Alright, so I got the individual parts of what Merleau-Ponty is talking about. Descartes' idea of 'I think, therefore I am,' the idea of all non-palpable things being conveyed as essences, and the overall gist being we cannot examine these essences unless we start at the one thing we know, ourselves. There are then a good five pages after he gets through all of that though, and I think I'm missing that entirely.
With that in mind, I really want to tie him to James' Pragmatism. James focused on how 'true' is a property assigned by humans and it has nothing to do with whether things exist. Ponty is trying to decipher what the essences are according to him, therefore assigning them a truth that relates only to him. Also, both share the relational epistomology. "I am the absolute source, my existence does not stem from my antecedents, from my physical and social environment; instead it moves out towards them and sustains them, for I alone bring into being for myself." (page 277) In other words, we decide what we consider/how much we include in our world and it is through our experiences that we know it. He doesn't have to know exactly what they are. "My field of perception us constantly filled with a play of colors, noises and fleeting tactile sensations which I cannot relate precisely to the context of my clearly perceived world, yet which I nevertheless immediately 'place' in the world." (page 278)