Laure, you write (#19), concerning questions of cosmic infinity:
But ultimately, does it matter?
You have a kindred spirit in Ayn Rand. In her Anthem, she gives her protagonist the following deliverance:
I know not if this earth on which I stand is the core of the universe or if it is but a speck of dust lost in eternity. I know not and I care not. For I know what happiness is possible to me on earth. (1946, p. 87)
Contrary to popular saying, the Copernican revolution has no valid implication that diminishes the importance of human life. The discovery that the sun does not orbit the earth does not change human importance. Physical size, mass, or centrality are not the scales of value. The phenomenon of life—life right here on earth—is the source and perpetual support for all value, meaning, and significance.
Like the minds posting here, and the human mind for thousands of years past, Rand wondered what is out there in the cosmos. In that sense of care, she cared. In her developed philosophy, she took her most basic axiom, existence exists, to imply “that nature, i.e., the universe as a whole, cannot be created or annihilated, that it cannot come into or go out of existence” (MvMM 25)
It is often said that the universe came into existence at the big bang (the initial singularity). That is inaccurate. The theory and observations that tell us there was a big bang also tell us that the mass-energy of the universe has been constant all along the way, even back at the beginning of time (its boundary in the past). Extended space and time may have come into existence at the big bang, but a nonzero finite amount of mass-energy was never absent.
I think that Rand was correct in saying that we know the universe did not come into existence and that we know this prior to our discoveries in contemporary cosmology grounded in physics. But it is a delicate matter, for I would not want to rule out a beginning of time or space simply from the armchair.
General relativity led us to knowledge of the big bang. The big bang does not represent an explosion of matter into preexisting space. There was no preexisting nonsingular space; there was no spatial distance, area, or volume; there was only that single point of spacetime. In addition,
since spacetime structure is itself singular at the big bang, it does not make sense, either physically or mathematically, to ask about the state of the universe “before” the big bang; there is no natural way to extend the spacetime manifold and metric [past-ward] beyond the big bang singularity. (Wald 1984, 99)
We should not, however, expect classical general relativity (which is what Professor Wald is writing about here) to apply all the way back to an absolute singularity. To fathom the very beginning, we need a quantum theory of gravity.
On the question of the beginning of time or of space, I will wait for physics.
(Edited by Stephen Boydstun on 8/18, 10:40am)