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XVI. The
Construction of the Sciences
Topics:
- A. Logic as a teaching method, and as a
branch of philosophy
- B. Judgment
- C. Reasoning
- D. Scientific systematization and its
methods
A. Logic as a teaching
method, and as a branch of
philosophy
Thomas asks whether logic is an art or a
science, and comes to the conclusion that it is
both.
The thirteenth century, in fact, considered
logic as an art and retained the practice of
exercises in logic. At the universities of Paris
and Oxford, students were trained in the analysis
of syllogisms, the refutation of sophisms, and the
discussion of arguments for an against a given
thesis. This kind of logic, which the early Middle
Ages placed among the seven liberal arts under the
name of Dialectica, is not strictly
speaking a branch of philosophy.
But, side by side with this instrumental logic
destined to discipline the mind, as athletic
exercises train the muscles, the philosophers of
the thirteenth century recognize and cultivate a
philosophical logic which consists in a study of
the architecture of human knowledge or of the
methods adopted by the mind in the construction of
the sciences, whether particular or philosophical.
In this meaning of the term, logic itself is a
science. It takes as its subject matter the whole
content of knowledge, in order to study the laws
which govern its coordination, synthesis, and
systematization; and just as knowledge reaches an
objective reality, logic too, in the final analysis
leads us to truth and to certitude. We may say that
in the realm of their logic, the Schoolmen not only
followed but also completed Aristotle.
B.
Judgment
The most elementary construction of knowledge is
the judgment, or the perception that a content of
representation (for instance, 'white') applies or
does not apply to another (for instance, 'snow').
It consists in the union or disunion of the two
contents of representation (II, D).
Science has to do with only one kind judgment,
the necessary and universal judgment, known as a
'law.' Scientia non est de particularibus.
-- Science has nothing to do with particular cases,
or mere 'atomic propositions.' The logical law, or
judgment, may be dependent upon, or independent of
experience. Accordingly, it is included in one of
the two classes of judgments which we have called
above judgments of the existential and of the ideal
order (IV, B).
Let us consider each of these classes in more
detail.
(a)
With judgments of the ideal order, we are
confronted with the process of pure deduction. An
understanding and a comprehension of the subject
and the predicate are sufficient in making the
necessity of their connection evident, -- just as
in order to affirm the principle of contradiction
it is enough to understand the meaning of being and
non-being.
Mathematical judgments are of this sort; and the
only difference between these and the directing
principles of knowledge is that the latter are the
foundation of all affirmation,
whereas mathematical judgments relate only to a
special field, namely quantity.
Moreover, the judgments of ideal order with
which mathematics is concerned belongs to the same
two types which we already discussed in connection
with the directing principles. Thus mathematics
comprehends
- Judgments in which the subject considered in
its essential elements includes the predicate,
as for instance, 2 + 2 = 4.
- Judgments in which the predicate is not
included in the subject, although a comparison
of the content of both is sufficient to make the
necessity of their connection evident. That
every number is either odd or even, remarks
Thomas Aquinas, is a judgment belonging to that
second type. The content of odd or
even is not comprehended in the
notion of number, but from the
mere comparison of both it appears that being
odd or even is a necessary property of every
number.
(b)
With the judgments of the existential order, we are
confronted with the process of induction. A
comprehension of the meaning of chlorine and oxygen
is not sufficient to reveal the law governing their
combination. Observation and experiences are needed
in order to discover how they react to one another;
and the law is obtained by applying to observation
and experience such directing principles as those
of sufficient reason and causality. For, these two
principles justify us in concluding that the
convergence and constancy of observed phenomena (as
for instance the boiling of water under the action
of heat) can only be explained by reference to a
tendency on the part of the substance to act in a
particular way, a tendency which is stable, and
rests upon the nature of the thing in question
(thus it is of the nature of water to
boil at 100 degrees C.). The Schoolmen did not
study the methods of experiment with care and
detail. This was only to be expected, seeing that
the experimental sciences were in an undeveloped
state in those times. But we already find among
them -- notably John Duns Scotus, who flourished a
few years after Thomas -- a keen analysis of the
methods of induction, or the ways by which we may
pass from the observation of
particular cases to the law which
governs all.
C.
Reasoning
A process of reasoning is itself a system of
judgments, since it consists in passing from
judgments already known to another less known or
not known at all. The syllogism, which is the
simplest expression of reasoning, consists of three
judgments. It starts out from the enunciation of a
law, or of a necessary relation, based upon the
nature of things (for instance, "it is of the
nature of a spiritual being to be simple, i.e.,
without parts"), and proceeds to show that this law
applies to all or certain beings seen to be
comprised under the extension of the law (for
instance, "the human soul, belonging as it does to
the category of spiritual beings, is endowed with
simplicity"). The law, which is the foundation of
the syllogism, belongs to either class of
judgments, as it is dependent upon or independent
of experience. The result of a syllogism is a new
judgment, so that the judgment is the unit of
logical construction, with which all knowledge
begins and ends.
