The Art Of Logical Thinking
THE ART OF LOGICAL THINKINGCHAPTER I. REASONINGCHAPTER II. THE PROCESS OF REASONINGCHAPTER III. THE CONCEPTCHAPTER IV. THE USE OF CONCEPTSCHAPTER V. CONCEPTS AND IMAGESCHAPTER VI. TERMSCHAPTER VII. THE MEANING OF TERMSCHAPTER VIII. JUDGMENTSCHAPTER IX. PROPOSITIONSCHAPTER X. IMMEDIATE REASONINGCHAPTER XI. INDUCTIVE REASONINGCHAPTER XII. REASONING BY INDUCTIONCHAPTER XIII. THEORY AND HYPOTHESESCHAPTER XIV. MAKING AND TESTING HYPOTHESESCHAPTER XV. DEDUCTIVE REASONINGCHAPTER XVI. THE SYLLOGISMCHAPTER XVII. VARIETIES OF SYLLOGISMSCHAPTER XVIII. REASONING BY ANALOGYCHAPTER XIX. FALLACIESCopyright
THE ART OF LOGICAL THINKING
William Walker Atkinson
CHAPTER I. REASONING
"Reasoning" is defined as: "The act, process or art of exercising
the faculty of reason; the act or faculty of employing reason in
argument; argumentation, ratiocination; reasoning power;
disputation, discussion, argumentation." Stewart says: "The word
reason itself is far from being precise in its meaning. In common
and popular discourse it denotes that power by which we distinguish
truth from falsehood, and right from wrong, and by which we are
enabled to combine means for the attainment of particular
ends."
By the employment of the reasoning faculties of the mind we compare
objects presented to the mind as percepts or concepts, taking up
the "raw materials" of thought and weaving them into more complex
and elaborate mental fabrics which we call abstract and general
ideas of truth. Brooks says: "It is the thinking power of the mind;
the faculty which gives us what has been called thought-knowledge,
in distinction from sense-knowledge. It may be regarded as the
mental architect among the faculties; it transforms the material
furnished by the senses ... into new products, and thus builds up
the temples of science and philosophy." The last-mentioned
authority adds: "Its products are twofold, ideas and thoughts. An
idea is a mental product which when expressed in words does not
give a proposition; a thought is a mental product which embraces
the relation of two or more ideas. The ideas of the understanding
are of two general classes; abstract ideas and general ideas. The
thoughts are also of two general classes; those pertaining to
contingent truth and those pertaining to necessary truth. In
contingent truth, we have facts, or immediate judgments, and
general truths including laws and causes, derived from particular
facts; in necessary truth we have axioms, or self-evident truths,
and the truths derived from them by reasoning, called
theorems."
In inviting you to consider the processes of reasoning, we are
irresistibly reminded of the old story of one of Moliere's plays in
which one of the characters expresses surprise on learning that he
"had been talking prose for forty years without knowing it." As
Jevons says in mentioning this: "Ninety-nine people out of a
hundred might be equally surprised on hearing that they had been
converting propositions, syllogizing, falling into paralogisms,
framing hypotheses and making classifications with genera and
species. If asked whether they were logicians, they would probably
answer, No! They would be partly right; for I believe that a large
number even of educated persons have no clear idea of what logic
is. Yet, in a certain way, every one must have been a logician
since he began to speak."
So, in asking you to consider the processes of reasoning we are not
assuming that you never have reasoned—on the contrary we are fully
aware that you in connection with every other person, have reasoned
all your mature life. That is not the question. While everyone
reasons, the fact is equally true that the majority of persons
reason incorrectly. Many persons reason along lines far from
correct and scientific, and suffer therefor and thereby. Some
writers have claimed that the majority of persons are incapable of
even fairly correct reasoning, pointing to the absurd ideas
entertained by the masses of people as a proof of the statement.
