The universe is the total of that which exists — not merely the earth or the stars or the galaxies, but everything. Obviously then there can be no such thing as the “cause” of the universe . . .
Is the universe then unlimited in size? No. Everything which exists is finite, including the universe. What then, you ask, is outside the universe, if it is finite? This question is invalid. The phrase “outside the universe” has no referent. The universe is everything. “Outside the universe” stands for “that which is where everything isn’t.” There is no such place. There isn’t even nothing “out there”: there is no “out there.”
To grasp the axiom that existence exists, means to grasp the fact that nature, i.e., the universe as a whole, cannot be created or annihilated, that it cannot come into or go out of existence. Whether its basic constituent elements are atoms, or subatomic particles, or some yet undiscovered forms of energy, it is not ruled by a consciousness or by will or by chance, but by the Law of Identity. All the countless forms, motions, combinations and dissolutions of elements within the universe — from a floating speck of dust to the formation of a galaxy to the emergence of life — are caused and determined by the identities of the elements involved. Nature is the metaphysically given — i.e., the nature of nature is outside the power of any volition.