Cosmic Harmony and Kepler's Mathematical Universe

gravity that represents its expression. We will see how in subsequent speculation, particularly with Fludd, attention will be placed on the correspondence between musical notes, states of the soul, consciousness, and points of the body.

Therefore, a fundamental point: Classical harmony is regulated by the first 4 numbers: $1, 2, 3, 4$ which can be seen as the tetraktys. When one wants to develop the musical scale more thoroughly, other notes with other intervals are also inserted, but for what we need for the moment, this is sufficient.

The Cosmic Solids and the Creation of the World

25.2 Hermeticism, Neoplatonism and Harmony of the Spheres

So the Pythagoreans, later taken up by Plato, had defined a true mathematics of harmony, an objective science of harmony that defined what was beautiful and harmonic in contrast to what was random and disharmonic.

It is important to understand therefore that in this context harmony is no longer just a set of consonant notes, but harmony is an idea: the visible or intelligible manifestation of an archetypal order of Divine Being through a Universal Hierarchy.

Visual harmony is equal and governed by the same laws as auditory harmony, which is why these proportions are used, for example, in the construction of Gothic temples that are structured following this aesthetic approach.

Harmony therefore is the visible manifestation of an archetypal order that reveals Divine Being. In this context, the most important harmony is the celestial Harmony of the planets and the Cosmos that are structured according to archetypal proportions:

Moreover, knowing music is nothing other than knowing the order of all things and the divine design that has so ordered them; the order indeed, in which all individual things have been united in a single whole by the intelligence of a creator, will produce a kind of sweetest and true harmony of divine music.
Hermes Trismegistus, Asclepius, 13

This is the starting point that moves Kepler in his investigations of the cosmos. Boethius medieval speculation is indebted to him in this aspect, Pythagorean traditions etc... Zorzi De Harmonia Mundo influences Fludd more than Kepler Agrippa on the Harmony of the Spheres

In the Renaissance era, the correspondence between planets, musical notes and musical modes was widespread. It was a typically Neoplatonic theme born from speculations originating from the Timaeus, mixed with natural magic

25.3 Kepler and the structure of the Cosmos

Harmony and Geometry

Kepler's Heliocentrism

Already Copernicus at the end of De Revolutionibus considered aesthetics and theology as one of the main motors that should have pushed to accept his own system:

"Who in this most beautiful temple, could place this lamp in a different or better place than that from which it can illuminate everything together? [...It is] an admirable symmetry of the world and a precise harmonic relationship between movement and the size of the spheres, which cannot be found in any other way"
Copernicus De Revolutionibus

Universal Harmony is expressed by the celestial spheres because the Heavens sing the Glory of God. Therefore - says Kepler - All investigations of the external world should lead to discovering the order and harmony imposed by God

"Astronomers are priests of the Most High God in relation to the Book of Nature (ex parte librij Naturae), so it is our duty not to seek our glory, but the glory of God above all other things"

Therefore Kepler begins in 1596 the investigation of universal harmony based mainly on Geometry. Geometry indeed allows to highlight the hidden structure of things and grasp the order, that is, the harmony they have.

Kepler embraces the Copernican theory because, he says in Dissertatio cum Nuncio Sidereus: "The Sun in truth is at the center of the cosmos, is the heart of the cosmos, the source of light, the source of heat, the origin of life and the movement of the world"

The planets orbit around the sun because the Sun is the symbol of God, the planets on the other hand are the beneficial mediators, the angels that spreading the glory of the creator in the Universe influence and illuminate the souls of men.