrational ratios of energies occurring.
Although such a periodic quantum state would presumably not be generic
(at least if the Hamiltonian has a continuous spectrum), if time really were
well defined, and if our universe were asymptotically flat (say at distances
beyond what we can see), so that it could have a finite energy, I know of no
evidence that would rule out such a periodic quantum state composed purely of
commensurate energy eigenstates. In fact, the energy superselection rule would
allow it to be in a single energy eigenstate, as William K. Wootters and I
pointed out in "Evolution without Evolution: Dynamics Described by Stationary
Observables," Phys. Rev. D27(12), 2885-2892 (1983). The period for the quantum
state could be arbitrary, possibly billions of years, or possibly a tiny
fraction of a second. (Actually, the period could be long only if the state
were a superposition of commensurate energy eigenstates with the least common
divisor of the energy eigenvalues being an extremely tiny energy, but if the
state were an energy eigenstate, its period would be h-bar divided by the
energy. Taking the rest mass energy of the roughly 10^22 stars in the
observable universe as a lower bound on the energy would give an upper bound of
the period for a single energy eigenstate as less than 10^{-103} seconds, a
decimal point followed by 102 zeroes before the digit one!)
Fifth, if the universe is periodic in time (which I doubt, because I
doubt that it is asymtotically flat as would apparently be needed in order for
its energy to be well defined, but which might be the case without any untoward
observational consequences), I see no reasons to accept Nietzsche's
conclusions, "No ultimate purpose to life," "Progress is an illusion," and "God
could not exist." (I should admit that I haven't read his arguments of why I
should accept them, but since for each universe compatible with our
observations and experiences, I can imagine a periodic quantum universe that
gives precisely the same observations and experiences, I can't see how the
purpose, progress, and createdness would be any different for the periodic
universe. I wish I could have tried this rebuttal on Nietzsche before he went
into the insane asylum.)
Sixth, I agree with Glenn when he says, "Without something, it is
difficult to see how nothing could become something, i.e. the vacuum.
Philosphically it is more satisfying to say that God must have existed to
create the vacuum. Without a vacuum you can't have the Big Bang. If all you
have is nothing, then you have no vacuum." (The only part here I would
hesitate with is saying that the quantum state of the universe is "a vacuum,"
but to quantum theorists "a vacuum" often just means some state with nice
symmetry properties, not the nontechnical meaning of the word, so I can't
exclude the possibility of using this word here.)
Seventh, I'm glad that Glenn "tend[s] to agree with [my] suggestion
that `in the beginning...' may apply to God's thought processes [and] describes
the planning of the universe, not the execution or actualization of the
universe." I'm afraid I disagree with Eduardo's suggestion of an "absolute
beginning of time." However, some of the verses he cites (e.g., Matt. 19:4,
and Ps. 102:25 and Hebr. 1:10 if "earth" means our planet rather than the
entire universe) might be referring to our common notion of time (probably
approximate) within the present fairly classical epoch of the universe, though
in John 1:1, 2 Tim. 1:9, and Titus 1:2 (and in Ps. 102:25 and Hebr. 1:10 if
"earth" there does mean the entire universe) I would interpret the concept of
time as being more metaphorical, having to do with causation by God rather than
with sequence in physical time, which in any case almost certainly does not
exist even in any approximate sense `before' the creation of the universe, as
Augustine recognized long ago in his Confessions.
Don Page