Full Idea
Frege should be criticised for using the term 'sense' in two senses. For he takes the sense of a designator to be its meaning; and he also takes it to be the way its reference is determined.
Gist of Idea
Frege uses 'sense' to mean both a designator's meaning, and the way its reference is determined
Source
comment on Gottlob Frege (On Sense and Reference [1892]) by Saul A. Kripke - Naming and Necessity lectures Lecture 1
Book Reference
Kripke,Saul: 'Naming and Necessity' [Blackwell 1980], p.59
A Reaction
This criticism doesn't surprise me, as heroic pioneers like Frege seem to have been extremely unclear about what they were claiming. Kripke has helped, but we still need some great mind to step in and sort out the mess.