Of the six classes of entities or categories (padartha) we have already given some account of dravya (1). Let us now turn to the others. Of the qualities (guna) the first one called rupa (colour) is that which can be apprehended by the eye alone and not by any other sense. The colours are white, blue, yellow, red, green, brown and variegated (citra). Colours are found only in kshiti, ap and tejas. The colours of ap and tejas are permanent (nitya), but the colour of kshiti changes when heat is applied, and this, Shridhara holds, is due to the fact that heat changes the atomic structure of kshiti (earth) and thus the old constitution of the substance being destroyed, its old colour is also destroyed, and a new one is generated. Rupa is the general name for the specific individual colours. There is the genus rupatva (colourness), and the rupa guna (quality) is that on which rests this genus; rupa is not itself a genus and can be apprehended by the eye. Read more »
akasha, atomic structure, guna, katu, natural taste, nitya, rasa, rupa, tejas, vayu
