Full Idea
Mental state (in either the individualistic or the collective sense) does not fix reference.
Gist of Idea
Neither individual nor community mental states fix reference
Source
Hilary Putnam (Reason, Truth and History [1981], Ch.2)
Book Reference
Putnam,Hilary: 'Reason, Truth and History' [CUP 1998], p.25
A Reaction
The idea that communities fix reference seems to me plausible. See Tyler Burge on this.