The Nature of Knowledge: Fundamental Ideas, Truth & Error, Motive of Certitude

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


Knowledge is a primary fact of human life and experience. Everyone understands what it means “to know.” We immediately encounter difficulties, however, when we try to explain and analyze this idea. The concept of knowledge eludes every effort at an exact definition because it is a primary fact of experience. We can point out certain characteristics of and adduce definite instances of knowledge, but we cannot really define it exactly.


Fundamental Ideas

There are three elements which enter into knowledge:

  • (1) the knowing subject,
  • (2) the known object, and
  • (3) the mental act of knowing, which is called cognition.

The subject is obviously the one who knows, the knower in this case is man, and taken individually, the ego or I myself.

The object of knowledge is anything and everything that is, or becomes, or can be, known by man. The objects of man’s knowledge are himself, conscious states of his self, and also realities other than himself. Every act of knowledge must be knowledge of something and refer to some object.

The object becomes known to the subject by an act of knowing. This takes place in the subject or knower and is a unitive act in as much as it brings the object and the subject into contact with each other.


Truth and Error

Knowledge has the quality of truth and error and it is only in the act of knowledge that we have truth and error. Truth and error enter into our knowledge when this knowledge is expressed in judgments. Judgments are statements where we affirm or deny something of something else. If what we affirm is really so as we affirm it to be, we have truth; but if it is not really so, we have error.

For instance, I look at someone’s pet and I say, “This is a cat and not a dog.” I both affirm and deny something here of the pet I’m seeing. I affirm it to be a cat and deny it is a dog. If the pet is really a cat and not a dog, then my double assertion (affirmation and denial) contains truth; but if it is really a dog and not a cat, then I am mistaken, and my double assertion contains error.

Merely looking at the pet and forming an idea of it is not knowledge that can be true or false. I must apply an idea to the pet and mentally assert (affirm or deny) something about this pet in a judgment. Then the judgment/knowledge automatically becomes true or false, depending on whether or not the judgment and assertion corresponds to the reality itself.

Truth and error are always found in the judgment. This is called mental or logical truth. It consists of the conformity of the mind to the thing. Logical error is defined as a disconformity of the mind to the thing.

There is also truth in the things. We have, for example, a very definite idea of the pet called a cat. The idea of cat involves a number of subordinate ideas regarding body structure, appearance, and so forth. This idea is a norm or standard to which a pet must conform in order to be designated as a cat. If the pet agrees with this standard, it is a cat, otherwise it is not.

When objects conform to a recognized mental norm or standard, they are said to possess truth of being or ontological truth. Ontological truth is defined as the conformity of a thing to the mind. Reversely, ontological error is the disconformity of a thing to the mind.

Now that all this is understood, we can define truth in general. It is the conformity between mind and thing. Conversely, error in general is the disconformity between mind and thing.


Man is certain that he possesses knowledge about many things. He is equally certain that there are far more things of which he is totally ignorant. All of us are conscious of the fact that we have made many errors in the past and that much of our present knowledge may be erroneous. The consciousness of all this is reflected in his mental attitude toward things he knows or thinks he knows.

Doubt is that state of mind in which a suspended judgment is made because of the mind’s inability to decide whether the judgment is true or false. If the mind can discover no reasons, or practically no reasons, which enable it to come to a decision regarding the truth or error of its judgment, then we have a doubt that is negative. If the mind has discovered reasons, but they are of practically equal weight for and against the truth of the judgment, then we have a doubt that is positive. In both cases the result is the same, the fear of error cannot be overcome, and judgment remains suspended. There are innumerable instances where a person cannot overcome his doubts. And this is perfectly acceptable.


Opinion is a state of mind in which it decides for the truth of a judgment but with fear of the possibility of error. The best we can attain with regard to the truth of the judgment is a certain degree of probability. The reasons are good on both sides of the question. The mind realizes, however, that reasons for making the decision are weighty enough to justify adherence to one side of the question rather than to the other. The mind is hindered from giving an unqualified assent to the judgment, because of fear of error, and there is still lack of certitude. And this is perfectly acceptable.

Both in doubts and opinions there is lack of certitude. In the case of doubts a person can come to no decision. In the case of opinions a person can make a decision. But in both cases, however, the fear of the possibility of error cannot be overcome and the mind is in a condition of hesitancy and uneasiness. The mind will remain in this attitude as long as a prudent fear of error continues. As soon as the fear of error is definitely overcome, hesitancy and uneasiness vanish, and the mind rests in a state of certitude.


Certitude is a state of the mind in which it gives a firm assent to a judgment, without fear of the possibility of error, because of recognized valid reasons.

Three elements enter into the concept of certitude:

  • (1) a firm assent to the judgment,
  • (2) the absence of fear of possible error, and
  • (3) the understanding of the valid reasons which exclude this fear.

Now it needs to be realized that this does not mean that the mind is really infallible in these judgments and that error is impossible. What it does mean is that the mind is subjectively certain of its grounds and does not fear the possibility of error. It is convinced that it is in possession of knowledge which is true and valid.


The Motive of Certitude

The motive of certitude, which influences the mind in giving a firm assent to a judgment, has differences in value, and this produces increasing degrees of certitude. A person is not equally certain of all truths even though all these truths are certain to his mind. For instance, I am sure beyond doubt that the planet Pluto exists even though I have never directly seen it. I am more sure about the existence of Earth, however, because I live here. There are three degrees of certitude.

Moral Certitude

Moral certitude is based upon a moral (don’t confuse this with “ethical”) law, upon the customary natural conduct of human beings in a given environment and under given conditions. It has been observed that men under such circumstances act and react uniformly in the same way. For example, the judgment that “a nation whose citizenry lives in reasonable comfort is not prone to revolution” is a truth which is morally certain. There may be individual cases where this judgment may be mistaken but we feel certain that the law, generally speaking, expresses a truth.

Physical Certitude

Physical certitude is certitude based upon a physical law of nature and this law is considered to be uniform, necessary and universal. Exceptions to such a law are impossible in the natural order of things. An example would be the judgment that water will freeze at 32 degrees at sea level. In this case we are physically certain that the judgment is true.

Metaphysical Certitude

Metaphysical certitude is certitude based upon a metaphysical law, an exception to which is intrinsically impossible because it would involve a contradiction in itself. For example, “a circle is no square” is metaphysically certain. So is “the part is smaller than the whole.”

A glance at the truths contained in the judgments expressing these three classes of truths will show us that are increasing degrees in our certitude regarding them. Moral certitude does not give us the firmness of assent which we possess with respect to physical certitude. Metaphysical certitude is far superior to that given by moral and physical certitude.

These ideas are basic and they lie at the very root of knowledge. A proper understanding of them will assist a person materially in preparing to meet the problem of knowledge in an intelligent manner. When applied in specific cases of argument, as will be seen later, a person who has a firm understanding of these basics has an advantage over someone who does not.

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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.

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