Does the fact that water boils at 200 degrees on a mountaintop show that it is an error to say that water boils at 212 at sea level?
I don't think that one's certain conclusions become wrong when new things are learned. I think one differentiates between two contexts that one previously had no reason to differentiate.
Sort of a beta comment
I'm thinking this isn't the right way to add something in the talk section 'cuz I can't see the original comment but working from memory... I'd say that is a good example of the contextual nature of certainty. I was developing this point on HPO when the hypertroll problem persuaded me to just leave, so this never got worked out; but I think a lot of confusion follows from ignoring the fact that truth is a mental recognition of fact, and it isn't a particular sentence that you happen to utter as a way of telling others about that recognition. Anyhow, I think the problem is important enough to deserve a page.
There isn't a clear convention about this in Wiki-land, but I think it's somewhat important if you make a major change in a page that you say something in the talk part that says roughly what you did and why. So for example, what motivates deleting a significant part of the Certainty entry? This is just a suggestion: the point is, I'm inclined to restore the deleted parts, so I'd like to hear what the reasoning is.