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THE
PROBLEM OF KNOWLEDGE
A Brief
Introduction to Epistemology
by Jonathan Dolhenty, Ph.D.
PART
FIVE
- The Formation of
Ideas
- Idea and Sense
Image
DIAGRAMS:
THE NATURE OF
IDEAS
Ideas are the building blocks of knowledge.
Judgments, which are expressed in sentences called
propositions, are made up of ideas. A judgment is
an act of the mind pronouncing the agreement or
disagreement of ideas among themselves. We need,
therefore, to direct our attention to what ideas
are and how are they formed.
The Formation
of Ideas
We can begin to understand the nature of the
idea by taking a look at the process we use in
forming ideas. The process which is described here
is a philosophical process, from the viewpoint of
common sense critically examined, and not one
described in the terms of the physical and
biological sciences. So pay particular attention to
the definition of the words used.
How We Form
Ideas
All knowledge begins with the senses. We
perceive many objects out there in the world which
are presented to our various senses. For example,
we see a lump of sugar and say it is white in
color. We touch it with our fingers and notice it
is granular in texture. We taste it and discover it
is sweet. This combination of white, granular, and
sweet forms a sense image in us which is retained
in our imagination and memory. We can recall this
image even when the object is not present before
us. If we hear the word "sugar," we can recall the
image of sugar. (Consult the chart below on
Sense
Knowledge.)
The same thing applies to other words in a
similar way. When we hear words like "mountain,"
"dog," "John Wayne," and so forth, we can recall
their image as long as we have perceived them in
fact or have heard or read about them. When my
little dog, Ming, hears the word "treat" he
immediately begins to jump and bark. This is the
word he has associated with the little dog bones he
gets now and then as a special favor. By means of
his memory and imagination, he recalls the image of
the bones that he has previously experienced.
This sense image of the imagination is the first
step in the formation of an idea.
Now that the sense image is in the imagination,
the mind begins to think and the intellect gives
its attention to the sense image in order to make
its own representation of the object. It does this
by a process called abstraction. Let's take an
example of this process in action so this matter
will be clear.
Through experience we come into contact with
objects which we designate by the word "dog." One
thing we discover right away is that there are a
great many differences among the dogs we
experience. Some are large, some are small. Some
are fat, some are thin. Some are black, some are
brown, and some are another color. Some are old,
some are young. Some are male dogs, some are female
dogs.
The intellect notices these differences and
discovers that some of these characteristics change
or disappear, while others take their place. But
the intellect also realizes that some
characteristics remain intact throughout all the
changes. For instance, all dogs have a body, take
in nourishment and water, and have physical senses
enabling them to experience the world around them.
The intellect notices that dogs are living,
sentient, and conscious substances. The word
"substances" means a thing that exists in itself.
Dogs are substances, as are human beings, desks,
rocks, plants, and so forth.
It doesn't matter what color a dog is or whether
the dog is large or small or has a mean
temperament. There are some things that make a dog
to be a dog and those things we call the essential
elements which constitute his nature. A dog must be
sentient to be a dog. This is a characteristic
essential to be a dog. A dog is a living substance
made from chemical materials. These are essential
to be a dog.
Once the sense image is formed and registered in
the imagination and memory, the intellect strips
the individual dog of all the nonessential
characteristics, retains the essential
characteristics only, forming them into what is
called an intellectual image. The intellectual
image of a dog is that it is a sentient, living,
bodily substance. This intellectual image of a dog
is the idea of dog.
We form the idea of "man" or "human being" the
same way. Our experience brings us into contact
with many beings which we designate by the word
"man." We notice differences among these many
beings but we also recognize some similarities.
When a particular human being is sensed, a sense
image is formed and from this sense image the
intellect abstracts the essential characteristics,
forming an intellectual image or idea of what is
necessary to be a "man" or "human being."
Human beings differ in many nonessential
characteristics. Just like dogs, some human beings
are tall or short, fat or thin, white or black or
brown, healthy or diseased, and so on. But what is
it that all human beings have in common? What are
the essential characteristics to be a human being?
Certain characteristics are obvious. Human beings
are a substance, that is, an independently existing
being, and they are made of living material and are
sentient. All human beings must have at least these
essential characteristics to be human. But dogs and
other animals also have these characteristics. So
how do we differentiate human beings from other
animals?
There is one essential characteristic that human
beings possess that animals do not. (It should be
noted here that while human beings share certain
essential characteristics with other animals, human
beings here are considered to be different in kind
from other animals.) This essential characteristic
is rationality. Rationality refers to the ability
to form abstract ideas, to reason intellectually,
to form moral judgments, and so on. So far as we
know, animals do not possess these abilities.
The essential characteristics of a human being
are that of a substance that is material, living,
sentient, and rational. Since animals are also
substances that are material, living, and sentient,
and the only difference between animals and human
beings is the essential characteristic of
rationality, philosophers have traditionally
referred to the human being as a rational
animal.
