An introductory text-book of logic - Mellone, Sydney - Rare Books at ...

THE PREDICABLES. l6p
the colouring of certain animals is shown to be pro
tective under Natural Selection. A simpler instance is
"
the fact that Man is capable of desiring knowledge,"
which is one of the general propria of humanity result
ing from the specific property of
"
rational thought."
Of course various properties may follow from a concept,
which are not peculiar to the species in question. If par
allelograms are conceived as four-sided rectilineal figures
with opposite sides parallel, it follows that their opposite
sides are equal ; but this is true of many figures which are
not parallelograms. Again, the characteristic of water, the
power of transmitting pressure equally in all directions,
follows from the physical concept of water, but is true of all
fluids.
(c] crvfi^e/SrjKO^, accident}
This rendering of the term is not satisfactory. It
signifies the concept of a state or condition which does
not necessarily belong to the thing. The fact that it is
unessential may be recognised in two ways :
it may be
long to some members of the class and not to others,
"
This clover has four
"
leaves
to an
; or it may belong
individual at one time and not at another, "The sun
is eclipsed," or, "Socrates is standing in the Agora."
The first of Aristotle s Predicables,
"
Definition," is
of such importance as to require special treatment (see
4 to 6).
3. The account of the Predicables which we have
given differs in some important respects from the
traditional account. The latter was not derived directly
from Aristotle, but from an Introduction to Aristotle s
Categories, written by Porphyry, who taught Logic in
Rome about six centuries after Aristotle s time. This
Introduction became accessible to the mediaeval logi
cians in a Latin translation made by Boethius about two
centuries after it was first written.