As definition sets forth intension, so division (or the reverse process, classification) expounds extension. Intension and extension, definition and division, are clearly correlative; in language previously used, _intension_ is meaning as a principle of identifying particulars; extension is the group of particulars identified and distinguished. Meaning, as extension, would be wholly in the air or unreal, did it not point to some object or group of objects; while objects would be as isolated and independent intellectually as they seem to be spatially, were they not bound into groups or classes on the basis of characteristic meanings which they constantly suggest and exemplify. Taken together, definition and division put us in possession of individualized or definite meanings and indicate to what group of objects meanings refer. They typify the fixation and the organization of meanings. In the degree in which the meanings of any set of experiences are so cleared up as to serve as principles for grouping those experiences in relation to one another, that set of particulars becomes a science; _i.e._ definition and classification are the marks of a science, as distinct from both unrelated heaps of miscellaneous information and from the habits that introduce coherence into our experience without our being aware of their operation. Definitions are of three types, _denotative_, _expository_, _scientific_. Of these, the first and third are logically important, while the expository type is socially and pedagogically important as an intervening step. [Sidenote: We define by picking out] I. Denotative. A blind man can never have an adequate understanding of the meaning of _color_ and _red_; a seeing person can acquire the knowledge only by having certain things designated in such a way as to fix attention upon some of their qualities. This method of delimiting a meaning by calling out a certain attitude toward objects may be called _denotative_ or _indicative_. It is required for all sense qualities--sounds, tastes, colors--and equally for all emotional and moral qualities. The meanings of _honesty_, _sympathy_, _hatred_, _fear_, must be grasped by having them presented in an individual's first-hand experience. The reaction of educational reformers against linguistic and bookish training has always taken the form of demanding recourse to personal experience. However advanced the person is in knowledge and in scientific training, understanding of a new subject, or a new aspect of an old subject, must always be through these acts of experiencing directly the existence or quality in question. [Sidenote: and also by combining what is already more definite,]