These writers are probably a little radical in their views and
statements, but one is often struck with wonder at the evidences of
incapacity for interpreting facts and impressions on the part of
the general public. The masses of people accept the most absurd
ideas as truth, providing they are gravely asserted by some one
claiming authority. The most illogical ideas are accepted without
dispute or examination, providing they are stated solemnly and
authoritatively. Particularly in the respective fields of religion
and politics do we find this blind acceptance of illogical ideas by
the multitude. Mere assertion by the leaders seems sufficient for
the multitude of followers to acquiesce.
In order to reason correctly it is not merely necessary to have a
good intellect. An athlete may have the proper proportions, good
framework, and symmetrical muscles, but he cannot expect to cope
with others of his kind unless he has learned to develop those
muscles and to use them to the best advantage. And, in the same
way, the man who wishes to reason correctly must develop his
intellectual faculties and must also learn the art of using them to
the best advantage. Otherwise he will waste his mental energy and
will be placed at a disadvantage when confronted with a trained
logician in argument or debate. One who has witnessed a debate or
argument between two men equally strong intellectually, one of whom
is a trained logician and the other lacking this advantage, will
never forget the impression produced upon him by the unequal
struggle. The conflict is like that of a powerful wrestler,
untrained in the little tricks and turns of the science, in the
various principles of applying force in a certain way at a certain
time, at a certain place, with a trained and experienced wrestler.
Or of a conflict between a muscular giant untrained in the art of
boxing, when confronted with a trained and experienced exponent of
"the manly art." The result of any such conflict is assured in
advance. Therefore, everyone should refuse to rest content without
a knowledge of the art of reasoning correctly, for otherwise he
places himself under a heavy handicap in the race for success, and
allows others, perhaps less well-equipped mentally, to have a
decided advantage over him.
Jevons says in this connection: "To be a good logician is, however,
far more valuable than to be a good athlete; because logic teaches
us to reason well, and reasoning gives us knowledge, and knowledge,
as Lord Bacon said, is power. As athletes, men cannot for a moment
compare with horses or tigers or monkeys. Yet, with the power of
knowledge, men tame horses and shoot tigers and despise monkeys.
The weakest framework with the most logical mind will conquer in
the end, because it is easy to foresee the future, to calculate the
result of actions, to avoid mistakes which might be fatal, and to
discover the means of doing things which seemed impossible. If such
little creatures as ants had better brains than men, they would
either destroy men or make them into slaves. It is true that we
cannot use our eyes and ears without getting some kind of
knowledge, and the brute animals can do the same. But what gives
power is the deeper knowledge called Science. People may see, and
hear, and feel all their lives without really learning the nature
of things they see. But reason is the mind's eye, and enables us to
see why things are, and when and how events may be made to happen
or not to happen. The logician endeavors to learn exactly what this
reason is which makes the power of men. We all, as I have said,
must reason well or ill, but logic is the science of reasoning and
enables us to distinguish between the good reasoning which leads to
truth, and the bad reasoning which every day betrays people into
error and misfortune."
In this volume we hope to be able to point out the methods and
principles of correctly using the reasoning faculties of the mind,
in a plain, simple manner, devoid of useless technicalities and
academic discussion. We shall adhere, in the main, to the
principles established by the best of the authorities of the old
school of psychology, blending the same with those advanced by the
best authorities of the New Psychology. No attempt to make of this
book a school text-book shall be made, for our sole object and aim
is to bring this important subject before the general public
composed of people who have neither the time nor inclination to
indulge in technical discussion nor academic hair-splitting, but
who desire to understand the underlying working principles of the
Laws of Reasoning.
CHAPTER II. THE PROCESS OF REASONING
The processes of Reasoning may be said to comprise four general
stages or steps, as follows:
I. Abstraction, by which is meant the process of drawing off and
setting aside from an object, person or thing, a quality or
attribute, and making of it a distinct object of thought. For
instance, if I perceive in a lion the quality of strength, and am
able to think of this quality abstractly and independently of the
animal—if the term strength has an actual mental meaning to me,
independent of the lion—then I have abstracted that quality; the
thinking thereof is an act of abstraction; and the thought-idea
itself is an abstract idea. Some writers hold that these abstract
ideas are realities, and "not mere figments of fancy." As Brooks
says: "The rose dies, but my idea of its color and fragrance
remains." Other authorities regard Abstraction as but an act of
attention concentrated upon but the particular quality to the
exclusion of others, and that the abstract idea has no existence
apart from the general idea of the object in which it is included.
