Special Relativity On Past, Present And Future — Through Systemic Functional Linguistics [2]

Davies & Gribbin (1992: 76-8):

To understand why this is so, you must first appreciate that your now and my now are not necessarily the same. This is because, as we have seen, the simultaneity of two spatially separated events is entirely relative. What one observer regards as happening at 'the same moment' but at another place, a second observer, located elsewhere, may regard as happening before, or after, that moment. … An event on a distant galaxy which we judge to be simultaneous with noon today in a laboratory on Earth can be shifted by centuries, from your point of view, if you happen to change your reference frame by boarding a train.

These ideas have a profound implication. If the 'present moment' elsewhere in the Universe depends on how you are moving, a whole span of 'presents' must exist, some of which will lie on what you regard as your past, some in your future, as seen by different observers. In other words, moments of time cannot be things which 'happen' everywhere at once, in which only the unique present is 'real'. Rather, time is extended in some way, like space; which particular event any given observer regards as happening in the mysterious moment of 'now' is purely relative.

So does the future, in some sense, already exist 'out there'? Might we be able to foresee events in our own future by changing our state of motion? … But it turns out that you cannot travel fast enough to see into your own future.

Blogger Comments:

From the perspective of Systemic Functional Linguistic Theory, the 'present moment' is the time of construing experience as meaning. Because light takes time to travel, observers who see an event in a distant galaxy see, in their present, events that happened in their past — congruently expressed as 'past in present' tense ('has happened'). What varies for different observers moving at different velocities is the duration between the observation and the event in the distant galaxy.

To be clear, moments of time are not things that 'happen'. Time is the dimension along which processes unfold, and it is in this sense that time is 'extended'. Processes are not observable until they unfold.