Sorry about the message above^^ It's my first time posting here!
What I think that subject means is that most of the time, great discoveries in science aren't in any way, shape or form premeditated. They just happen, by pure chance (hence "that's funny"). As an example, you could cite the discovery of penicillin in the mid '40s (you could do a little research on that, you'll find plenty of stuff in any encyclopedia).
Hope that helps!