The only thing I believe that has no beginning and no end is higher-dimensional space, or "hyperspace" -- a realm that may theoretically exist beyond or in-between universes.
I agree with you on this one e_h. In Stephen Hawking's A Briefer History of Time (the updated version of his initial A Brief History of Time) he writes that if the initial boundary conditions of the universe occur in a singularity where the laws of physics break down, there is no way we can know how it began. Something outside of the universe would have to initiate the beginning. But he counteracts this with his no-boundary theory. This theory states that time has no beginning and no end. The theory is an extension of the development of Richard Feynman's A Sum of Histories and Imaginary Time. A model of the universe which has no beginning and no end. He also mentions God. He writes:"the possibility that space-time was finite but had no boundary, which means that it had no beginning, no moment of creation, has profound implications for the role of God in the affairs of the universe. So long as the universe had a beginning, we could suppose it had a creator. But if the universe is really self-contained, having no boundary or edge, it would have neither beginning nor end, it would simply be. What place, then, for a creator?" A universe without beginning or end, strictly governed by the laws of science and physics.
Hawking writes: "If we do discover a complete theory, it should in time be understandable to everyone, not just a few scientists. Then we shall all, philosophers, scientists, and just ordinary people, be able to take part in the question of why it is that we and the universe exist. If we find the answer to that, it would be the ultimate triumph of human reason---for then we would know the mind of God."
I think because of the simple fact that space-time is expanding, it must be finite and it must have had a beginning. If it had no beginning and no end then it would already encompass everything that exists, and thus would be static.
The laws of our
physics break down at the singularity.
I think most of us believe the universe couldn't have come into existence from absolutely nothing (no space/no energy). Some sort of energy had to exist. And for energy to have existed, it must have had space to exist in. But how could anything at all interact, to create matter, in an infinite three-dimensional
void? Hyperspace is the only theoretical realm where quantum particles (energy) can jump into one another (thus interaction can occur). And hyperspace doesn't expand, since it has always been there, eternally. This is why I believe hyperspace (or higher-dimensional space) has no beginning and no end.
One hint that our univserse is probably embedded in higher-dimensional space is "quantum entanglement" -- quantum particles interacting over astronomical distances instantaneously.
I don't believe what I believe because it's what I desire to believe. I believe what I believe because it's what logic causes me to believe.