This article records tradition as it has been passed down and reported. Its sources are not yet part of the atlas's verified catalogue.
For most of the 1940s, Maurice Merleau-Ponty and Jean-Paul Sartre were read, not unreasonably, as allies in the same philosophical and political project, co-editors of Les Temps modernes and the two most visible faces of French existential phenomenology. By 1955 that alliance had broken apart in public, in print, and the document of the break, Merleau-Ponty's Adventures of the Dialectic, accused Sartre of what he called ultrabolshevism, an unconditional endorsement of revolutionary communism that Merleau-Ponty considered a betrayal of dialectical thinking rather than an expression of it. The charge was political on its face, aimed at Sartre's support for Communist Party discipline and his account of the proletariat's historical role, but the disagreement beneath it was philosophical, and it reached all the way back into the two men's earliest and most technical work on freedom and perception.
Sartre's Being and Nothingness had built its ontology on a stark division between being and nothingness, between the brute, self-identical thereness of things and the consciousness that, precisely because it is nothing in itself, is absolutely free, able at every moment to negate any given situation and choose otherwise. Merleau-Ponty's objection, developed across the Phenomenology of Perception and sharpened in the later political writings, was that this picture of freedom is too clean to describe an embodied life. A person is not a pure nothingness standing outside a world of pure things, choosing from nowhere. A person has a body, and the body has a schema, a set of habitual orientations toward tasks and situations that Merleau-Ponty describes as a kind of situational spatiality, oriented toward what needs doing rather than toward the world as a set of neutral objects. That embodied orientation sediments over time into skills, habits, and institutions that are neither brute facts a free consciousness simply negates nor impositions from outside that erase freedom altogether. They are, on Merleau-Ponty's account, exactly the middle ground that Sartre's dualism of being and nothingness has no room for, and it is that missing middle ground, he argues in the Adventures of the Dialectic, that makes genuine history and genuine political praxis impossible on Sartrean terms, because a freedom that is absolute at every instant cannot accumulate into anything, cannot learn from a situation, cannot be gradually formed by a tradition the way real political actors are.
This is why the quarrel that looked, from the outside, like a falling out over how to relate to the French Communist Party was in fact the political expression of a disagreement that had been present since Merleau-Ponty's earliest account of the body as being toward the world, a pre-objective orientation that precedes and conditions any act of deliberate choice. If freedom is, as Sartre held, a standing power of consciousness to negate whatever is given, then revolutionary action can in principle remake a situation entirely from the outside, uncommitted to what came before. If freedom is instead always already embodied, already sedimented into a body's habits and a society's institutions, in the way Merleau-Ponty's account of perception insists, then political action has to work with and through what history has already deposited in people, rather than against it.
The friendship did not survive the disagreement, and the two men were effectively estranged for the rest of Merleau-Ponty's life. What their split leaves behind is a genuinely open question that later phenomenology, including feminist critiques of Merleau-Ponty's own late ontology of flesh, has continued to press from other directions: whether a philosophy of embodiment of the kind Merleau-Ponty offers can secure freedom at all, or whether, once perception and habit are given the constitutive role he assigns them, freedom risks dissolving into the very sedimented structures it was supposed to explain.