Pythagoras believed that the universe is governed by mathematical principles, and that the Harmonic Series, a sequence of frequencies that produce harmonious intervals, is the basis for the harmony of the cosmos.

Plato believed that music, like other forms of art, is an imitation or representation of the eternal and unchanging Forms that exist in the realm of the divine.

'Musica universalis' is the idea that the universe itself is a musical composition, with its own inherent harmonies and rhythms.

Plato believed that music has a profound impact on human behavior and can be used to shape character, promote social harmony, and inspire moral virtue.

Aristotle believed that the primary purpose of music is to provide pleasure and enjoyment, and that it has the ability to elevate the soul and bring about a state of catharsis.

Absolute music is music that stands on its own, without any external references or associations, and is appreciated for its own inherent musical qualities.

The Romantic movement in music was characterized by a focus on individual expression, emotion, and the exploration of new musical possibilities, breaking away from the more structured and formal approach of the Classical period.

Arthur Schopenhauer believed that music has a unique ability to transcend the limitations of language and reveal the underlying essence of the world, providing a glimpse into the true nature of reality.

Aleatoric music is music that incorporates elements of chance and indeterminacy, allowing for unpredictable and unique outcomes in the performance.

Gesamtkunstwerk, meaning 'total work of art', is a concept that seeks to combine different art forms, such as music, drama, and visual arts, into a single cohesive and immersive experience.

Friedrich Nietzsche believed that music has the power to reveal profound truths about the human condition and can lead to a deeper understanding of oneself and the world.

Musical ontology delves into the philosophical questions surrounding the nature of music, its existence, and its relationship to the broader fabric of reality.

Sonic art is a genre of contemporary music that focuses on the exploration of sound as a medium, often in relation to space and the environment.

Musical relativism is the idea that musical preferences, values, and meanings are shaped by cultural and historical factors, rather than being absolute or universal.

Musical hermeneutics is the branch of philosophy that deals with the interpretation of musical works and performances, exploring their meaning and significance.