...“formalism” in the philosophy of art — the idea that we can explain why something is beautiful by pointing out the formal parts that make it up.
Some aestheticians do not think you can “reduce” art to its composite parts. They think beauty is beauty entirely because it is irreducibly subjective — a pleasurable phenomenon that walks the line between emotion and mysticism.
Formalism holds that we can account for aesthetic judgments in non-aesthetic terms. Maybe we find a song beautiful because of its tertian harmonies, or we like a certain photo because the angular lines converge on a point. Formalism “unweaves the rainbow” by telling you exactly why you find something beautiful.
Formalism is the idea that beauty in art can be explained through its formal, mathematical structures rather than subjective experience.