Tom (all)
Sorry to chime in with my apparently simplistic comments, but, yet again, if people started from what the generic form of physical existence (ie that which is potentially knowable to us, and not what we can dream up), then this philosophical debate would never have occurred, ie:
-physical existence is limited (ie a closed system) because it must have detectability (either actual or hypothetically verified on the basis of that), as this is the only form of existence we can be aware of. We cannot externalise ourselves from it, except with belief, as we are part of it. Hence without proper pre-conditions and due process, as we can only ever comparing awareness with other awareness, it is easy to conflate knowledge and belief.
-there is no relativity in physical existence, which is an existential sequence. The entirety of whatever comprises it can only exist within that sequence in one definitive physically existent state at a time. And the predecessor must cease to exist so that the successor can exist, there is no physically existent 'future'.
-there is no time (or more precisely, change) in any physically existent state, this concerns the measurement of the rate at which change occurs between physically existent states
-all physics is local, a physically existent state can only be a physical cause in certain specific conditions in respect of spatial position and sequence order, as physical influence cannot 'jump' physical circumstances
-any form of sensing (ie receipt of physical input by virtue of being in the line of travel and interacting therewith) is independent of physical existence, both in terms of what was physically received and what caused that
-similarly measurement, which is the subsequent comparison of what is identified as existent against a conceptual constant, ie an abstraction of any given manifest feature
-what is sensed is a physically existent representation (in the context of the recipient sensory system) of what physically occurred. There is a timing delay between physical existence and receipt of that representation.
Paul