Let's consider plants for a minute. We
experience a variety of plants we call "trees." How
do we form the idea of a tree? Once the sense
images of these plants is available to our
intellect, it ignores the differences among them as
to size, shape, color, and other nonessential
characteristics. The intellect retains the
essential elements, those things that are found in
all trees, and combines them into a single
intellectual image or idea of "tree."
We are now ready to define the word "idea." An
idea is the intellectual image or representation of
a thing. Another word for "idea" is "concept."
Idea and
Sense Image
The idea must not be confused with the sense
image. The sense image is formed in the imagination
as a result of sense data. We see, hear, feel,
smell, or taste something and form a sense image.
The idea, on the other hand, is formed in the
intellect.
The sense image is always concrete, individual,
particular. We cannot form a sense image of all
members of a class of individual objects. Our
imagination can make a general picture of a black
dog, for instance, but it cannot make a sense image
that will fit a black dog and a white dog at the
same time. The sense image will fit either a black
dog (a particular) or a white dog (another
particular) but not both.
No single sense image of "man" or "human being"
can adequately fit at the same time a baby, a
teenager, an old woman, Thomas Jefferson, or
Socrates. No single sense image of "animal" can fit
an amoeba, a spider, an elephant, a salmon, and a
dinosaur. The reason for this should be clear. The
senses picture single, concrete, particularized
objects. The imagination makes the sense images
from these sense pictures. So the sense image must
also be concrete, individual, and particular.
The idea or concept is different. The idea can
apply equally to an individual and to a class of
individuals and even to a number of classes of
individuals. We say the idea is universal. The idea
"human being" can fit a baby, a teenager, an old
woman, Thomas Jefferson, and Socrates. No problem.
The idea "dog" can fit a German shepherd, a
dachshund, a great Dane, and even my little Lhasa
Apso, Ming. No problem. The idea of "human being"
and "dog" can apply to a single individual of the
class or to the entire class of individuals
itself.
Another difference between the sense image and
the idea is that the sense image becomes very vague
and indistinct when it becomes complex and has to
deal with a multitude of detail. We can form a
sense image of five people in a row. But to imagine
five million in a row is virtually impossible. The
idea of five million people, however, presents no
problems and is as clear as the idea of five
people.
Still another difference between the sense image
and the idea is that we can have a very clear idea
of some things for which we cannot reasonably form
a sense image. For example, we often talk about
such things as the "law," or virtue, or life, or
justice, or, for that matter, logic. How does one
form a sense image of such things? We do not even
attempt to do so. We simply think and talk about
virtue, justice, logic, and so forth, without
worrying about a sense image of them.
It is important to realize that the imagination
and intellect, the sense image and the idea, are in
close harmony. The intellect wouldn't have anything
in it if it were not for the senses. The intellect
is dependent on the imagination to furnish it with
materials for ideas. All knowledge begins in the
senses and there is nothing in the intellect that
at one time was not derived in some form from sense
data. Ideas are totally distinct from sense images
yet dependent on them. (Consult the chart below on
The Process of
Abstraction.)
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SENSE
KNOWLEDGE
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INTERNAL
SENSES
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EXTERNAL
SENSES
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Unifying
Sense
The power to co-ordinate the different
aspects of objects brought in by the
external senses
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Sight
Hearing
Smell
Touch
Taste
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Memory
The power to store up and recall past
objects and states of consciousness and
recognize them as having been present in
former experiences
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Imagination
The power to form mental images of
perceived objects and the ability to
reproduce these images even when the
perceived objects are absent
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ALL HUMAN
KNOWLEDGE
HAS ITS STARTING
POINT IN SENSATION
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Estimative
Sense
The power to perceive the useful or
harmful character of particular things for
our well-being
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SENSE
KNOWLEDGE IS:
INDIVIDUAL
PARTICULAR
CONCRETE
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Return to reading
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THE
PROCESS OF ABSTRACTION
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OBJECT
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The external object sends forth
certain forms of energy which are received
by the senses. At this point we are
perceiving objects and are said to
experience perceptions.
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Sight - Touch - Taste - Hearing
- Smell
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UNIFYING
SENSE
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IMAGINATION
Sense image stored as a trace
or disposition. Can be later
reviewed.
MEMORY
Sense image stored as to date
and localizes past
experiences.
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SENSE
IMAGE
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This is a total sensory impression
and a completed cognitional image. It is
psychical or mental representation of the
external thing. It is concrete and
individualized.
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IMAGE
INTERFACE
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The essential elements of the
object are abstracted from the concrete
conditions in which they are found in the
sense image.
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These abstracted elements are
presented to the intellect.
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INTELLECT
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The intellect goes into action and
mentally expresses this intelligible
content in conceptual terms. It forms an
idea or concept in an abstract and
universal manner. The concept is then
stored away in the intellectual memory for
future recall and identification.
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CONCEPT
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