Precis: the truth about writing

Derrida's essay he talks about writing vs myth. He quotes, "The truth of writing, that is, as we shall see, (the) nontruth, cannot be discovered in ourselves by ourselves. And it is not the object of a science only of a history that is recited, a fable that is repeated"(74). Additionally he says the definition of writing is to repeat without knowing (75).
Basically I found his essay to be just pretty much completely playing on contradictions. This is shown most apparently when he discusses Pharmakon. Is it a poison or is it a cure. This question then stems from him questioning of Socrates attitude towards writing, for writing "is not in itself a shameful, indecent, infamous activity" however, "one is dishonored only if one writes in a dishonerable mannor" (68).