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

176
DEFINITION.
An obviously circular definition may
be an epigram :
thus,
be intended to
"
an archdeacon is one who exer
cises archidiaconal functions," would have point in the
case of a faineant archdeacon. But implicitly this
fault is constantly committed :
"
Justice is giving to
each man his due" In long and involved scientific dis
cussions, it is very easy to formulate two or three sep
arate definitions which, when taken together, are seen
to be merely circular. The same fault may
be com
mitted by
" A cause
using the correlative of the
is that which produces an
term defined :
Mere
effect."
repetition of a word does not vitiate a definition ; we
may define
"
contrary opposition
which, &c.," having already defined
being now concerned to define
"
"
as
"
"
opposition in
"
opposition
contrariety."
and
(5) The definition should not be negative where it
can be positive ; and, as a special instance, opposites or
contraries should not be defined by one another.
"
(6) To these rules may be added, what is often a
counsel of perfection," that the definition should con
tain nothing superfluous.
Thus, Euclid s definition of a square contains more
than is necessary ; for it is shown (Euc., i. 46) that if a
figure has four equal sides, and one of its angles a right
angle, the other three angles must also be "
Again, when Mill : says A cause is
right angles.
the assemblage
of phenomena, which occurring, some other phenom
enon invariably commences, or has its
origin," we may
express all this (with the additional advantage of drop
ping the ambiguous term
"
phenomenon ") in the
simple statement :
" The cause of an event is that which
occurring, the event occurs."
6. The distinction of
"
"
nominal or
"
"
verbal and
"
"
real definitions was first given by Aristotle. He