Since, therefore, the need to impart is of this primary and essential character, we ought not to look upon it as something separable from and additional to the need to think or to be; it is only by imparting that one is enabled to think or to be. Everyone, in proportion to his natural vigor, necessarily strives to communicate to others that part of his life which he is trying to unfold in himself. It is a matter of self-preservation, because without expression thought cannot live. Imaginary conversation—that is, conversation carried on without the stimulus of a visible and audible response—may satisfy the needs of the mind for a long time. There is, indeed, an advantage to a vigorously constructive and yet impressible imagination in restricting communication; because in this way ideas are enabled to have a clearer and more independent development than they could have if continually disturbed by criticism or opposition. Thus artists, men of letters, and productive minds of all sorts often find it better to keep their productions to themselves until they are fully matured. But, after all, the response must come sooner or later or thought itself will perish. The imagination, in time, loses the power to create an interlocutor who is not corroborated by any fresh experience. If the artist finds no appreciator for his book or picture he will scarcely be able to produce another. People differ much in the vividness of their imaginative sociability. The more simple, concrete, dramatic, their habit of mind is, the more their thinking is carried on in terms of actual conversation with a visible and audible interlocutor. Women, as a rule, probably do this more vividly than men, the unlettered more vividly than those trained to abstract thought, and the sort of people we call emotional more vividly than the impassive. Moreover, the interlocutor is a very mutable person, and is likely to resemble the last strong character we have been in contact with. I have noticed, for instance, that when I take up a book after a person of decided and interesting character has been talking with me I am likely to hear the words of the book in his voice. The same is true of opinions, moral standards, and the like, as well as of physical traits. In short, the interlocutor, who is half of all thought and life, is drawn from the accessible environment.