It answers the questions "What is beauty?" and "What is the essence of beautiful things?" and "What is art?" and "What is the essence of art?"
It suggests three types of world: World of Being, World of Becoming, and World of Art
World of Being

The reality, unchanging and eternal, the universal form of any idea in metaphysical form, the idea of beauty
World of Becoming

The appearance, the changing, and temporal world, the appearance of the reality and where beautiful things exist
World of Art

The imitation or illusion of what is seen from the physical thing
Pythagoras

Cosmological theory of music - the sound of the universe is the sound of music
Plato

Epistemological theory of music - music is for the soul, gymnastics is for the body
Augustine

Theological theory of music - singing is praying twice over
Representationism

Art is an image, an appearance, a copy, or a reproduction of things, people, objects, or events
Ways of Representing Nature
Physical Alteration - changing the physical appearance of nature
Selective Modification - enhancing the appearance of nature
Perceptual Interpretation - copying nature according to the choice of the artist
Formalism

Art is the combination of perceptual elements, art is non-figurative because it does not contain any representation
Formalist Theory of Art

Art is born from the inner necessity of the artist in an enigmatic, mystical way through which it acquires an autonomous life and becomes an independent subject, animated by a spiritual breath
Kandinsky's categories of paintings: Impressions, Improvisations, Compositions
Expressionism

The transfer of the artist's expression of emotions and ideas into an art
Periods of Classical Music
Baroque
Classical
Romantic
Aesthetic Hedonism

Beauty is pleasure, ugly is pain
Aesthetic Functionalism

The person's feeling of need of an object which satisfies their needs, form follows function
Action Theory of Art
Style of abstract expressionism by Jackson Pollock, the process of putting, dripping, pouring, and splashing paints on the canvas
Institutional Theory of Art
Art is an institution in society, the artworld (artists, critics, historians, patrons, museums, etc.) determines what is considered art
For something to become art, it must pass all the standards set by the artworld institution