[philosopher1234]

I think irrational is something like retaining a false belief despite it being clear that it is false. It’s got something to do with holding on to a point of view despite its inadequacy.

[cybernautique]

Then much of science is irrational; what about those times where it's understood that a belief is false, but it also holds the most explanative power of all other considered beliefs?

And, again, the notion that something is 'clearly false' at some point presupposes perfect information about the context within which the belief is held.