I just ran across this old thread and it looks like I left you hanging. Sorry. I'll reply now in case you find it again or for others who may be reading this...
>"For all we know, probabilities have no place in any part of quantum mechanics other than in a measurement.
>"Connecting measurement to consciousness is okay, maybe."
That's true, probabilities may only be related to measurement. But measurement is only differentiated from other QM interactions in that it 1) connects the phenomenon to our consciousness, and 2) it connects the QM interaction to the macro, which itself may be what introduces the probabilities (or may not), or it may simply be the change in reference frame.
>"I was referring to the Lorentzian signature of spacetime (the temporal component of the metric has an opposite sign to the spatial components of the metric).This is just math for "time only goes forward", kind of. So the preservation of causality is baked into relativity."
>"This is just math for "time only goes forward", kind of. So the preservation of causality is baked into relativity. "
There are conditions under which those signs change. In a black hole at the Schwarzschild radius time is 0, and beyond that threshold the signs for space and time flip (for some models).
Also, for massless particles, time is 0 in their reference frames, and I believe there can be no causality without time. So, for example, gluons would be non-causal during their existence.
