It's not that comparable... a better comparison would be that the top panel protagonist says "Nature exists" and the antagonist says "prove it!"

In this case the protagonist is struck with a problem, if the antagonist is not able to identify nature already, there is nothing distinct that the protagonist can point to which is distinctively nature.

Most assuredly the protagonist can point to the baseball and say "that is part of nature" but he will not be pointing to it and saying "That is nature" or this would create the equivocation that Baseball = Nature and Nature = Baseball.

The protagonist must be able to show the antagonist that nature is a composite of all things which exist in nature. He may try using synonyms like existence, reality or universe. But if the antagonist is unfamiliar with these terms or chooses to be particularly difficult to prove his point, the protagonist must find another way to describe nature, such that its all-encompassing, omnipresent and omnipotent qualities are understood by hearing the word nature.

The protagonist may proffer "Nature is not any particular thing, it is all things. Nature is omnipresent, existing everywhere, it inheres in all things, all things being of nature itself." They may go further, becoming eerily like one who is professing a supernatural deity "Nature is that from which a thing originates, that within which it has its form, and that unto which it terminates. Nature is both beginning and end. Alpha and Omega" (Para. Aristotle, De Animalibus).

All this in an attempt to define what nature is. Which makes this a much closer comparison.

The task of the protagonist would be made exceptionally difficult if the antagonist suffered from my namesake "Simultanagnosia" or the inability to perceive objects as elements of a larger whole. In other words; the inability to see the forest for the trees.