Triadic Insights in Astronomy, Art and Music

Abstract

Three huge discoveries during the Renaissance transformed all of science and art: they were the invention of musical harmony, the discovery of linear perspective, and the realization of the heliocentric structure of the solar system. These seemingly unrelated developments have a common basis in cognitive psychology. All three involve an understanding of the relationships among three sensory "cues." The astronomical insight was essentially an understanding of the meaning of shadows: a light source (the sun), an object (the moon), and its shadow (the phases of the moon as seen from the earth). A similar shadow-related insight led to the geometrically correct depiction of light and shadows in Renaissance paintings and eventually to the laws of linear perspective (not deducible from the relative size of two objects, but deducible from the relative sizes of three aligned objects). The three cues in music are the three tones that produce harmony -- the "tonality" that led to the major and minor modes of Renaissance music and still in use today. These (and other) forms of "triadic" sensory processing are not undertaken by infra-human animal species, but they lie at the heart of the unusual cognitive capabilities of the human mind.