1. A Cretan sails to Greece and says to some Greek men who are standing upon the shore: “All Cretans are liars.” Did he speak the truth, or did he lie?
2. A week later, the Cretan sailed to Greece again and said: “All Cretans are liars and all I say is the truth.” Although the Greeks on the shore weren’t aware of what he had said the first time, they were truly puzzled.

If someone says “I always lie”, are they telling the truth? Or are they lying?