Do I contradict myself? Very well then I contradict myself, (I am large, I contain multitudes.)
He is talking about the way he keeps disagreeing with what he says. he says how The condition or quality of being numerous. and what he does shows he doesn't care about what he is contradicting himself.

The spotted hawk swoops by and accuses me, he complains of my gab and my loitering.
He hints in this one at the thought of Nature. He says that the hawk does this becasue of him talking and loitering. and this is imposible for an animel to talk to a person.