To put it simply: paradox is that in a contradictory problem, neither party can be established (or both parties can not be established), that is, they are caught in a dilemma in their choice.

For example: 1, God is omnipotent. Can he make a stone that he can't move? You can choose, he can't move the stone, he is obviously not omnipotent, you can't choose, he is not omnipotent.

2. A robber tried to kill someone. The robber said,' Do you think I will kill you? I'll let you go if I guess right, and I'll kill you if I guess wrong. "The man said,' You will kill me.' The robber was in a dilemma. If you kill him, it means that he guessed right and should not be killed; If you don't kill him, it means he is wrong, but you should kill him. The robber had no choice but to let him go.