Nature of Knowledge: Convictions & Classes of Truth – Dolhenty

A Brief Introduction to Epistemology
By Jonathan Dolhenty, Ph.D.


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.


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.


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.

Self-Educated American recommends: Great Books of the Western World

The late Dr. Jonathan Dolhenty was the Founder and President of The Center for Applied Philosophy and the Radical Academy, and is Honorary Philosophy Editor at Self-Educated American. Self-Educated American has adopted these projects beginning with a republishing and preserving of all of Dr. Dolhenty’s work.

Copyright ©1992 -2011 The Radical Academy. Copyright renewed in 2011 -2013 © The Radical Academy (a project of Self-Educated American).