Musical aesthetics is admitted to be a peculiarly occult branch of philosophy, and one in which little progress has been made. Prominent thinkers have wrestled with it without conclusive result. Among scientists and philosophers who have recently attacked it are Bain, Helmholtz, Darwin, Weissmann, and Herbert Spencer; and although their respective views remain authoritative utterances on the subject they still fail (probably because none of these thinkers gave more than a fraction of his attention to the problem) to supply a complete and convincing rationale of musical influence. The thinker on music perceives at the outset the distinction that music does not draw its general form from nature like painting and sculpture do, or from language like poetry does, but that this general form has been shaped gradually by man.