Nothing

Beckett to Duthuit:

The expression that there is nothing to express, nothing with which to express, nothing from which to express, no power to express, no desire to express, together with the obligation to express.

Blanchot:

The writer finds himself in the increasingly ludicrous condition of having nothing to write, of having no means with which to write it, and of being constrained by the utter necessity of always writing it.

Quoted by Steve at In Writing.