tautology.

Did you know that there is philosophy in Popeye?

Yes that Popeye with the stick thin girlfriend called Olive.

Popeye always says "I yam what I yam, and that's all what I yam" right?

In philosophy, this saying is in accordance with the Law of Identity which states that whatever is, is. Google it if you wanna know more. It took me sometime to read through and understand but it is quite interesting.

Also read about

Law of Noncontradiction: Nothing can both be and not be

and

Law of Excluded Middle: Everything must either be or not be

if you found the Law of Identity interesting cause these three laws are known as the classic Laws of Thought by Aristotle.