How does the passage of Time?
The past exists because it happened, the present exists for not even a brief moment, and the future regularly becomes a moment of present. What a terrible glutton the past is yes?
But perhaps this is a good thing; I want to think the past is a point of ordered definition that can be reflected and looked upon; and I mean that in quite a literal sense; you can't change it, but you can look at it by messing with enough electricity, and mirrors to see when the past was a present and be able to do nothing to stop what you are seeing.
Imagine that, looking through Time's Telescope, at the great catastrophes, seeing the events unfold before your very eyes as if they were your current present, but there's nothing you can do, because they already happened, and you just watch them happen, now with full knowledge.
You can't do this for the future, because the future isn't ordered quite yet, it's actually a field of potential possibilities that in the brief moment of present transforms from unordered possibility to defined ordered past.
To look upon the past really only requires one telescope, to gaze upon the future, well, you'd need infinite telescopes, and even then, it wouldn't be enough.
Past -->Present--Future;
Infinite Unordered Potential--> Transformer --> Singular Ordered Dataset
You can look at the singular because it's ordered, you can literally punch a little window in time to see it as it were. That violates no principals. Just good luck with getting the right angling and having the perfect viewing time.