Right, spacetime a real concept, just like unicorn is. The fact that it's extremely useful separates it from the concept of a unicorn, which is not so useful. However, this just places it more like the concept of Santa Clause, or the perfect circle, a very useful concept. — Metaphysician Undercover
No it doesn't it just gives us the means for modelling the effects of gravity. General relativity gives us no understanding of gravity itself, none at all. If it did, it could point us to the graviton. — Metaphysician Undercover
I've talked to many physicists, and your claims, that space-time is more than just a conceptual tool, is just not consistent with what these physicists tell me. You're just taking an extremely speculative metaphysical proposition, and claiming that physicists believe this proposition. Maybe some do. — Metaphysician Undercover
In the Wheeler-DeWitt model (for example) time is absent, because the universe as a whole is at rest. This is because the universal wavefunction is in an eigenstate of its Hamiltonian. This in turn is necessitated because otherwise physical quantities would depend on the unphysical c-number parameter t. — Inis
Like I suspected but could be mistaken, change is essential for the concept of time. So, the universe at rest isn't changing and ergo, no time. — TheMadFool
What of this wavefunction? I guess it's a theoretical wavefunction and having no physical counterpart, fails to provide the tick-tock of a clock. — TheMadFool
Infinite divisibility is a red herring. Continuous motion through space-time is the fundamental reality. — aletheist
False, spacetime is real as in it's part of the model of physical reality as understood by both QM and Relativity. — MindForged
Whether or not a graviton exists isn't even understood. — MindForged
(just a feature of space in the presence of matter) — MindForged
Infinite divisibility is an insufficient criterion for continuity. After all, the rational numbers are infinitely divisible--thus serving as the basis for Zeno's paradoxes--but no one takes them to be truly continuous. I now find magnification to be a more perspicuous illustration--no matter how much we were to "zoom in" on continuous space-time, we would only ever "see" continuous space-time--never discrete point-instants.What does "continuous motion" mean other than that the intervals of time and distances are infinitely divisible? — Metaphysician Undercover
No, space-time itself is the terrain, and mathematical models of it are the map. The latter can be incorrect precisely because they purport to represent something real--that which is as it is regardless of what any individual mind or finite group of minds thinks about it.Are you familiar with the analogy of the map and the terrain? Spacetime is part of the map. — Metaphysician Undercover
Infinite divisibility is an insufficient criterion for continuity. After all, the rational numbers are infinitely divisible--thus serving as the basis for Zeno's paradoxes--but no one takes them to be truly continuous. I now find magnification to be a more perspicuous illustration--no matter how much we were to "zoom in" on continuous space-time, we would only ever "see" continuous space-time--never discrete point-instants. — aletheist
No, space-time itself is the terrain, and mathematical models of it are the map. — aletheist
The real is that which is as it is regardless of what any individual mind or finite group of minds thinks about it. The actual (or existent) is that which reacts with other like things in the environment. Hence reality and actuality are not coextensive--besides real actualities (e.g., individual events), there are also real possibilities (e.g., qualities) and real conditional necessities (e.g., laws of nature) that cannot be reduced to collections of their actual instantiations. — aletheist
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