The expression "to write something down" suggests a descent of thought to the fingers whose movements immediately falsify it.

Gass is skeptical of the common metaphor that writing simply “records” preexisting thought. The phrase “to write something down” implies a clean transfer from mind to page, but he argues that the very act of inscription—choosing words, syntax, emphasis, and sequence—inevitably alters what was first imagined. Thought “descends” into the body (the fingers), and in becoming language it is reshaped, simplified, or distorted. The remark reflects Gass’s broader preoccupation with the materiality of language and the gap between consciousness and expression: writing is not transcription but transformation, and fidelity to an inner idea is always compromised by the medium that makes it communicable.