DOCTOR: Excuse me. What's your attitude towards the nature of existence? For example, do you hold any strong theological opinions?

GUARD: I think you'll find most educated people regard mythical convictions as fundamentally animistic.

DOCTOR: I see. That's a very interesting concept.

GUARD: Personally, I find most experiences border on the existential.

DOCTOR: Well, how do you reconcile that with the empirical critical belief that experience is at the root of all phenomena?

GUARD: I think you'll find that a concept can be philosophically valid even if theologically meaningless.

DOCTOR: So, what you're saying is that before Plato existed, someone had to have the idea of Plato.