Materialism

I define matter as the “primary substrate”. It is the cause of all movements, including electricity and chemical reactions, and deeper quantum effects. There simply isn’t anything other than it, as it is capable of causing everything observable, including observation itself.

In opposition to materialism is the belief that there are immaterial things in the universe, such as Mind or God, or to a lesser degree Logic or Ideas. I’ll call this position Idealism.

Is Idealism needed? Can we account for all of everything with matter in movement alone? I think with a strong enough definition of matter, we can. What do you think?

Matter isnt the cause of quantum effects, the time stream, etc. It affects these things to a degree, but spacetime exists independently of matter, that's integral to our whole understanding of the Universe.

Could the universe exist without matter? I'm thinking back to Plato's Timaeus, where he called matter the "Necessary" (the word "matter" is a much later invention).

As we understand the Universe, matter did not exist before the big bang. Physicists ordinarily work separately with quantum mechanics, which rules the microworld of particles, and with general relativity, which applies on large, cosmic scales. But to truly understand the Planck epoch, we need a complete theory of quantum gravity, merging the two.

We still don't have a perfect theory of quantum gravity, but there are attempts – like string theory and loop quantum gravity. In these attempts, ordinary space and time are typically seen as emergent, like the waves on the surface of a deep ocean. What we experience as space and time are the product of quantum processes operating at a deeper, microscopic level – processes that don't make much sense to us as creatures rooted in the macroscopic world.

According to string theory formulations for the beginning of the Universe two branes, enormous membranes much larger than the Universe, collided, creating mass and energy. The first long-lived matter particles of any kind were protons and neutrons, which together make up the atomic nucleus. These came into existence around one ten-thousandth of a second after the Big Bang.

In the Standard Model of particle physics, matter is not a fundamental concept because the elementary constituents of atoms are quantum entities that do not have an inherent "size" or "volume" in any everyday sense of the word. So yes, our Universe existed as a singularity (The thing that would Big Bang) before matter existed within it.

And maybe according to String theory, the fundamental make-up of the universe that you speak of may be hidden in the "bulk" or the hyperspace we can't see as we are only 3-dimensional.