Yet a purely objective method will not suffice to give us an adequate idea of beauty. For beautiful things are created by men, not passively discovered, and are made, like other things which men make, in order to realize a purpose. Just as a saw is a good saw only when it fulfills the purpose of cutting wood, so works of art are beautiful only because they embody a certain purpose. The beautiful things which we study by the objective method are selected by us from among countless other objects and called beautiful because they have a value for us, without a feeling for which we should not know them to be beautiful at all. They are not, like sun and moon, independent of mind and will and capable of being understood in complete isolation from man. No world of beauty exists apart from a purpose that finds realization there. We are, to be sure, not always aware of the existence of this purpose when we enjoy a picture or a poem or a bit of landscape; yet it is present none the less. The child is equally unaware of the purpose of the food which pleases him, yet the purpose is the ground of his pleasure; and we can understand his hunger only through a knowledge of it. The dependence of beauty upon a relation to purpose is clear from the fact that in our feelings and judgments about art we not only change and disagree, but correct ourselves and each other. The history of taste, both in the individual and the race, is not a mere process, but a progress, an evolution. "We were wrong in calling that poem beautiful," we say; "you are mistaken in thinking that picture a good one"; "the eighteenth century held a false view of the nature of poetry"; "the English Pre-Raphaelites confused the functions of poetry and painting"; "to-day we understand what the truly pictorial is better than Giotto did"; and so on. Now nothing can be of worth to us, one thing cannot be better than another, nor can we be mistaken as to its value except with reference to some purpose which it fulfills or does not fulfill. There is no growth or evolution apart from a purpose in terms of which we can read the direction of change as forward rather than backward.