Time doesn't actually exist - discuss

I don't understand arguments that suggest time isn't real.

Also, I'm a naiive realist but have no way to prove this.

Well Kero, there's a theory that everything in the past and future is still happening, it's just that our perception forces us to see the past as fixed and immutable and the future as nebulous. However, this may not be how the world actually works.

I read the words and they make sense. I just don't 'get' how its possible if that makes any sense.

We'll we've sort of proven it to some extent by relativity. If you leave one clock on earth and put another one in a super fast jet, time ticks slower for the one on the jet.

Tbh, I don't think we're meant to understand it, otherwise we'd experience every moment of our lives simultaneously which would be incomprehensible.

I don't see any obvious connection between the theory of relativity and what you suggest.

The theory of relativity postulates that space and time are relative, which necessarily means that there cannot be objective and discrete portions of time (i.e. past, present, future).

For example, when we look at stars we're actually seeing past events occurring. Therefore, in a sense that past is still occurring. Similarly, another civilisation may be viewing our planet and observing it how it was in medieval times. So which time period are we actually in then, 21st century or middle ages? That's basically what I'm getting at.

The theory of relativity postulates that space and time are relative, which necessarily means that there cannot be objective and discrete portions of time (i.e. past, present, future).

For example, when we look at stars we're actually seeing past events occurring. Therefore, in a sense that past is still occurring. Similarly, another civilisation may be viewing our planet and observing it how it was in medieval times. So which time period are we actually in then, 21st century or middle ages? That's basically what I'm getting at.

Although, in order for time to be a relative property of space-time, it must exist.

In a sense, but it just seems to be some sort of field, not discrete portions like past and future which is what most people mean when they say time.

Do you think so? Past and future are compatible with relativity, since they are relative concepts. For example, if I am in your super fast jet, my clock from your perspective will be running slower than yours. And vice versa, from my perspective your clock is running slower than mine. We don't have to say that there is an objective perspective from which one of these is more correct than the other - my past and future are just different to your past and future.

I agree, they exist from a relative perspective, which is where I think the question "does time exist" breaks down as it is too vague. However, I presume most people take it to mean if past, present and future exist as objective states regardless of perspective or ultimate reality.

Yeah, I suppose it really depends what we're actually talking about. There can be an objective chronology perhaps, since we can use neutral frames of reference, but whether that's enough to say the past and future exist depends what we mean when we use the words past and future. If we want something where all frames of reference agree, then of course that's not going to happen.

Although, in order for time to be a relative property of space-time, it must exist.

Except if there is only one entity in the universe for which no change occurs, say a point of infinite density at the beginning of the universe?

Is space relative?

Yes, it changes relativistically. See Lorentz contraction, where space shrinks depending on your frame of reference.

Of course I remember now, I only really think of time dilation in relativity. Can you just explain who the contraction occurs for? I'm guessing based on time dilation that the observer will see space contract in front of him so distances become shorter to him than to an observer at near light speed?

Okay so we can take three frames of reference for comparison. There is a person standing at point A, another at point B and a third at point C, equidistant from each other. The person at point B travels at a speed close to the speed of light towards the person standing at point A. From person B's perspective, the space between himself and the person at point A shrinks. Likewise, the person at point A sees the space between himself and the person travelling from point B also shrink. This is because in relativity, person A cannot tell whether he is moving towards person B or if person B is moving towards person A. Therefore from both of their perspectives, Lorentz contraction occurs and the space between them appears to shrink.

Person C, being equidistant to points A and B, has a neutral frame of reference. Person C sees person B travelling at close to the speed of light towards person A. From person C's perspective, the space between person B and person A does not shrink. The shrinking occurs only in the direction of things moving towards one's own frame of reference.

Time dilation is connected to this, and as a result of space-time warping according to the differing frames of reference, events seen as occuring simultaneously by person A, B or C will not be guaranteed to be seen as occurring simultaneously by the others. This leads to the phenomenon known as the relativity of simultaneity.

Hope that makes sense.

Yes that makes sense thank you for explaining . However if C is in line with B then from C's perspective then B is moving away from C at the speed of light or C is moving away from B at the speed of light so surely then the distance between B and C actually also appears to increase? I'm not sure if ''appears'' is the right word because distance actually does increase?

Do you study physics then?