Full Idea
If thoughts have their causal roles in virtue of their contents, then two thoughts with identical contents ought to be identical in their causal roles.
Gist of Idea
Do identical thoughts have identical causal roles?
Source
Jerry A. Fodor (Psychosemantics [1987], p.140)
Book Reference
Fodor,Jerry A.: 'Psychosemantics' [MIT 1993], p.140
A Reaction
A pencil would presumably have the same causal role if it wrote a love poem or hate mail. But a pencil is also good for scratching your back. 'Causal role' can be a rather vacuous idea.