> There is no source of truth

There is no «source of [_simple_] truth» for complex things, but there are more (instead of less) objective complex evaluations.

Note that this is also valid for factual notions: e.g., "When were the Pyramids built?".

Ancient Egypt chronology is a poor example of determined knowledge.

We do not know in fact exactly when (which?) Pyramids were built, there are large margin of errors in the estimates.

That was my point: answering that question is a more complex evaluation than others. In lower percentiles you may have "what is in front of you" and in upper percentiles you may have "how to fix the balance of power in the Pacific" - all more or less complex evaluations.

I said, "Not even factual notions are trivial, e.g. "When has this event happened" - all have some foundational ground of higher or lower solidity".

Right, I misread your comment. Sorry!