[Serious] Is the Past Real?

[Anomalocaris]

It could be a small substellar mass primordial black hole slung shot towards us due to a close encounter with a pair of closely orbiting massive objects, so that it is too small to be accreting noticeable amount of matter from interstellar medium, and traveling too fast for it have been in the vicinity of the solar system for long enough to create detectable gravitational perturbations.

We can outline the known constrains on each element of this scenario, and in principle arrive at a probability of its occurance.   although because the constraints on some element, like the number of sub stellar black holes, are very loose, the range of probability is also going to be wide.

But this is an example of unknown, but in principle knowable.

Exactly. It has a truth value that *could* be determined.

Now, for quantum events, that is not the case.

So, suppose that I pick a single uranium atom. ALL we have is probabilities for when it will decay. We do NOT have, even in principle, a way to determine when it will decay. So the statement that it will decay tomorrow at noon is neither true nor false.

But I can go further. Suppose I have isolated a uranium atom last week. I have neither looked at it nor had any detector consider it. Is the statement that it decayed two days ago at noon one that has a truth value?

I would say not, just as the statement that it will decay tomorrow at noon does not.

I think we need to separate what is in principle unknowable to us, as opposed to what is in principle not knowable at all, when we say whether the past is real.    It seems to me If it is in principle knowable to someone somewhere, then it is real.   It is just that we don’t know it and can’t know it.  Chaucer’s last meal is in principle knowable to someone, even if we hypothesize that some quantum event forever obscures it from us and anyone with whom we in principle can communicate. 

It seems to be that the principle of indestructibility of information says all past must be knowable to someone somewhere, so it is real.