William says: "Plato applied and adapted numbers to the form of that soul, and he stated that they enter, as it were, into its composition from the very fabric of the world, for which he held such a soul, as he is seen to have admitted. For he held that the distances that stretch from the earth up to the ninth, in fact, up to eighth heaven, according to him, are proportional to the numbers that he put in its shape, and he held that the whole world and its parts are musical, according to what I could understand about him, naturally suited and connected to one another in harmonious proportions and, for this reason, the soul of the world itself, which necessarily had to harmonize with and fit its body, was naturally united and somehow composed by similar connections, as I touched upon for you above when I spoke about the same and the other of it."

Original Latin

The World Soul

The great Greek philosopher, Plato (428/427–348/347 BC) held that the whole world had a soul, just as each living being in the world did. He argued that musical harmony had power over our souls, noting the strong influence of music upon our minds or souls and their moods, turning them with incredible speed from sorrow to joy and the other way around.

Note the many effects that William claimed music has on our emotions. Is this still true today with the music that you listen to?

Like likes and is like Like

Plato further believed that nothing is delighted except by that which is like it. Is this true? If I am delighted by great wine, does that mean that I must be like a great wine? He concluded that, because our souls take such delight in harmonies, our souls must be very much like harmonies and were in fact composed of musical harmonies. He also held the same thing about the soul of the world.

Thus there are two sorts of music in the world: that of our individual souls and that of the soul of the world. Philolaus , (circa 470–385 BC), another philosopher, held that the human soul was a harmony and that the soul of the world was as well.

Though it might sound like a neat idea, what happens to the immortality of the soul, which Plato certainly wanted to hold, if the soul is a harmony? Musical harmonies, after all, quickly fade away.

William vs. Plato

William gives several arguments against Plato’s view. The first argument is that similar things are actually distasteful and cause sorrow to our souls rather than pleasure. Give examples — either those that William gives or ones of your own.

The second argument is that our souls could, on Plato’s view, take delight only in things that have quantity and can be counted. So they would find no delight in the sciences, in the virtues, or in God their creator, whom, according to Christian belief, will be our source of delight for eternity.

William's third argument is that, since our souls seem to be harmonies and since they love music and make music, the soul of the world would — if it were possible — fill the heavens with the sounds of music. Hence, the ratios of the various planetary spheres would have to be in harmonious proportions, which William claims that they are not.

Aristotle gets the last word

Furthermore William points out that Aristotle showed that heaven cannot have any sounds or music. A sound, after all, is produced by a violent striking -- and violence can have no place in the heavens. Moreover, a sound is produced by the compression of air, and air is not found above the sphere of the moon. Recall the picture of the medieval universe with four elements in the sphere below the moon with the other spheres of the planets above the lunar sphere.

Because sound is produced when air is compressed, soft things cannot produce any sound. You can’t make noise by pounding on a pillow. Even the waves of the sea crashing upon the shore require air in order to make a sound.

Since the heavens have no sound, there would also be no musical harmony in the heavens. So if a soul were a harmony, it would be most unsuitably located in the heavens.