Owing to its negative character, this criterion does not give us much information as to the real qualities of art. But even the poorest definition is enough to begin with, if it only holds good with regard to all particular cases. Unfortunately, however, we need only apply the test of independence in the concrete instance to find that even the applicability of this single accepted criterion may be seriously disputed. There is scarcely any author, however he may formulate his general definitions of art, who would assess the relative value of art-works according to their degrees of disinterestedness. No candid man would, for instance, nowadays contend that an arabesque composition is _per se_ more æsthetically pure than a statue or a poem.[11] But we may even go farther. We must question whether every work of art ought to be degraded from its æsthetic rank, if it can be convicted of having served any external utilitarian purpose. This strict conception of the æsthetic boundaries has been eloquently attacked by Guyau in his celebrated treatise, _Le principe de l’art et de la poésie_.[12] Though the ultimate conclusions of this work are perhaps not so clear as might be desired, yet we do not see how his attitude in estimating concrete manifestations of art can be assailed. It would, to take an example, be absurd to contend that the singing of Taillefer lost in æsthetic value by contributing to the victory of Hastings. And however strictly we may insist upon the requirement that every genuine work of art should have been created purely for its own sake, we cannot possibly conceal the fact that some of the world’s finest love lyrics were originally composed, not in æsthetic freedom, which is independent of all by-purposes, but with the express end of gaining the ear and the favour of a beloved woman. The influence which such foreign, non-æsthetic motives have exercised on art will also become more and more apparent with increased knowledge of the conditions of æsthetic production. The further the psychological biographer pushes his indiscreet researches into the private life of individual artists, the more often will he find that some form of interest—personal, political, ethical, religious—enters into the so-called disinterested æsthetic activity. Such instances must induce undogmatic authors to relax to some extent the strict application of this criterion. And even those philosophers who, in spite of the historical evidence, insist upon applying it will be compelled to admit that they have taken for works of genuine art productions which, from their philosophic standpoint, have no claim to the title.