Ultimate truth

[MonkeyFire]

But memories fade.

Remembering is futile, but memory will remain.

 

[Martin]

Remembering is futile, but memory will remain.

Not when you have dementia.

 

[dybmh]

But memories fade.

Yes. Sometimes. But it's not predictable. Sometimes many many years can pass, and a song or a familiar smell ( baking bread or cookies, perfume or cologne ) can make an old memory fresh "just like it was yesterday".

Sometimes it doesn't even need that.
"Absence makes the heart grow fonder"?

 

[Firemorphic]

[You make valid points,] assuming time itself is linear and not cyclic or random,

Time is three things, even though they seem to contradict each other: 1, Cyclical. 2, Relative. 3, False.

or that everything that we perceive is illusory to begin with.

Yep, we see things the same as you in this regard. Dunya = Maya and Samsara (somewhat).

 

[Firemorphic]

In the case of alternate realities the past still doesn't change. Each alternate reality has its own permanent past.

Logically there are about 6 or so overlapping aspects to this but all possible realities are in some regards part of infinity, all that can be, is 1 and 0 but we cannot be foolish enough to think that time exists in any linear fashion even though we perceive it as such. All pasts, presents and futures are one "Now".