Forgive me if I rant a wee bit, here:
- If you know a lot about the subject (more than those around you) then speak up confidently and share what you know.
- If you know a little about the subject (less than those around you) then ask constructive questions—share what you don’t know.
- If you know nothing about the subject, then shut up and listen—eventually you’ll come to understand at least a little.
- If no one in the conversation knows what they’re talking about—change the subject.
Notice that in none of these cases do you have any reason to hesitate, self-deprecate, or apologize for speaking up. Certainly, you should distinguish opinions from factual claims, and express reservations or qualifications some of the time. But whenever I hear a fake apology: I’m not a scientist, but… or I don’t know that much about economics, but obviously… I’m going to assume you’re in case 2 or 3, pretending to be in case 1.
Short version: if you have to apologize for what you’re about to say, don’t say it.