 The distinction between the intension (or connotation) and extension (or denotation) of names, which traces back to the  Port Royal Logic,  was widely acknowledged by nineteenth century logicians. But the distinction was applied, as a rule, to general names, not proper names. With regard to proper names, logicians generally sided with John Stuart Mill in holding that they lack connotation. Keynes, for example, writes that proper names are “non-connotative”—that is, “their application is not determined by a conventionally assigned set of attributes” (Keynes 1906, 42).