**C**: If this sentence (

**C**) is true, then Santa Claus exists. Consider the following argument, where (1) is an obviously true premise:

(1) IfOr, to spell it out,Cis true, thenIfCis true, then Santa Claus exists.

(1') IfNote that the parenthetical antecedent is true whenifis true, then (ifCis true, then Santa Claus existsCis true, then Santa Claus exists).

**C**is true (after all, that's what

**C**

*means*), so (1) pretty clearly entails by modus ponens,

(2) IfBut since the italic claim in (2) above just isifis true, then Santa Claus exists.Cis true, then Santa Claus exists

**C**, (2) is pretty clearly also equivalent to

**C**. So let's sub it in:

(3) If(3), of course, is equivalent toCis true, then Santa Claus exists.

**C**. So it follows from modus ponens on (3) and (3),

(4) Santa Claus exists.Of course, you should feel free to sub in your favorite implausible claim for "Santa Claus exists". This argument would be equally effective at proving that God exists, or that the St. Louis Rams are worthy of praise. There's a lot of big logic-y words in my explanation, but it's actually all very intuitive... if talk of modus ponens and equivalence and entailment makes your eyes glaze over, then just look at the numbered sentences -- you should be able to see that they follow logically from one another. UPDATE 11/21: I had no idea that "Santa Claus" didn't have an "e" in it. How very, very strange.

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