> So what good does it do me what the objective truth is?

I don't disagree that true propositions that aren't known to me, aren't useful to me.

I just don't draw the conclusion that "true" and "possible to know" is the same concept. Maybe that depends on what possible means. Like "theoretically possible" vs "practically possible".

> There might in fact be an objective Truth [...] assuming the objective Truth is the red ball is there [...]

This looks to me like you agree that unknowable truths can exist.

You say there are propositions that can be true without anyone knowing them as it happens to be, such as a particular person is a philosophical zombie - a biological robot, or there being water on a planet beyond the observable universe.

You say that there are no true propositions without anyone knowing them because they are impossible to know, by principle, such as undetectable ghosts existing or them not existing.

Is that correct? That would be less controversial than if propositions of the first category couldn't be true either. I'm not sure, maybe the philosophical zombie belongs in the second category. Consciousness is weird anyway.

Can you think of good examples that people really care about in the second category - principally unknowable, and therefore impossible to be true or false claims?

Supernatural claims often just propose alternative physics. People say that ghosts act against the laws of physics, but they could theoretically exists and if they turned out to exists, the written laws of physics would need to be adjusted to accomodate them.

The existance of the judeochristian god is a weird claim. It depends how he is actually defined. Maybe god according to an unfalsifiable definition would occupy this space of neither true or false.

Is god's existance an example of unknowable claim? Does it make the claim neither true nor false or just false?

You can ignore the rest if you don't have much time.

"Possible" is an interesting word. I have a theory that possibility as opposed to certainty always has something to do with incomplete knowledge. In a universe without conscious humans with blind spots, there is no "possibility". It's not an inherent property of a shuffled deck of cards to be random. It can just be random to an observer. That's my weird theory.

If I'm correct then there is no difference between a fact that is impossible to know and a fact that I just happen not to know. Everything that is not actually the case, is impossible and everything that is the case, is impossible to be different. Possibility only arises when you don't know some facts or ignore them.

Well, maybe there are levels of impossibility. I can get to late to work, because I didn't set an alarm. Given that fact, it is impossible to arrive on time - but this excuse won't impress my boss. If I had to break the laws of physics or even logic, that's an arguably deeper level of impossibility.