Différance is ontologically prior to presence and absence and so unknowable

Evidence

The play constitutive of signification thus necessarily involves both the disruption of presence, which is always part of a chain of substitutions which transcend it, and the reference to presence, but a presence which can never fully be achieved but is constantly deferred. Différance is thus ‘the obliterated origin of absence and presence’. Différance can only be conceptualized by means of a language which necessarily, by virtue of the nature of différance itself, involves the metaphysics of presence: différance, since it is ontologically prior to both presence and absence, is therefore unknowable. From this contradiction springs the practice of deconstruction which involves contesting the metaphysics of presence on its own terrain - a terrain from which there is any case no escape. — Alex Callinicos, Against Postmodernism, 310

Categorization

• DEFINE: Defines différance and derives deconstruction — the contesting must occur on a terrain there is no escape from, which is precisely the double-bind structure of strategic essentialism.
• QUESTION: If there is ‘in any case no escape’ from the metaphysics of presence, this directly parallels whether strategic essentialism can escape residence-in essence — a key stop in the reader’s research.