ence,
the distinction between the predicables, Differentia, Proprium, and
Accidens, is founded, not on the nature of things, but on the
connotation of names. The _specific difference_ is that which must be
added to the connotation of the _genus_ to complete the connotation of
the _species_. A _species_ may have various _differences_, according to
the principle of the particular classification. A _kind_, and not
merely a class, may be founded on any one of these, if there be a host
of properties behind, of which this one is the index, and not the
source. Sometimes a name has a technical as well as an ordinary
connotation (e.g. the name Man, in the Linnaean system, connotes a
certain number of incisor and canine teeth, instead of its usual
connotation of rationality and a certain general form); and then the
word is in fact ambiguous, i.e. two names. _Genus_ and _Differentia_ are
said to be of the essence; that is, the properties signified by them are
connoted by the name denoting the _species_. But both _proprium_ and
_accidens_ are said to be predicated of the species _accidentally_. A
proprium of the species, however, is predicated of the species
necessarily being an attribute, not indeed connoted by the name, but
following from an attribute connoted by it. It follows, either by way of
demonstration as a conclusion from premisses, or by way of causation as
effect from cause; but, in either case, _necessarily_. Inseparable
accidents, on the other hand, are attributes universal, so far as we
know, to the species (e.g. blackness to crows), but not _necessary_;
i.e. neither involved in the meaning of the name of the species, nor
following from attributes which are. Separable accidents do not belong
to all, or if to all, not at all times (e.g. the fact of being born, to
man), and sometimes are not constant even in the same individual (e.g.
to be hot or cold).

CHAPTER VIII.

DEFINITION.

A definition is a proposition declaring either the special or the
ordinary meaning, i.e. in the case of connotative names, the
connotation, of a word. This may be effected by stating directly the
attributes connoted; but it is more usual to predicate of the subject of
definition one name of synonymous, or several which, when combined, are
of equivalent, connotation. So that, a definition of a name being thus
generally the sum total of the essential propositions which could be
framed with that name for subject, is really, as Condi