Sir William Hamilton says: "We can rivet our attention on some
particular mode of a thing, as its smell, its color, its figure,
its size, etc., and abstract it from the others. This may be called
Modal Abstraction. The abstraction we have now been considering is
performed on individual objects, and is consequently particular.
There is nothing necessarily connected with generalization in
abstraction; generalization is indeed dependent on abstraction,
which it supposes; but abstraction does not involve
generalization."
II. Generalization, by which is meant the process of forming
Concepts or General Ideas. It acts in the direction of apprehending
the common qualities of objects, persons and things, and combining
and uniting them into a single notion or conception which will
comprehend and include them all. A General Idea or Concept differs
from a particular idea in that it includes within itself the
qualities of the particular and other particulars, and accordingly
may be applied to any one of these particulars as well as to the
general class. For instance, one may have a particular idea of some
particular horse, which applies only to that particular horse. He
may also have a General Idea of horse, in the generic or class
sense, which idea applies not only to the general class of horse
but also to each and every horse which is included in that class.
The expression of Generalization or Conception is called a
Concept.
III. Judgment, by which is meant the process of comparing two
objects, persons or things, one with another, and thus perceiving
their agreement or disagreement. Thus we may compare the two
concepts horse and animal, and perceiving a certain agreement
between them we form the judgment that: "A horse is an animal;" or
comparing horse and cow, and perceiving their disagreement, we form
the judgment: "A horse is not a cow." The expression of a judgment
is called a Proposition.
IV. Reasoning, by which is meant the process of comparing two
objects, persons or things, through their relation to a third
object, person or thing. Thus we may reason (a) that all mammals
are animals; (b) that a horse is a mammal; (c) that, therefore, a
horse is an animal; the result of the reasoning being the statement
that: "A horse is an animal." The most fundamental principle of
reasoning, therefore, consists in the comparing of two objects of
thought through and by means of their relation to a third object.
The natural form of expression of this process of Reasoning is
called a Syllogism.
It will be seen that these four processes of reasoning necessitate
the employment of the processes of Analysis and Synthesis,
respectively. Analysis means a separating of an object of thought
into its constituent parts, qualities or relations. Synthesis means
the combining of the qualities, parts or relations of an object of
thought into a composite whole. These two processes are found in
all processes of Reasoning. Abstraction is principally analytic;
Generalization or Conception chiefly synthetic; Judgment is either
or both analytic or synthetic; Reasoning is either a synthesis of
particulars in Induction, or an evolution of the particular from
the general in Deduction.
There are two great classes of Reasoning; viz., (1) Inductive
Reasoning, or the inference of general truths from particular
truths; and (2) Deductive Reasoning, or the inference of particular
truths from general truths.
Inductive Reasoning proceeds by discovering a general truth from
particular truths. For instance, from the particular truths that
individual men die we discover the general truth that "All men must
die;" or from observing that in all observed instances ice melts at
a certain temperature, we may infer that "All ice melts at a
certain temperature." Inductive Reasoning proceeds from the known
to the unknown. It is essentially a synthetic process. It seeks to
discover general laws from particular facts.
Deductive Reasoning proceeds by discovering particular truths from
general truths. Thus we reason that as all men die, John Smith,
being a man, must die; or, that as all ice melts at a certain
temperature, it follows that the particular piece of ice under
consideration will melt at that certain temperature. Deductive
Reasoning is therefore seen to be essentially an analytical
process.
