THE NEED OF A PURPOSE.--Nor are we to forget that we cannot intelligently erect our building until we know the _purpose_ for which it is to be used. No matter how much building material we may have on hand, nor how skillful an architect we may be, unless our plans are guided by some definite aim, we shall be likely to end with a structure that is fanciful and useless. Likewise with our thought structure. Unless our imagination is guided by some aim or purpose, we are in danger of drifting into mere daydreams which not only are useless in furnishing ideals for the guidance of our lives, but often become positively harmful when grown into a habit. The habit of daydreaming is hard to break, and, continuing, holds our thought in thrall and makes it unwilling to deal with the plain, homely things of everyday life. Who has not had the experience of an hour or a day spent in a fairyland of dreams, and awakened at the end to find himself rather dissatisfied with the prosaic round of duties which confronted him! I do not mean to say that we should _never_ dream; but I know of no more pernicious mental habit than that of daydreaming carried to excess, for it ends in our following every will-o'-the-wisp of fancy, and places us at the mercy of every chance suggestion. 3. TYPES OF IMAGINATION Although imagination enters every field of human experience, and busies itself with every line of human interest, yet all its activities can be classed under two different types. These are (1) _reproductive_, and (2) _creative_ imagination. REPRODUCTIVE IMAGINATION.--Reproductive imagination is the type we use when we seek to reproduce in our minds the pictures described by others, or pictures from our own past experience which lack the completeness and fidelity to make them true memory. The narration or description of the story book, the history or geography text; the tale of adventure recounted by traveler or hunter; the account of a new machine or other invention; fairy tales and myths--these or any other matter that may be put into words capable of suggesting images to us are the field for reproductive imagination. In this use of the imagination our business is to follow and not lead, to copy and not create. CREATIVE IMAGINATION.--But we must have leaders, originators--else we should but imitate each other and the world would be at a standstill. Indeed, every person, no matter how humble his station or how humdrum his life, should be in some degree capable of initiative and originality. Such ability depends in no small measure on the power to use creative imagination.