Not sure which parent you mean, but if you mean my comment, I wasn't talking about absolute certainty at all. Rather, I was attempting a reductio ad absurdum against theories which talk about the probability of different universes within a multiverse. Nothing I said is an argument against probabilistic reasoning/knowledge limited to the confines of this universe only.

I don't understand your criticism, and I think you might have been mis-understanding my intent. The Everettian (Many Worlds) interpretation of Quantum Mechanics is itself at odds with the concept of absolute certainty. I am thinking about this in terms of E. T. Jaynes perspective that probability theory is an extension of traditional logic, and is required for reasoning about the MWI.

I'll also note that I did miss the point of the OPs comment, but I think not in the way you suggested.