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THE
PROBLEM OF KNOWLEDGE
A Brief
Introduction to Epistemology
by Jonathan Dolhenty, Ph.D.
PART
TWO
- Convictions Based
on Sense Perception
- Convictions Based
on Our Intellect
- Different Classes
of Truths
THE NATURE OF
KNOWLEDGE (Con't)
No one seriously doubts that human beings
possess what is termed "knowledge" considered as a
subjective state of mind. We all know that we know
something. We have spontaneous convictions which
seem to us to be obvious facts. We don't question
them. They produce in us a state of subjective
certitude.
This is not enough, however, for the
professional philosopher and should not be enough
for the serious thinker. What we should want is to
establish that this subjective certitude is
grounded on objective reality. This is a vital
question. This problem has generally been called
the problem of knowledge or the epistemological
problem. Epistemology is that branch of philosophy
which deals with the validity of knowledge and the
criterion of truth.
Convictions
Based on Sense Perception
We begin with sense-perceptions, those phenomena
which no one can seriously deny. Our senses of
sight, taste, smell, hearing and touch are our
first contact with an outside reality. The ordinary
person is certain that these senses reveal to him
his own body and other bodies which are real in the
world of physical objects.
Besides these senses which acquaint us with the
outside world, the human organism also possesses
what we may designate as internal senses. They
enable us to apprehend facts of a subjective
character in a sensuous manner. For instance, the
common or central sense makes us aware of our
sense-acts, is the seat of sense-consciousness, and
notifies us of the presence of the perceptive acts
mentioned above. The central sense allows us to
distinguish in a concrete way between the various
sense organs and sense perceptions and to locate
them in the bodily system.
There is also an internal sense called
imagination. The imagination uses the material
supplied by our sense-perceptions to form images of
its own fashioning, such as when we dream. It is
through the imagination that we create, for
example, a world of fantasy which exists nowhere
but in our mind.
There is also sense-memory which recalls
perceptions and events and recognizes them
concretely as having been experienced before. We
can remember persons and objects and the time and
place of seeing them.
There is also a sense sometimes called instinct
which does not play a prominent role in man's life,
but is found to play a dominant part in the life of
the "lower" animals. The influence of instinct is
noticed primarily in actions which are necessary
for the preservation of the individual and of the
race.
All these senses convey knowledge of the reality
of the physical world in some form or other and are
the starting point in discussing intellectual
knowledge. Again, no one seriously questions the
spontaneous convictions which arise as a result of
our sense-perceptions.
Convictions
Based on Our Intellect
Now we come to the matter of intellectual
knowledge. This is distinctly "human" knowledge
because we do not find it in other than the human
being. Intellectual knowledge appears in three
phases: ideas, judgments and inferences. The
existence of these three phases is a fact of human
existence and they lie at the very core of the
problem of knowledge.
The definition of idea is that it is the
intellectual representation of a thing. It is
important to note that an idea of a thing is very
different from a sense-perception of that thing.
The senses perceive a thing in its concrete
individuality with all the peculiar traits and
characteristics which make this thing to be this
thing and differentiate this thing from every other
thing. An idea, however, apprehends a thing in
those essential attributes which the thing has in
common with all other things of the same class or
species. It leaves aside all the individualizing
and differentiating marks peculiar to the thing
itself.
Let's look at a simple example to illustrate the
above. I see a maple tree of a certain size, age,
color, texture, shape and so on. My picture of this
particular maple tree is the result of perception
through the sense of sight. But the idea of tree is
substantially different. I disregard all the
peculiar elements of the individual tree and
apprehend instead those essential attributes which
it has in common with all other trees. My intellect
combines them into a single intellectual image or
idea, namely, a tree is a "woody perennial plant
with a single main stem, usually about at least ten
feet high." Sense-perception represents the tree in
the concrete; the idea represents the tree in the
abstract.
Judgments
The definition of judgment is that it is an act
of the mind affirming or denying one idea of
another. Three factors are involved in the making
of a judgment:
- (1) two ideas which are known,
- (2) the mutual comparison of these two
ideas, and
- (3) the mental pronouncement of their
agreement or disagreement.
