Full Idea
A subject's thought is about A, but, unbeknownst to the subject, B is substituted for A. Then there is Field's 'partial reference', because the subject's thought is still partially about A, even though they are following B.
Gist of Idea
'Partial reference' is when the subject thinks two objects are one object
Source
report of Hartry Field (Theory Change and the Indeterminacy of Reference [1973]) by François Recanati - Mental Files in Flux 2
Book Reference
Recanati,François: 'Mental Files in Flux' [OUP 2016], p.30
A Reaction
Used to interpret a well-known case: Wally says of Udo 'he needs a haircut'; Zach looks at someone else and says 'he sure does'. Recanati explains it by mental files.