 This closure has emerged, says Derrida, with the latest developments in linguistics, the human sciences, mathematics, and cybernetics, where the written mark or signifier is purely technical, that is, a matter of function rather than meaning. Precisely the liberation of function over meaning indicates that the epoch of what Heidegger calls the metaphysics of presence has come to closure, although this closure does not mean its termination.  Just as in the essay “On the Question of Being” (Heidegger 1998, 291-322) Heidegger sees fit to cross out the word “being,” leaving it visible, nevertheless, under the mark, Derrida takes the closure of metaphysics to be its “erasure,” where it does not entirely disappear, but remains inscribed as one side of a difference, and where the mark of deletion is itself a trace of the difference that joins and separates this mark and what it crosses out. Derrida calls this joining and separating of signs différance (Derrida 1974 [1967], 23), a device that can only be read and not heard when différance and différence are pronounced in French. The “a” is a written mark that differentiates independently of the voice, the privileged medium of metaphysics. In this sense, différance as the spacing of difference, as archi-writing, would be the gram of grammatology. However, as Derrida remarks: “There cannot be a science of difference itself in its operation, as it is impossible to have a science of the origin of presence itself, that is to say of a certain non-origin” (Derrida 1974 [1967], 63). Instead, there is only the marking of the trace of difference, that is, deconstruction.