Is Popeye talking about the simple fact of his existence when he says I yam whad I yam, or is he talking about the manner of his existence?
If Popeye was referring to the simple fact of his existence why does he not simply say – I am [or I yam] why does he have to add the supplementary what I yam – what does the additional: what I am add to his statement and how does it change the import completely?
The what is not the true interrogative in this case, but a relative determinant which has the meaning I am that which I am. It is Popeye’s rum-fueled assertion about the modality, class, kind, or nature of his existence. But he uses it without furnishing us with any predicative life-style details. They remain covert like God's mountaintop I am response with Moses. We are expected to know about the way that Popeye exists a priori. Of course millions of children all over the world DO know in advance about Popeye’s manner of behaviour and his liking for spinach, and his love for the skinny-ribbed Olive, and his fights with the huge, towering rival for Olives three-fingered hand.
When God said to Moses, Tell them the great I am sent you, he expected Moses and the Children of Israel who were cavorting around the Golden Calf at the foot of the mountain down below to fill in the the great one's predicational information for themselves.
Examples of predicational pruning are often produced by sundry transcendentalists anxious to disprove the rejection of the so-called verb /be/ as an instantiator of pure, un-essenced, un-propertied simple existence.