Consider these situation.
Grandfather paradox
You travel back to the past and kill your grandfather. So now, your father won’t be born and neither will you.
So if you are not even born, who killed your grandfather?
Hitler paradox
You travel back to the past and kill Hitler. So history changes and now, there is no Hitler.
Now, if Hitler doesn’t exist, why would you travel back in the first place to kill him?
Infinite loop paradox
A man travel backs to the past and marries a woman. After that, he returns to the present. But the woman gets pregnant and has a son. Many years later, that son becomes the time traveller who goes to the past and marries the woman.
So who is the son and who is the father?
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