The intellect, for example, consciously
apprehends and compares the ideas "tree" and
"plant" and finds they agree. Then it pronounces
this agreement in a judgment, "the tree is a
plant." Conversely, comparing the ideas "tree" and
"animal," the intellect perceives they do not agree
and makes the judgment, "the tree is not an
animal." If the assertion in the judgment is
correctly made, it is a true judgment. If it is
incorrectly made, it is false. Thus judgments
contain truth or error.
The judgment is extremely important in the
problem of knowledge because it contains the
characteristic of truth or error. Sense-perceptions
present or represent things concretely and ideas
represent the essence of things abstractly.
Judgments, however, claim to express the truth
about reality as it actually is in itself.
Inferences
The intellect does not always perceive the
agreement or disagreement between two ideas by a
direct comparison of the two. It cannot always make
an immediate judgment about the two ideas. If,
however, the mind can bring in a third known idea
with which, upon comparison, the mind finds the two
ideas to agree, then the intellect is justified in
saying that these two ideas agree with each other.
This is inference or reasoning and is defined as
the mental process by which, from certain truths
already known, the mind passes to another truth
distinct from these but necessarily following from
them.
That we reason and make inferences is a fact of
everyday experience. And we are generally convinced
that these inferences, since they consist of
judgments and lead to a final judgment, are a valid
form of knowledge and contain truth regarding
reality as it really is. No matter the topic of
debate, if we are sincere and not playing mere
mind-games, we always debate with the conviction
that these arguments can lead to truth and valid
knowledge.
Different
Classes of Truths
Truth lies in the judgment. But not all truths
are of equal value to man. Let's take a look at the
various classes of truths.
Analytical
Judgments
We possess a class of truths which are
analytical judgments. These judgments contain
truths directly evident to the intellect through a
comparison or analysis of the ideas of the
judgment. There is no immediate sense-perception
and no logical reasoning. They do not need a
demonstration to verify them.
For example, the judgment that "the whole is
greater than any of its parts," is known directly
by the intellect through an analysis of the ideas
contained within the judgment. No proof is
necessary and, indeed, in many cases, no proof is
possible. There are also some axioms which are
judgments of the analytical variety and constitute
the basic principles which are at the bottom of all
knowledge. Axioms like the principle of identity (A
is A) and the principle of contradiction are used
in every act of reasoning and are universally,
necessarily and absolutely true.
Immediate
Judgments
We also possess a class of truths which are
immediate judgments containing truths which are
derived from direct experience through internal and
external sense-perceptions. Such judgments refer to
individual concrete facts, events, persons and
objects.
For example, the judgment that "that cat is
running," cannot be known simply by comparing or
analyzing the ideas of "cat" and "running." The cat
could just as well be playing, scratching or
whatever. That I can actually judge "that cat is
running," is because of my actual experience of
seeing the cat run. This type of judgment is not
analytical, it is synthetic. It contains empirical
truths based on direct experience. Such judgments
are not considered to be universal, necessary or
absolute. They are contingent and experiential
truths which may change with changing
circumstances.
Mediate Judgments of
Deduction
There is another class of truths called mediate
judgments which are deduced by inference or
reasoning from first principles. These judgments
are based on self-evident first principles or
axioms, but are not self-evident themselves. It
takes a process of reasoning to show that such
judgments follow necessarily from the axioms.
For example, the judgment that 38,400 is
divisible by 2,560 fifteen times is not in itself
immediately observed. If, however, we perform the
division or multiply 2,560 by 15, we can prove the
truth of the judgment. Mathematical deductions are
examples of mediate judgments deduced by inference.
Provided that our reasoning powers are essentially
valid, mediate judgments derived from first
principles are universally, necessarily and
absolutely true.
Mediate Judgments of
Induction
A fourth class of truths are mediate judgments
which are the result of an inductive process
generalizing the individual, concrete data of
direct sense-perception into laws of a universal
character. The laws and generalizations of
experimental science are of this type.
For example, the judgment that "the boiling
point of water is plus 212 degrees F. at sea
level," is an example of a generalization (or law)
made through an inductive process. This process
depends on careful investigation and extensive
experimentation.
The above discussion constitutes a survey of the
sources and main facts of knowledge as revealed in
the spontaneous conviction of men. There is one
trait characteristic of these spontaneous
convictions, namely, our knowledge is a faithful
and genuine representation of reality as it is in
itself.
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