Full Idea
If I hear someone say "He has a beard", and I don't know whether it is Jackson, Jones, or someone else, I don't know which proposition is being expressed in the sense of not knowing the conditions under which what is said is true.
Gist of Idea
I can understand "He has a beard", without identifying 'he', and hence the truth conditions
Source
Frank Jackson (From Metaphysics to Ethics [1998], Ch.3)
Book Reference
Jackson,Frank: 'From Metaphysics to Ethics' [OUP 2000], p.73
A Reaction
This is the neatest and simplest problem I have encountered for Davidson's truth-conditions account of meaning. However, we probably just say that we understand the sense but not the reference. The strict-and-literal but not contextual meaning.