Calvin and Hobbes by Bill Watterson for August 09, 1995
Calvin: We rely on sight to confirm the existence of things. We don't believe in things we can't see. So how do we know that no-see-ums exist? Verification is ruled out by definition! It's an ontological quandary. Hobbes: Hold still a moment. Calvin: Ooh, I itch! Hobbes: Glad I could help.