  There are certain problems with this series of definitions, read as an apriori reconstruction of the categories. In particular, the definitions of ‘substance’ and ‘quality’ seem to be jointly circular, unless we take as already given universals such as substance-hood, which make the definitions somewhat vacuous. I will give another reconstruction, one which roughly follows the great Nyāya-Vaiśeṣika author Udayana (cf. Tachikawa 1981).