Rand held her axiom Existence exists to include that the universe as a whole “cannot be created or annihilated, that it cannot come into or go out of existence” (1973, 25). One would naturally suppose Rand was thinking that immunity from creation or annihilation means the universe has existed an endless time in the past and will exist an endless time in the future. Plausible as that picture appears, might the axiom Existence exists not strictly entail the endless duration of Existence? Might it entail only that at no time was there nothing at all or that at no time was there no time, yet not also entail that the duration of the existence of Existence extends into a past that is infinite? Might the boundary of the past be finite, and at the first, the universe have its present mass-energy (as in classical GR back to the Initial Singularity) and be passing time, yet since it was the first of time, there be no “before” that first, and it simply not be sensible to talk of a “becoming” from a “before” the first?
In our philosophical reflection, should we prejudge the physics of whether the universe of mass-energy and its spacetime extend into an infinite or only a finite past? Should that issue be left to scientific cosmology to settle? Nearby issues such as whether time, space, or spacetime in any way have causal powers and whether there are more primitive physical elements from which spacetime arises should not be prejudged by philosophy, I say. Rather, thoseissues should be left open for scientific cosmology to settle. I think, however, that philosophy can and should go beyond observing that there was no time and will be no time at which there was nothing, go on to the conclusion that Existence is eternal, meaning endless in past and future.
If no Existence at all, then no character-identity at all. Had Existence come into existence, it would have to do so in a specific way, yet that way would be some character-identity, which requires some existents and is an existent, and by hypothesis there were no existents. Coming to be without a way, as Parmenides realized, is nothing. Moreover: Coming to be is itself an existent. Coming to be of the all that is Existence would be coming to be of any coming-to-be at all. That cannot be sensible unless there were some background existence lacking any coming-to-be. But by hypothesis there was no existent of any sort—thence no existent lacking coming-to-be—before the coming into existence of Existence. Therefore, Existence has no beginning. Then too, absent power of coming-to-be of its entire self, Existence cannot come to be not. That is, Existence has no end.
Rand did not accept the idea that the universe as a whole is in time. She thought that time was one of those things applying to things within the universe but not on up to the entire universe itself. One might sensibly say, in Rand’s view: Existence, the entirety of all existents, is eternal in the sense that it is outside of time, but not in the sense that it exists endlessly. That is erroneous. As my life advanced in time, so did the Milky Way advance in time, Andromeda too and on up to the whole universe. That is how our modern physics has it also. The universe has a certain age since such-and-such event, most importantly, since the event of the Initial Singularity (or Planck-scale of the spacetime around that classically projected event). Existence as a whole endures through definite time, and that is not to say that time or alteration can exist without other sorts of existents.
 Cf. Aristotle, Cael. 279b4–84b5; Broadie 2009; Sorabji 1983, 205–9, 245–49.
 Cf. Lennox 1985, 68.
 “What coming to be of it will you seek? / In what way, whence, did [it] grow? Neither from what-is-not shall I allow / You to say or think; for it is not to be said or thought / That [it] is not. And what need could have impelled it to grow / Later or sooner, if it began from nothing?” Gallop 1984, Fragment 8, lines 6–10.
 Matter is mass-energy having nonzero rest mass. Only matter and its changes can be a clock. Were the universe to contain no matter, only pure energy, there would be nothing registering the advance of time. So far as I know from modern physics, time would yet advance while a pure-, all-energy of the universe and its changes (say, internal propagations at vacuum light speed) existed. A universe purely energy, of course, would be an existent.
The current picture from scientific cosmology is that the quantity of mass-energy in the universe today is the same there has been all the way back to the Initial Singularity. Particles of ordinary matter, the neutrinos (they have nonzero rest mass), emerged after the first ten-thousandths of a second following the onset of expansion of the universe from the Initial Singularity. Dark matter, having rest mass, may have been present before the neutrinos. I gather that at the present state of scientific knowledge the remote future (years from now about 10 to the 100th power, whereas the present day is only about 10 to the 9th power from the Initial Singularity) of our ever-expanding universe will contain only or very nearly only massless particles such as photons and gravitons (Penrose 2011, 139–49).
 Branden 1962; c. 1968, 82–83, 101–2; Rand 1990 App. 273; Binswanger 2014, 26. Cf. Peikoff 1991, 16; Gotthelf 2000, 48.
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