Knowledge is what is known as opposed to what is not known to a human being. It is the product of thinking or thought, which usually employs or works with concepts, like truth, belief, and wisdom. The definition of knowledge should comply with the prerequisites of a definition and should reflect the nature (or further specifics or descriptors) of knowledge. Therefore the best way to define knowledge is to take an analogy, and use it as a model for defining knowledge. Knowledge is said to be acquired, or created through familiarization, hence what is known is then familiar to us.
Familiarity breeds through differentiation and sophistication, and typically works with smaller groups of people who share the same social experience, consisting mostly of the skills and competences of a trade or a profession, and a common language, meaning a vocabulary and the pragmatics of the same, the two basic factors related and associated in defining knowledge. Knowledge is essentially the consciousness of an object, i. e. of any thing, fact, or principle belonging to the physical, mental, or metaphysical order, that may in any manner be reached by cognitive faculties.
An event, a material substance, a man, a geometrical theorem, a mental process, the immortality of the soul, the existence and nature of God, may be so many objects of knowledge. Thus knowledge implies the antithesis of a knowing subject and a known object. It always possesses an objective character and any process that may be conceived as merely subjective is not a cognitive process. Any attempt to reduce the object to a purely subjective experience could result only in destroying the fact itself of knowledge, which implies the object, or not-self, as clearly as it does the subject, or self.
Truth and certitude are conditions of knowledge. A man may mistake error for truth and give his unreserved assent to a false statement. He may then be under the irresistible illusion that he knows, and subjectively the process is the same as that of knowledge; but an essential condition is lacking, namely, conformity of thought with reality, so that there we have only the appearance of knowledge. On the other hand, as long as any serious doubt remains in his mind, a man cannot say that he knows. “I think so” is far from meaning “I know it is so”; knowledge is not mere opinion or probable assent.
The distinction between knowledge and belief is more difficult to draw, owing chiefly to the vague meaning of the latter term. Sometimes belief refers to assent without certitude, and denotes the attitude of the mind especially in regard to matters that are not governed by strict and uniform laws like those of the physical world, but depend on many complex factors and circumstances, as happens in human affairs. I know that water will freeze when it reaches a certain temperature; I believe that a man is fit for a certain office, or that the reforms endorsed by one political party will be more beneficial than those advocated by another.
Sometimes, also, both belief and knowledge imply certitude, and denote states of mental assurance of the truth. But in belief the evidence is more obscure and indistinct than in knowledge, either because the grounds on which the assent rests are not so clear, or because the evidence is not personal, but based on the testimony ofwitnesses, or again because, in addition to the objective evidence which draws the assent, there are subjective conditions that predispose to it. Belief seems to depend on a great many influences, emotions, interests, surroundings, etc. , besides the convincing reasons for which assent is given to truth.
Faith is based on the testimony of someone else–God or man according as we speak of Divine or of human faith. If the authority on which it rests has all the required guarantees, faith gives the certitude of the fact, the knowledge that it is true; but, of itself, it does not give the intrinsic evidence why it is so. Knowledge supposes a judgment, explicit or implicit. Apprehension, that is, the mental conception of a simple present object, is generally numbered among the cognitive processes, yet, of itself, it is not in the strict sense knowledge, but only its starting-point.
Properly speaking, we know only when we compare, identify, discriminate, connect; and these processes, equivalent to judgments, are found implicitly even in ordinary sense-perception. A few judgments are reached immediately, but by far the greater number require patient investigation. The mind is not merely passive in knowing, not a mirror or sensitized plate, in which objects picture themselves; it is also active in looking for conditions and causes, and in building up science out of the materials which it receives from experience. Thus observation and thought are two essential factors in knowledge.