[m4nu3l]

Because you simply can't define "preset" in absolute terms. Two events that happen at the same time in my frame of reference might happen one after the other in your frame of reference.

If the past nor the future exist and you first see one of the things happening, then the other, but I see them happening at the same time I'm seeing things that shouldn't exist in a single moment.

https://en.wikipedia.org/wiki/Relativity_of_simultaneity

[affgrff2]

Okay, want I cannot directly agree with in your original post is the notion that flow of time is an illusion and that it follows from the argument. Obviously, as you argue, with relativity, it is not possible to have an absolute 'now'. But isn't it possible to have a local flow of time? All things you perceive are not the events themselves (happened in your past), but their effects on your now.

[m4nu3l]

> But isn't it possible to have a local flow of time?

You can use a clock to measure time, but I think it's better to say that matter and energy move through time, just like they move through space instead of saying that time flows, because flow implies time which makes the definition circular.

So I would just say that if you consider any frame of reference you can define time with respect to it. But still there is no real "present" in time just like there is no "here" in space. You can just take any point in space and say it's your origin.