I have shown elsewhere[25] that the musical scale is simply a species of space--a space, however, of only one dimension, and that, a one-sided one. If, now, a person who could only hear, should attempt to develop a conception of the world in this, his linear space, he would become involved in many difficulties, as his space would be incompetent to comprehend the many sides of the relations of reality. But is it any more justifiable for us, to attempt to force the whole world into the space of our eye, in aspects in which it is not accessible to the eye? Yet this is the dilemma of all molecular theories. We possess, however, a sense, which, with respect to the scope of the relations which it can comprehend, is richer than any other. It is our reason. This stands above the senses. It alone is competent to found a permanent and sufficient view of the world. The mechanical conception of the world has performed wonders since Galileo's time. But it must now yield to a broader view of things. A further development of this idea is beyond the limits of my present purpose. One more point and I have done. The advice of our philosopher to restrict ourselves to what is near at hand and useful in our researches, which finds a kind of exemplification in the present cry of inquirers for limitation and division of labor, must not be too slavishly followed. In the seclusion of our closets, we often rack our brains in vain to fulfil a work, the means of accomplishing which lies before our very doors. If the inquirer must be perforce a shoemaker, tapping constantly at his last, it may perhaps be permitted him to be a shoemaker of the type of Hans Sachs, who did not deem it beneath him to take a look now and then at his neighbor's work and to comment on the latter's doings. Let this be my apology, therefore, if I have forsaken for a moment to-day the last of my specialty. FOOTNOTES: [Footnote 19: Delivered before the German Casino of Prague, in the winter of 1871. A fuller treatment of the problems of this lecture will be found in my _Contributions to the Analysis of the Sensations_ (Jena, 1886), English Translation, Chicago, 1895. J. P. Soret, _Sur la perception du beau_ (Geneva, 1892), also regards repetition as a principle of æsthetics. His discussions of the _æsthetical_ side of the subject are much more detailed than mine. But with respect to the psychological and physiological foundation of the principle, I am convinced that the _Contributions to the Analysis of the Sensations_ go deeper.--MACH (1894).] [Footnote 20: Kant, in his _Prolegomena zu jeder künftigen Metaphysik_, also refers to this fact, but for a different purpose.] [Footnote 21: Compare Mach, _Fichte's Zeitschrift für Philosophie_, 1864, p. 1.]