The original meaning of li (理) was the texture of jade; later it was extended

to contain three meanings: 1) the physical forms or proprieties of things, such

as length, size, shape, tensile strength, weight, and color; 2) the universal laws

followed by all things and beings; and 3) the original source or ontological

existence of things. The last two meanings are similar to those of Dao. Scholars

of the Song and Ming dynasties were particularly interested in describing and

explaining the philosophy known as li (理), and considered it as the highest

realm, giving rise to the School of Principle which dominated academic thought

in the period from the Song to the Ming dynasties.