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

THE PROBLEMS WHICH WE HAVE RAISED. 349
of the general system of things to which A belongs,
and of A s relations to other things in that system.
Only on the basis of a knowledge of elementary geom
etry could we say that any section of a cone by a plane
must be either a circle, or an ellipse, or a parabola, or a
hyperbola, or two intersecting straight lines, or a single
straight line. Examples from mathematics might easily
be multiplied ; for this branch of science is sufficiently
developed for us to make exhaustive disjunctions in
the form "A must be B or C or D, &c." What the
student should grasp, by reflecting upon typical con
crete examples of such judgments, is this : although
the disjunctive form leaves partly indeterminate the
particular reference which is predicated, so that on
this side it may be used to express ignorance, yet,
when it is correctly used, it implicitly refers an in
dividual (A) to a system, and implies at the same time
knowledge of the general nature of the system and of
the individual s place in it. If, in ordinary conversa
tion, the disjunctive form is used to express mere
ignorance and nothing more, it is incorrectly used ;
for it means, "I do not know whether A is B or C
or something quite different." l
The disjunctive judgment is regarded by modem
logicians as expressing the real aim of Thought more
fully than the previous forms :
for it implies the exist
ence of a systematically connected world. And in all
real thinking we are seeking to connect facts together
by means of general principles into a system. To un
derstand this is to grasp the main clue to the solution
of some of the most vexed questions of Logic.
1 The significance of the main forms of Judgment is concisely
reviewed, from the standpoint of Modern Logic, in the author s
Philosophical Criticism and Construction^ chapter iii.