D. Scientific
systematization and its methods
1. First
principles of each science.
Isolated reasonings could not make a science. In
their turn they are connected together like the
links of a chain: each finds its justification in a
previous inference. But there must be a beginning
to the process, -- there must be something from
which the whole chain may hang. An infinite
regression would render all knowledge
impossible.
There are therefore at the base of each
and every science certain indemonstrable
judgments, known as the first principles of the
science in question. They formulate certain very
simple and evident relationships, and are derived
from the subject matter of the science. Their
enunciation may or may not presuppose observation,
according to the nature of the subject matter of
the science. Thus that 1 + 1 = 2 is a principle of
arithmetic; that the group life is for the sake of
the individual members is a principle of social
science. These principles, which do not admit of
further definition or demonstration, constitute the
limits and boundaries of each science. They consist
generally of 'definitions,' inasmuch as they make
clear what is the object studied by each particular
science. We see, then, that besides the governing
principles of all knowledge which are
common to every science, like the principle of
contradiction, each science has its
own fundamental principles
[1].
2. Material
and formal object of each science.
The numerous reasonings which go to make up a
science, together with its definitions and the
first principles which constitute its basis, for
one coherent whole, a unified system. The unity
which runs through the whole, and is more or less
evident according to the importance of each
section, depends on the 'formal object' of the
science. What does this mean?
The Schoolmen point out that in every science
there is room to distinguish between the things
themselves which are studied -- the raw material of
the science, its 'material object' -- and the point
of view, or aspect from which these materials are
considered ('formal object'). For example, the
human body is the material studied by physiology,
but this only considers it from one point of view,
namely, that of the functions exercised by its
organs. This point of view is grasped as a result
of abstraction, so that abstraction (II, C) is the
generative process which underlies all science.
Every reasoning or principle must express in
some way the formal object of the science in
question. Thus in physiology, every doctrine ought
to be concerned with the functional role of organs.
It is the 'formal object' which gives each science
its distinctive character, and makes it what it is,
-- hence the designation of formal
object [2]. Whence it follows, that two
sciences may possess the same subject matter, may
have the same 'raw material,' but unless they are
to be identical, each must study this material from
a distinct and separate point of view. Thus anatomy
also studies the human body, but from the point of
view of its structure. If it were to concern itself
with functions, it would trespass upon and identify
itself with physiology, and one or the other would
have to disappear.
Thomas applies this theory of the specification
of sciences to philosophy and theology, which have
to some extent the same material object, but of
which the formal points of view are quite distinct.
"A difference in the point of view from which the
mind contemplates the object entails a diversity in
the branches of knowledge (diversa ratio
cognoscibilis diversitatem scientiarum
inducit). The astronomer and the physicist both
may prove the same conclusion, -- that the earth,
for instance, is round: the astronomer by means of
mathematics (i.e., abstracting from matter), but
the physicist by means of matter itself. Hence
there is no reason why those things which may be
learned from philosophical science, so far as they
can be known by natural reason, may not also be
taught us by another science so far as they fall
within revelation. Hence theology included in
Sacred Doctrine differs in kind from that theology
which is part of philosophy" [3].
This justifies what we said at the beginning,
that scholastic Philosophy is quite different from
scholastic Theology, despite the relation between
them, of which there will be made a brief mention
toward the end of this work.
On these notions of the formal and material
object, the scholastics rest their classification
of the sciences whether particular or general,
i.e., philosophical, and their division of
philosophy (XVIII).
Notes:
1. Scheme of scientific judgments. If we bear in
mind that there are two types of judgments, namely
judgments of the ideal and of the existential order
(IV, B), and that the first type includes two
classes, we may establish the following scheme of
judgments which are involved in any science.
A. Axioms, relating to all being, and common to
all the sciences: these are judgments of the ideal
order, especially of the second class.
B. Judgments proper to certain sciences.
- 1. Deductive sciences: judgments of the
ideal order (both classes). They are either (a)
the fundamental principles of the science in
question; immediate and self-evident judgments
(example, 1 = 1). (b) mediate, or calling for
demonstration, e.g., the complicated theorems of
geometry.
- 2. Experimental sciences: judgments of the
existential order. (a) immediate or
self-evident, e.g., "I think, therefore I
exist." (b) mediate, e.g., "water boils at 100
degrees C."
2. In formal, we find the determination,
which belongs to the forma.
3. Summa Theol., Ia, q. 1, art. 1.
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