The Expression Theory posits that the primary purpose of music is to express the composer's emotions and ideas, rather than to serve any other purpose.

Plato believed that music has the power to purify the soul and elevate the mind, and that it can be used to promote moral and intellectual development.

The Aesthetic Theory of music holds that the value of music lies in its beauty and its ability to evoke aesthetic experiences.

Schopenhauer believed that music has the unique ability to express emotions and ideas that cannot be conveyed through language.

The Functional Theory of music posits that the value of music lies in its ability to serve a specific function, such as promoting social cohesion, enhancing religious rituals, or providing entertainment.

Hegel believed that music has the unique ability to reveal the essence of reality and to provide a glimpse into the underlying structure of the universe.

The Cognitive Theory of music posits that the value of music lies in its ability to enhance cognitive abilities, such as memory, attention, and problem-solving.

Nietzsche believed that music has the power to subvert traditional values and norms, and to challenge established social and political structures.

The Social Theory of music posits that the value of music lies in its ability to promote social cohesion and to foster a sense of community.

Deleuze believed that music has the unique ability to create new worlds and realities, and to challenge and subvert existing social and political structures.

The Political Theory of music posits that the value of music lies in its ability to be used to promote political change and to challenge existing social and political structures.

Adorno believed that music has the unique ability to resist commodification and commercialization, and to maintain its integrity and autonomy as an art form.

The Economic Theory of music posits that the value of music lies in its ability to generate economic value, such as through sales, royalties, and licensing fees.

Gadamer believed that music has the unique ability to transcend cultural and historical boundaries, and to communicate across different cultures and time periods.

The Environmental Theory of music posits that the value of music lies in its ability to promote environmental awareness and conservation, and to inspire people to take action to protect the environment.