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.