Full Idea
The mechanisms that deliver falsehoods are somehow parasitic on the ones that deliver truths.
Gist of Idea
Whatever in the mind delivers falsehood is parasitic on what delivers truth
Source
Jerry A. Fodor (Psychosemantics [1987], p.107)
Book Reference
Fodor,Jerry A.: 'Psychosemantics' [MIT 1993], p.107
A Reaction
In the case of a sentence and its negation it is not clear which one is 'parasitic', because that can usually be reversed by paraphrasing. Historically, I very much hope that truth-speaking came first.