Another way to look at it: from an objective, scientific perspective - the perspective we would ordinarily seek to determine or state any truths about the world - the concept of "now" has no meaning.

There is a dimension of time with a series of values etc but none of those values has any particular privelege over any other.

So the concept of "now" is entirely subjective - it exists only in our minds (well in mine actually).

It follows that past and future are equally meaningless, objectively.