Mills says of Inductive Reasoning: "The inductive method of the
ancients consisted in ascribing the character of general truths to
all propositions which are true in all the instances of which we
have knowledge. Bacon exposed the insufficiency of this method, and
physical investigation has now far outgrown the Baconian
conception.... Induction, then, is that operation by which we infer
that what we know to be true in a particular case or cases, will be
true in all cases which resemble the former in certain assignable
respects. In other words, induction is the process by which we
conclude that what is true of certain individuals of a class is
true of the whole class, or that what is true at certain times will
be true in similar circumstances at all times."
Regarding Deductive Reasoning, a writer says: "Deductive Reasoning
is that process of reasoning by which we arrive at the necessary
consequences, starting from admitted or established premises."
Brooks says: "The general truths from which we reason to
particulars are derived from several distinct sources. Some are
intuitive, as the axioms of mathematics or logic. Some of them are
derived from induction.... Some of them are merely hypothetical, as
in the investigation of the physical sciences. Many of the
hypotheses and theories of the physical sciences are used as
general truth for deductive reasoning; as the theory of
gravitation, the theory of light; etc. Reasoning from the theory of
universal gravitation, Leverrier discovered the position of a new
planet in the heavens before it had been discovered by human
eyes."
Halleck points out the interdependence of Inductive and Deductive
Reasoning in the following words: "Man has to find out through his
own experience, or that of others, the major premises from which he
argues or draws his conclusions. By induction we examine what seems
to us a sufficient number of individual cases. We then conclude
that the rest of these cases, which we have not examined, will obey
the same general laws.... The premise, 'All cows chew the cud,' was
laid down after a certain number of cows had been examined. If we
were to see a cow twenty years hence, we should expect that she
chewed her cud.... After Induction has classified certain phenomena
and thus given us a major premise, we proceed deductively to apply
the inference to any new specimen that can be shown to belong to
that class."
The several steps of Deductive Reasoning shall now be considered in
turn as we proceed.
CHAPTER III. THE CONCEPT
In considering the process of thinking, we must classify the
several steps or stages of thought that we may examine each in
detail for the purpose of comprehending them combined as a whole.
In actual thinking these several steps or stages are not clearly
separated in consciousness, so that each stands out clear and
distinct from the preceding and succeeding steps or stages, but, on
the contrary, they blend and shade into each other so that it is
often difficult to draw a clear dividing line. The first step or
stage in the process of thinking is that which is called a
concept.
A concept is a mental representation of anything. Prof. Wm. James
says: "The function by which we mark off, discriminate, draw a line
around, and identify a numerically distinct subject of discourse is
called conception." There are five stages or steps in each concept,
as follows:
I. Presentation. Before a concept may be formed there must first be
a presentation of the material from which the concept is to be
formed. If we wish to form the concept, animal, we must first have
perceived an animal, probably several kinds of animals—horses,
dogs, cats, cows, pigs, lions, tigers, etc. We must also have
received impressions from the sight of these animals which may be
reproduced by the memory—represented to the mind. In order that we
may have a full concept of animal we should have perceived every
kind of animal, for otherwise there would be some elements of the
full concept lacking. Accordingly it is practically impossible to
have a full concept of anything. The greater the opportunities for
perception the greater will be the opportunity for conception. In
other books of this series we have spoken of the value and
importance of the attention and of clear and full perception.
Without an active employment of the attention, it is impossible to
receive a clear perception of anything; and unless the perception
has been clear, it is impossible for the mind to form a clear
concept of the thing perceived. As Sir Wm. Hamilton has said: "An
act of attention, that is an act of concentration, seems thus
necessary to every exertion of consciousness, as a certain
contraction of the pupil is requisite to every exertion of
vision.... Attention, then, is to consciousness what the
contraction of the pupil is to sight, or to the eye of the mind
what the microscope or telescope is to the bodily eye.... It
constitutes the half of all intellectual power." And Sir B. Brodie
said: "It is attention, much more than in the abstract power of
reasoning, which constitutes the vast difference which exists
between minds of different individuals." And as Dr. Beattie says:
"The force with which anything strikes the mind is generally in
proportion to the degree of attention bestowed upon it."