zoobyshoe said:
Stop right here, cause you've already stepped outside the bounds of linguistic rigor.
Ah, so
you're in charge here... Yessir!
zoobyshoe said:
Einstein employed time as the 4th dimension in a new way of analysis but this is not a definition of time. Einstein defined time as the movement of clock hands.
I would say, if you're getting into semantics, you're on dodgier ground. To say that Einstein defined time as the movement of clock hands is like saying he defined space as the length of a ruler. What Einstein said was that mechanical clocks
serve for the definition of time. There are two important distinctions here: one is the word 'serve'. He is not saying a mechanical clock
is the definition of time, but that for our purposes it will
act as a definition. The second is the lack of mention of 'moving clock hands', the reason being that it is not the movement that is relevant, but the reading of the clock. For an observer with some given velocity, the reading of the clock gives a numeric co-ordinate, in the same way that the 100 cm mark on a ruler is only 100 cms from the 0 cm mark. So starting from t=0, when the observer checks his clock again and it reads thirty seconds, the time co-ordinate is t=30 (if the unit is seconds). Thus the clock gives you a measure of position in personal time. As I see it, this is no more what time is than the ruler is what space is. As for Einstein's view on time as the 4th dimension, he himself said that it makes no sense to separate the temporal dimension from the spatial ones when determining relations between events. i.e. to relate event A to event B in any objective way you must consider the spatial AND temporal relations between them together. This, in the context of this thread, seemed a more relevant definition of time than personal time.
zoobyshoe said:
"The flow of time" and "time itself" are, really, just turns of speech, also without a rigorous definition. I think the distinction you made between them is idiosynchratic to you.
You think wrong. The two terms are very different. The memory of the past but not the future is an unsolved problem as there is no identifiable reason why this must be so. There is an observed flow of time that is not necessitated by time itself. I think what is happening here is that you have a personal definition of the word 'time' meaning 'the flow of time', which is how everything is used to thinking of time. But time in SR is isotropic. If you accept this, it is difficult to understand how you can not differentiate between the flow of time and time itself. In an interview with Penrose I read, he believed the consensus among physicists to be that the flow of time
is an illusion - i.e. it is totally a consequence of perception. I won't pretend to have any idea as to the consensus on the flow of time among physicists, hence I stated that it
may be an illusion.
zoobyshoe said:
Did Newton actually assert an absolute time the same way he asserted an absolute space? I have been under the impression that the concept of an "absolute time" was just an assumption inherent in all physics and wasn't attributable to any particular individual.
Yes, he defined them together, in fact time first then space immediately after (Principia Mathematica):
"Absolute, true, and mathematical time, of it self and from its own nature, flows equably without relation to anything external, and by another name is called 'duration'; relative, apparent, and common time is some sensible and external (whether accurate or unequable) measure of duration by means of motion, which is commonly used instead of true time, such as an hour, a day, a month, a year."