ZapperZ said:
If you were to ask this in, say, the physics forums, here's how I would have tackled this based on what we know now:
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These are not "philosophical" issues because these are physical issues that one CAN test based on a starting premise. Rather than argue about something based on a matter of TASTES (a discussion that normally solves nothing and goes nowhere), wouldn't it be more productive to actually set out a series of tests to evaluate the VALIDITY of such a statement?
Zz -- thanks for the very relevant response... despite my starting this thread in the wrong forum! You suggest that -- treating this as a physics question -- we should be able to do an experiment that gives us an answer.
The thing is, any conceivable experiment we perform -- tracking the motion of an electron in a vacuum, for example -- will involve making space and time measurements using atomic matter. If that's so, it's maybe impossible to test whether the spacetime structure we observe depends on the existence of atomic matter. That would makes it a useless question from the standpoint of normal, everyday physics.
The reason I think the question might not be useless is this. Our current theories tell us that atoms first came into being something like 300,000 years after the universe began. Those theories also explain a lot about the universe, on the assumption that the structure of space and time and the laws of physics were well-defined and essentially the same as they are today, going back all the way to the first microseconds. So there is a lot of evidence that says, spacetime structure has nothing to do with atoms!
Yet, Quantum Mechanics gives us a general prescription that at the fundamental level, if something isn't measured, it should be described as a superposition of all its possible states. So it might make sense to imagine that before there were atoms, space and time (and physical laws) should be described as a superposition of all possible configurations, and that the emergence of atoms amounted to a cosmic "measurement event" in which one configuration was selected that was capable of defining / measuring itself.
Since we ourselves exist within that configuration, and gather all our data using atomic matter (and the laws of physics that support it), perhaps it makes sense that we can now construct a consistent history of our universe going back long before there were atoms... as if those same principles were always valid.
But in QM, you can verify the existence of superpositions by showing interference between alternate possibilities. If there's no possibility of doing that with respect to different pre-atomic configurations of our universe, this again may not be a testable hypothesis.
Even so, it might turn out to be a way of explaining why the complicated structure of the laws of physics is the way it is. It seems to open up the possibility of a functional analysis, where we could say -- we have to have several different fundamental stuctures, like the electromagnetic field and the gravitational field, because we can only measure and define anyone of them in terms of the others. The laws of physics need to be "finely-tuned" to support the existence of stable, steadily oscillating structures like atoms, because those structures are needed to measure space and time, etc.
Physics already gives us specific dependencies between matter and gravitation, electric charge and the e/m field, etc. But we don't have an explanatory approach that can meaningfully ask, why we have these very different kinds of structure, and why they work so well together to support all the diverse phenomena in our universe. So asking about what it takes to measure (physically define) space and time is groping toward an approach that might eventually make those questions meaningful for physics.
