Full Idea
Mill seemed to defend the view that proper names are merely labels for individual persons or objects, and contribute no more than those individuals themselves to the meanings of sentences in which they occur.
Gist of Idea
Proper names are just labels for persons or objects, and the meaning is the object
Source
report of John Stuart Mill (System of Logic [1843]) by William Lycan - Philosophy of Language
Book Reference
Lycan,William G.: 'Philosophy of Language' [Routledge 2000], p.37
A Reaction
Identity statements can become trivial on this view ('Twain is Clemens'). Modern views have become more sympathetic to Mill, since externalism places meanings outside the head of the speaker.