Ekstatic Unity
ELI5
Instead of sticking together like glue, the moments of time for a conscious person hold together by each reaching outward toward the others — past, present, and future are united not by collapsing into one thing but by each standing outside itself toward the rest, like links in a chain that only forms a chain by being open at every link.
Definition
Ekstatic Unity is Sartre's term for the distinctive mode of temporal synthesis proper to the For-itself — a unity that cannot be modeled on the self-identical coherence of the In-itself but must instead be grasped as a cohesion that holds together precisely by holding its moments apart. Because the For-itself is never coincident with itself, its temporal dimensions (past, present, future) cannot be fused into a single, compact, substantial whole. Rather, each moment "is outside itself" — the For-itself is always already ahead of or behind itself, standing in an ex-static (literally "standing outside") relation to each of its own temporal phases. The unity in question is thus not achieved in spite of this dispersal but through it: the moments cohere as phases of a single being-toward precisely because they are each stretched outside themselves in the direction of the others.
This concept directly expresses the claim that temporality is the intra-structure of the For-itself's mode of being rather than a container or external framework imposed upon it. Sartre calls the For-itself's being "diasporatic" — scattered across a quasi-multiplicity of moments — and ekstatic unity names the peculiar internal articulation of that diaspora. It is the principle that grounds all intra-mundane multiplicities (including number) without itself being numerical: the For-itself's temporal self-dispersal is original, not derivable from non-temporal elements, and any derivative unity we encounter in the world (spatial multiplicity, series, number) is possible only because the For-itself already holds itself together in this radically non-substantial, ekstatic way.
Place in the corpus
Ekstatic Unity appears once in the corpus, in jean-paul-sartre-hazel-barnes-being-and-nothingness-an-essay-on-phenomenological (p.134), at a pivotal moment in Sartre's account of temporality. It functions as a specification of the For-itself concept: if the For-itself is defined by its structural non-coincidence with itself — being "what it is not and not what it is" — then ekstatic unity is precisely what makes that non-coincidence cohere as a single life rather than simply disintegrating. The concept thus extends and names what is only implicitly present in the bare description of the For-itself, giving the temporal dimension of that non-coincidence its own positive ontological character.
Its relation to the other cross-referenced concepts is equally constitutive. Facticity (the unchosen, inert "that I am") is what the For-itself discovers at the past-pole of its ekstatic spread; Consciousness is the very nihilating movement that prevents this factical pole from collapsing the whole into In-itself-style self-identity; and Negation is the structural motor that keeps each moment "outside itself" rather than folding back into self-coincidence. Ekstatic unity is therefore the synthesis of all these moments: it is how a being constituted by Negation, saddled with Facticity, and incapable of in-itself closure nonetheless achieves a form of unity adequate to its diasporatic existence. In this sense the concept functions as an extension — a positive ontological description — of what would otherwise appear as mere formal features of consciousness's temporal structure.
Key formulations
Being and Nothingness: An Essay on Phenomenological Ontology (p.134)
it will be necessary to constitute a unity of a new type—namely, ekstatic unity in which each state will be outside itself, down there in order to be before or after the other.
The phrase "outside itself, down there" is theoretically loaded because it forces a spatial-directional language onto what is an ontological claim: "outside itself" names the constitutive ex-stasis of temporal being (non-self-coincidence), while "down there" anchors this outside-ness to a concrete, embodied directedness rather than an abstract logical negation — capturing precisely that temporality, for Sartre, is not a formal structure imposed on the For-itself but is lived, situated, and directional from within its diasporatic mode of being.