What? It's actually Wednesday? Well, that vagrant lied to me. And I gave him what I bet was a tasty sandwich just to know what day it is.

Lies are funny things, really. They have so many uses. Take the objective morality out of lying, and it becomes a tool unlike any other. Put the objective morality back in, however, and you begin to notice that there's a funny and peculiar thing about some of life's so-called "staple" beliefs that we all take, perhaps erroneously, for granted.

Let's take the old and tired situation about two guards and two doors.

As the classic situation goes, one door leads to life and one to death, and one guard always tells the truth and one always lies.

Some people may recognize this situation from the movie Labyrinth. But I won't talk any about that now.

So here's the part where things start to get dicey.

We can only ask one guard one question to find out which door to choose. The classic answer to this riddle is to ask one of the guards which door the other guard would say is the correct door, revealing the other door as the one that should be chosen.

The classic answer is wrong.

You see, in order for any of this situation to make any sense at all, you have to realize something else first.

BOTH guards always lie.

But how? The agreed upon rule for the situation is that one always tells the truth and one always lies.

Oh really?

And who is supposed to have told you this rule? The guards?

And there's the problem.

Do you see it?

The riddle is based on the rule that both guards agree upon. This can never happen.

In the case of the guard who always lies, agreeing to the rule would be telling the truth because he is agreeing to an absolute truth about the rules of the situation.

In the case of the guard who always tells the truth, agreeing to the rule would be telling a lie because he is agreeing to say that the guard who always lies is, in this one instance, telling the truth about the rule.

They are each a liar.

Big L, small i, small a, small r, period.

Okay, Dave, but who cares?

Well, I just got to thinking about other instances in real life where two sides of something implore you to believe that one of them always tells the truth and one of them always lies.

But maybe these things only make sense on a Tuesday.