My original training was as a scientist, even if I'm an engineer now. I learned a long time ago, to separate what is known, from what is unknown. It's an important distinction that a lot of people don't think to locate accurately. . .
Your background is similar to mine in that respect. Rumsfeld said something about knowing what we know, knowing what we don't know, not knowing that we don't know. I check my yard for space aliens every day, but so far nothing. Some day though, who knows.