characteristic they have in common. The next stage is when he learns from his elders to call that particular kind of
object (that particular class of objects) by the word "chair." Now, he has a much firmer form of retaining in his
mind that awareness which previously he could capture only as an image. The final step takes place when and if he
learns the definition of "chair." A definition expresses, explicitly and in words, the essential characteristic(s) of a
number of existents, in virtue of which characteristic(s) those existents are differentiated from all other existents
and united into a single class.
Although the concept involved is a very simple one, we may observe in the above example the essence of the
process of concept-formation. It consists of the mental act of classifying a number of existents on the basis of a
characteristic(s)—an attribute(s)—which is exhibited by those existents and which differentiates them from all
other existents. (An "attribute" is an aspect of an entity which can be isolated conceptually for the purpose of
identification, but which cannot exist independently of the entity—for example, shape, color, length, weight.) In
this particular example, the concept was initially symbolized by means of a visual image; but this is not an essential
of the concept-formation process; it occurs most frequently in children (and in the mind of primitive men). Most
concepts are acquired directly in the form of words, without the intermediary stage of an image or other
nonlinguistic symbol.
Concept-formation moves from the apprehension of similarities and differences among existents (entities,
attributes, actions, relationships) to an explicit identification of the nature of those similarities and differences.
Concept-formation involves a process of discrimination and integration. Discrimination entails the mind's power of
abstraction, which is the ability to isolate, to distinguish and consider separately, a particular aspect or character of
an existent. Integration entails the mind's ability to retain a number of instances of such abstracted concretes, to
relate them, to unify them into a single awareness which is represented in consciousness by means of a symbol.
This unification, as we have seen, occurs on a primitive level by means of a non-linguistic symbol. On a mature
level, as a fully realized concept, it is achieved by means of a precisely defined word.