[Footnote 2: The history of the definition of the _Proprium_ is an example of the tendency of distinctions to become more minute and at the same time more purposeless. Aristotle's [Greek: idion] was an attribute, such as the laugh of the man or the bark of the dog, common to all of a class and peculiar to the class (_quod convenit omni soli et semper_) yet not comprised in the definition of the class. Porphyry recognised three varieties of [Greek: idia] besides this, four in all, as follows:--(1) an attribute peculiar to a species but not possessed by all, as knowledge of medicine or geometry; (2) possessed by a whole species but not peculiar to it, as being a biped in man; (3) peculiar to a species, and possessed by all at a certain time, as turning grey in old age; (4) Aristotle's "proprium," peculiar and possessed by all, as risibility. The idea of the Proprium as deducible from or consequent on the essence would seem to have originated in the desire to find something common to all Poryphyry's four varieties.] [Footnote 3: It is a plausible contention that in the case of the Singular name the extension is at a minimum and the intension at a maximum, the extension being one individual, and the intension the totality of his attributes. But this is an inexact and confused use of words. A name does not _extend_ beyond the individual except when it is used to signify one or more of his prominent qualities, that is, is used with the function of a general name. The _ex_tension of a Singular name is zero: it has no extension. On the other hand, it suggests, in its function as a Singular name, no properties or qualities; it suggests only a subject; _i.e._, it has no intension. The ambiguity of the term Denotation helps the confusion in the case of Singular names. "Denote" in common speech means to indicate, to distinguish. But when in Logic we say that a general name denotes individuals, we have no thought of indicating or distinguishing: we mean only that it is applicable to any one, without respect of individuals, either in predication or epithetic description.]