Full Idea
Atomism must be right about the individuation of concepts because compositionality demands it.
Clarification
'Compositionality' is building up thoughts from components
Gist of Idea
Compositionality requires that concepts be atomic
Source
Jerry A. Fodor (LOT 2 [2008], Ch1)
Book Reference
Fodor,Jerry A.: 'LOT 2: the Language of Thought Revisited' [OUP 2008], p.20
A Reaction
I suppose this seems right, though Fodor's own example of 'pet fish' is interesting. What is supposed to happen when you take a concept like 'pet' and put it with 'fish', given that both components shift their atomic (?) meaning in the process?