Redshirts John Scalzi Let me start by asking you a question. Is Spock (science officer of the Enterprise, played by Leonard Nimoy in the original Star Trek) real? Here's the answer given by a Cornell philosophy professor (probably Max Black ) Whenever anyone asked him whether something was real, he always gave the same answer. The answer was "Yes." The tooth fairy is real, the laws of physics are real, the rules of baseball are real, and the rocks in the fields are real. But they are real in different ways. -- Max Black (?), quoted in Sokal's Hoax, by Steven Weinberg So, yes. If you buy Black 's ontology, Spock is real. Hermione Granger is real, ghosts are real, money is real, the Presidency of the USA is real, SO(3), the group of three-dimensional rotations -- all of them are real. They are real, even though they exist only in people's minds. Now, I admit that if someone asks me with no context, "Are ghosts real?", I will answer "No....