The
Place of Logic in Philosophy.
The sciences fall into two broad
divisions, viz.: the speculative and the regulative (or normative) sciences.
In the speculative sciences, philosophic thought deals with those things
which we find proposed to our intelligence in the universe: such sciences
have no other immediate end than the contemplation of the truth. Thus we
study Mathematics, not primarily with a view to commercial success, but
that we may know. In the normative sciences, on the other hand, the philosopher
pursues knowledge with a view to the realization of some practical end.
"The object of philosophy," says St. Thomas of Aquin, "is order. This order
may be such as we find already existing; but it may be such as we seek
to bring into being ourselves."¹ Thus sciences exist, which have as
their object the realization of order in the acts both of our will and
of our intellect. The science which deals with the due ordering of the
acts of the will, is Ethics, that which deals with order in the acts of
the intellect is Logic.
¹St. Thomas in Ethic.
I.
lect. 1. Sapientis est ordinare. . . .
Ordo
autem quadrupliciter ad rationem comparatur. Est enim quidam ordoquem
ratio non facit sed solum considerat, sicut est ordo rerum naturalium.
Alius autem est ordo quem ratio considerando facit in proprio
actu, puta cum ordinat conceptus suos ad invicem et signa conceptuum quae
sunt voces significativae. Tertius autem est ordo quem ratio
considerando facit in operationibus voluntatis. Quartus autem est
ordo quem ratio considerando facit in exterioribus rebus, quarum
ipsa est causa, sicut in arca et domo.
The question has often been raised,
whether Logic is science or an art. The answer to this will depend entirely
on the precise meaning which we give to the word 'art.' The medieval philosophers
regarded the notion of an art as signifying a body of rules by which man
directs his actions to the performance of some work.2 Hence
they held Logic to be the art of reasoning, as well as the science of the
reasoning process. Perhaps a more satisfactory terminology is that at present
in vogue, according to which the term 'art,' is reserved to mean a body
of precepts for the production of some external result, and hence is not
applicable to the normative sciences.
Aesthetics, the science which deals
with beauty and proportion in the objects of the external senses, is now
reckoned with Ethics and Logic, as a normative science. By the medieval
writers it was treated theoretically rather than practically, and was reckoned
part of Metaphysics.
It may be well to indicate briefly
the distinction between Logic and two other sciences, to which it bears
some affinity.
Logic and Metaphysics. The
term Metaphysics sometimes stands for philosophy in general sometimes
with a more restricted meaning it stands for that part of philosophy known
as Ontology. In this latter sense
Metaphysics deals not with
thoughts, as does Logic, but with things, not with the conceptual
order but with the real order. It investigates the meaning of certain
notions which all the special sciences presuppose, such as Substance,
Accident, Cause, Effect, Action.
It deals with principles which the
special sciences do not prove, but on which they rest, such as e.g., Every
event must have a cause. Hence it is called the science of Being,
since its object is not limited to some special sphere, but embraces all
that is, whether material or spiritual.
Logic on the other hand deals with
the conceptual order, with thoughts. Its conclusions do not relate to things,
but to the way in which the mind represents things.
²St. Thomas us An.
Post. I., lect. x. "Nihil enim aliud ars esse videtur,
quam certa ordinatio rationis qua
per determinata media ad debitum finem
actus humani perveniunt."
Logic and Psychology. The object
of Psychology is the human soul and all its activities. It investigates
the nature and operations of intellect, will, imagination, sense. Thus
its object is far wider than that of Logic, which is concerned with the
intellect alone. And even in regard to the intellect, the two sciences
consider it under different aspects. Psychology considers thought merely
as an act of the soul. Thus if we take a judgment, such as e.g., "The three
angles of a triangle are together equal to two right angles," Psychology
considers it, merely in so far as it is a form of mental activity. Logic
on the other hand, examines the way in which this mental act expresses
the objective truth with which it deals; and if necessary, asks whether
it follows legitimately from the grounds on which it is based. Moreover,
Logic, as a regulative science, seeks to prescribe rules as to how we ought
to think. With this Psychology has nothing to do: it only asks, "What as
a matter of fact is the nature of the mind's activity?"
The Scope of Logic. Logicians
are frequently divided into three classes, according as they hold that
the science is concerned (1) with names only, (2) with the form of thought
alone, (3) with thought as representative of reality.
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The first of these views — that Logic
is concerned with names only — has found but few defenders. It is however
taught by the French philosopher Condillac (1715 — 1780), who held that
the process of reasoning consists solely in verbal transformations. The
meaning of the conclusion is, he thought, ever identical with that of the
original proposition.
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The theory that Logic deals only with
the forms of thought, irrespective of their relation to reality, was taught
among others by Hamilton (1788 —1856) and Mansel (1820 —1871). Both
of these held that Logic is no way concerned with the truth of our thoughts,
but only with their consistency.In this sense Hamilton says: "Logic is
conversant with the form of thought, to the exclusion of the matter" (Lectures.
I.
p. xi). By these logicians a distinction is drawn between 'formal truth,'
i.e., self-consistency and 'material truth,' i.e., conformity with the
object and it is said that Logic deals with formal truth alone. On this
view Mill well observes: "the notion of the true and false will force its
way even into Formal Logic. We may abstract from actual truth, but the
validity of reasoning is always a question of conditional truth — whether
one proposition must be true if the others are true, or whether one proposition
can be true if others are true" (Exam. of Hamilton, p. 399).
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According to the third theory, Logic
deals with thought as the means by which we attain truth. Mill, whom we
have just quoted, may stand as a representative of this view. "Logic,"
he says, "is the theory of valid 'thought, not of thinking, but of correct
thinking" (Exam. of Hamilton, p. 388).
To which class of logicians should
Aristotle and his Scholastic followers be assigned? Many modern writers
rank them in the second of these groups, and term them Formal Logicians.
It will soon appear on what a misconception this opinion rests, and how
completely the view taken of Logic by the Scholastics differs from that
of the Formal Logicians. In their eyes, the aim of the science was most
assuredly not to secure self-consistency, but theoretically to know how
the mind represents its object, and practically to arrive at truth.
The terms Nominalist, Conceptualist,
and Realist Logicians are now frequently employed to denote these
three classes. This terminology is singularly unfortunate: for the names,
Nominalist, Conceptualist and Realist, have for centuries been employed
to distinguish three famous schools of philosophy, divided from each other
on a question which has nothing to do with the scope of Logic. In this
class we shall as far as possible avoid using the terms in their novel
meaning.
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