[andrewas]

If he's telling the truth, then he's lying because hes telling the truth and saying he's lying, and this sentence makes no sense because it can make no sense. I need a drink.

However, if he is lying, then not everything he tells you is a lie. Unlike the previous supposition, this dosent go into a circular nightmare. Depending on how you interpret the riddle, anyway.

So he's lying, because if he's telling the truth he cant be telling the truth.

My head hurts now.