Today I spent quite a bit of time tracking down a software bug. The bug was puzzling because as far as I could see it was completely impossible — there was no way it could exist — yet there it was.
Then at some point I realized that if what I was looking at was impossible, then I must be looking in the wrong place. So I started looking in completely different places, and eventually I found the true culprit — and promptly fixed the bug.
I realized at that point that Sherlock Holmes had figured all of this out a long time ago. He said, and I quote “When you have eliminated the impossible, whatever remains, however improbable, must be the truth.”
I am pretty sure he was talking about debugging computer programs — or something very much like it.