The point of the chestnut tree is that it is not a chestnut tree. It simply exists, free of ‘essence’, or any assigned meaning. It is at that moment that Antoine is pulled from the past he has immersed himself in (his book), and is fully aware of what the nausea which has been ailing him truly is. It is the sickening awareness and freedom that is caused by his realization that essence is nonexistent. Everything is given unnecessary essence by people who never realized, like Antoine did, that everything simply, and only, exists. Names, descriptions, and attached emotions are fabrications of lesser human minds, all made up to mask the “obscene nakedness” of existence.
Antoine immediately is rendered speechless when he tries to describe the chestnut tree, and is suddenly aware that is so because words do not describe anything real or tangible. Colors, like the purple suspenders, are only words and descriptions manufactured by man to hide an objects true existence. He realizes that his nausea is caused by the fact that he is surrounded and trapped in a world of fake, unreal things like color. This epiphany triggered by the tree suddenly wakes Antoine to the fact that humans attach meaning to give things a purpose for existing. The root is not a root, it is not black, it just is. He is jarred by his abrupt understanding and decides that the idea of something existing for a purpose is ludicrous. He asserts that everything is contingent and fortuitous, and that his existence, along with everything’s, is just a fortunate accident