The Instant

In Sartre's ontology of the for-itself, "the instant" names a specific mode of temporal rupture that arises when the subject undergoes a radical conversion — a total restructuring of its original project. Because the for-itself is constitutively temporal (it ekstases simultaneously toward past, present, and future in a unified field), there is ordinarily no discrete "now" in the sense of a self-enclosed atomic moment: temporality is always already stretched across its three dimensions. The instant becomes thinkable only at the limit, precisely where one project ends and another begins, where the subject is simultaneously its own end and its own beginning within a single act. At this juncture, the ekstatic unity of temporal flow is interrupted; the for-itself cannot be continuous with what it was, nor can it be continuous with what it will be — it must, in a single movement, negate the whole field of meaning it had constituted and institute a new one.

This rupture is grounded in the ontological identity of freedom, nihilation, temporalization, and choice that Sartre establishes throughout Being and Nothingness. Because the for-itself is "what it is not and is not what it is" — perpetually distanced from itself by the nothingness it secretes — any moment of radical conversion does not merely alter a decision but reshuffles the entire field of the possible and the meaningful. Anguish is the affect that discloses this possibility: it reveals that no past project can bind the for-itself with the necessity of the in-itself, that a rupture is always possible. The instant, accordingly, is not a phenomenological datum among others but a structural marker of the for-itself's absolute freedom — both its unjustifiability and its fragility, since any "absolute" choice remains perpetually exposed to the nihilating power of a future conversion.

The concept of the instant appears in jean-paul-sartre-hazel-barnes-being-and-nothingness-an-essay-on-phenomenological (p. 466) as part of Sartre's account of radical conversion and the structure of freedom. Within that text's argument, it functions as the limiting case of ekstatic temporality — the point at which the ordinary synthesis of past, present, and future breaks down under the pressure of the for-itself's absolute freedom. It is therefore an extension and specification of Sartre's broader account of consciousness (cross-referenced here as a canonical concept): whereas consciousness for Sartre is always a nihilating transparency constitutively distanced from itself, the instant names the extreme form this nihilation takes when it disrupts temporal continuity altogether rather than merely sustaining the ordinary flow of existence.

The instant also resonates structurally with several of the Lacanian canonicals cross-referenced here, though it operates in a distinct ontological idiom. The closest parallel is with Anxiety: just as anxiety in Lacan marks the terrifying proximity of what would close the gap of desire, anguish in Sartre is the affect that discloses the perpetual possibility of the instant — both are structural signals rather than contingent feelings, and both hover at a threshold where subjective continuity is endangered. The instant equally intersects with Negation: the radical conversion that produces the instant is precisely an act of absolute internal negation — the for-itself negates its own prior project, an operation structurally analogous to what the corpus, following Hegel and Freud, describes as the productive, world-constituting power of negativity. Finally, the instant touches on Lack insofar as the rupture it enacts exposes the want-of-being (manque-à-être) at the core of the for-itself: that no project can fill the void, that the subject's being is perpetually in deficit, is exactly what the possibility of a radical conversion — and thus of the instant — keeps making visible.

Being and Nothingness: An Essay on Phenomenological OntologyJean-Paul Sartre · 1943 (p.466)

The instant will be then both a beginning and an end... It will exist therefore only if we are a beginning and an end to ourselves within the unity of a single act.

The phrase "a beginning and an end to ourselves within the unity of a single act" is theoretically loaded because it collapses the two poles of temporal ekstasis — origin and termination — into a single, self-coinciding gesture, making the instant irreducibly self-referential: the subject is not merely the agent of the rupture but its content, the one who both concludes and inaugurates itself. The words "unity of a single act" are crucial: they signal that this is not a sequence (first ending, then beginning) but an ontological simultaneity, which is precisely what makes the instant a genuine rupture in ekstatic time rather than just a change of mind.