With all due respect, I'm really skeptical about your claims.

First, we don't "posit" spacetime.

Special and General Relativity were introduced to explain an increasingly large number of observations that were incompatible with Newtonian mechanics, starting with the Michelson-Morley experiment. These theories are predictive, they make a lot of strong, testable claims, and in the century since they were introduced, these claims have been tested over and over again, succeeding every time.

But there is absolutely no hard evidence that consciousness transcends our material world, and people have been trying to examine that claim for literally millennia.

And there's plenty of evidence against this hypothesis. Seeing people whose entire personality is changed by drugs, a brain injury, or dementia is pretty convincing that physical changes, even very minor ones like ingesting a few micrograms of LSD, can make dramatic changes in consciousness.

Even more than that, every single human since the dawn of time has either died, or will die, and in all that time there hasn't been one piece of hard evidence of consciousness surviving the death of the body.

Yes, there are plenty of anecdotes, but consider what it's like to be human: many people, including myself, hate the idea of my consciousness being erased at death and are clearly willing to believe all sorts of facts about the world in order not to believe that. These facts contradict each other almost entirely - it's not just that, say, Muslims disagree with Christians, it's that both of these religions have numerous subgroups that believe mutually contradictory things.

Also, I'm sort of baffled at bringing in Parmenides, though I'm hardly an expert in that area. Surely he was the one of the first people who claimed that all we see of the world is through our senses, and that these are grossly deceptive and lead to a false picture of the world?

And I'd say that his idea that the world is changeless and existence is timeless and uniform has been pretty well refuted by modern science, where the universe has a hard beginning, and goes to a "soft" ending where even though matter continues to exist, nearly all structure has been destroyed.