Deductive Logic | Page 6

set of impressions produced in it

by one object from those which are produced in it by others. Thus,
when Vergil says
Incipe, parve puer, risu cognoscere matrem,
he is exhorting the beatific infant to the exercise of the faculty of
comparison.
§ 44. That a common term implies comparison does not need to be
insisted upon. It is because things resemble each other in certain of
their attributes that we call them by a common name, and this
resemblance could not be ascertained except by comparison, at some
time and by some one. Thus a common term, or concept, is the
compressed result of an indefinite number of comparisons, which lie
wrapped up in it like so many fossils, witnessing to prior ages of
thought.
§ 45. In the next product of thought, namely, the proposition, we have
the result of a single act of comparison between two terms; and this is
why the proposition is called the unit of thought, as being the simplest
and most direct result of comparison.
§ 46. In the third product of thought, namely, the inference, we have a
comparison of propositions either directly or by means of a third. This
will be explained later on. For the present we return to the first product
of thought.
§ 47. The nature of singular terms has not given rise to much dispute;
but the nature of common terms has been the great battle-ground of
logicians. What corresponds to a singular term is easy to determine, for
the thing of which it is a name is there to point to: but the meaning of a
common term, like 'man' or 'horse,' is not so obvious as people are apt
to think on first hearing of the question.
§ 48. A common term or class-name was known to mediæval logicians
under the title of a Universal; and it was on the question 'What is a
Universal 7' that they split into the three schools of Realists,
Nominalists, and Conceptualists. Here are the answers of the three

schools to this question in their most exaggerated form--
§ 49. Universals, said the Realists, are substances having an
independent existence in nature.
§ 50. Universals, said the Nominalists, are a mere matter of words, the
members of what we call a class having nothing in common but the
name.
§ 51. Universals, said the Conceptualists, exist in the mind alone, They
are the conceptions under which the mind regards external objects.
§ 52. The origin of pure Realism is due to Plato and his doctrine of
'ideas'; for Idealism, in this sense, is not opposed to Realism, but
identical with it. Plato seems to have imagined that, as there was a
really existing thing corresponding to a singular term, such as Socrates,
so there must be a really existing thing corresponding to the common
term 'man.' But when once the existence of these general objects is
admitted, they swamp all other existences. For individual men are
fleeting and transitory--subject to growth, decay and death--whereas the
idea of man is imperishable and eternal. It is only by partaking in the
nature of these ideas that individual objects exist at all.
§ 53. Pure Nominalism was the swing of the pendulum of thought to
the very opposite extreme; while Conceptualism was an attempt to hit
the happy mean between the two.
§ 54. Roughly it may be said that the Realists sought for the answer to
the question 'What is a Universal?' in the matter of thought, the
Conceptualists in the form, and the Nominalists in the expression.
§ 55. A full answer to the question 'What is a Universal?' will bring in
something of the three views above given, while avoiding the
exaggeration of each. A Universal is a number of things that are called
by the same name; but they would not be called by the same name
unless they fell under the same conception in the mind; nor would they
fall under the same conception in the mind unless there actually existed
similar attributes in the several members of a class, causing us to regard

them under the same conception and to give them the same name.
Universals therefore do exist in nature, and not merely in the mind of
man: but their existence is dependent upon individual objects, instead
of individual objects depending for their existence upon them. Aristotle
saw this very clearly, and marked the distinction between the objects
corresponding to the singular and to the common term by calling the
former Primary and the latter Secondary Existences. Rosinante and
Excalibur are primary, but 'horse' and 'sword' secondary existences.
§ 56. We have seen that the three products of thought are each one
stage in advance of the other, the inference being built upon the
proposition, as the proposition