When would you presume something rather than assume it?

Answer 1

They are both the formation of belief-statements. I would say that presume is in some ways more presumptuous that assume and in other ways less (i.e. a presumption is a special kind of assumption that may, often temporarily only, disregard the facts. A presumption may be modified by facts, however, as legal presumptions are, for instance, but an assumption is generally made for the purpose of deliberately abstracting from reality for the purpose of an argument and therefore is not permitted, within the terms of the argument, to be modified).

Answer 2

We presume something rather than assume it when the facts or circumstances surrounding it are still in a state of doubt and we suppose it to be true and take it for granted, unlike "assuming" when we have already accepted it as true before there is proof.

Answer 3

They are really synonyms of each other, but in usage presume can take on an air of arrogance, like a know it all who doesn't really verify the truth, where assume is basically accepting something without verifying if it is true.

Answer 4

You presume by words spoken and you assume by actions.