The Pythagoreans believed that number is the origin of all things, that the nature of things is determined by a certain quantitative relationship, and that all things constitute a harmonious order according to a certain quantitative ratio; thus they proposed The view of "beauty is harmony" believes that the harmony of music is composed of tones of different heights, lengths, and weights according to a certain quantitative ratio. "Music is the harmonious unity of opposing factors, which leads to unity from variety and leads to harmony from disharmony." "This is the bud of the dialectical thought of ancient Greek art, and also contains the universal principle of "integration and change" in art.

The Pythagoreans believed that the order of movement of celestial bodies was also a kind of harmony. Each planet maintained a harmonious distance, moved along its own orbit at a strictly fixed speed, and produced various harmonious tones. and melody, the so-called "music of the heavens" or "music of the heavens." The Pythagoreans also believed that the external harmony of art is consistent with the internal harmony of the human soul, resulting in the so-called "sound response". They believed that music generally has two styles, hard and soft, which can cultivate and influence people's character and emotions. Change, emphasizing the "purifying" effect of music. The Pythagoreans focused on the study of beautiful forms and believed that the most beautiful of all plane shapes is the circle, and the most beautiful of all three-dimensional circles is the sphere. It is said that the Pythagoreans were the first to discover the so-called "golden section" law and obtain the law of formal beauty about proportion. The aesthetic view of the Pythagoreans was objective idealism and had a profound influence on Plato, Neoplatonism and Renaissance artists.