The actual character of this music we must gather from the writings about it, rather than the few fragments at hand for analysis. Just as music, because of its moral significance, became the subject of philosophic speculation, so did its scientific side appeal to the analytic mind of the Greeks, and their mathematicians and scientists in general expatiated at length upon its theory. From their writings we adduce first of all the fact that Greek music lacked at least one of the important elements of modern music, namely, polyphony--or harmony--the quality which of all, from a modern point of view, appeals most directly to our emotions, to our susceptibility, which is most closely associated with color and 'mood.’ Investigators, such as Westphal, Gevaert, etc., have untiringly striven to establish evidence of something more than simple homophony in the music of antiquity, but beyond a slight deviation in the instrumental accompaniments, partaking of the nature of grace notes, they have discovered traces of nothing but melody at the unison--or at the distance of an octave, when men and boys (or women) sang together, or when the voice was accompanied by an instrument of higher or lower pitch. Such and nothing more is the import of the testimony of Aristotle, when he says: 'Why is symphonous or antiphonal singing more pleasing than harmony? Is it not because it is the consonance of the octave? For antiphony is born of the voices of young boys and men, whose tones are equal in distance from each other as is the highest note of an octave from the lowest’ (Problems xix, 29). Curious as it may seem that it should never have occurred to a people intellectually so advanced to venture experiments in the field of polyphony; that it should never have entered their minds to strike two strings of the lyre or kithara simultaneously, or that an occasional false note struck along with the right one should not have suggested the possibilities of the 'third dimension’ in music, it remains a fact that in all the mass of theoretical and technical writings upon the art sufficient to reconstruct the entire 'system’ of Greek music, no mention is made of harmony or polyphony.[35] We can only conclude then that combinations other than the perfect consonance of the octave, all mixtures of sounds or a confusion of lines, were hostile to the Greek ideal of purity, to the underlying principle of classic simplicity.