Kanada is the founder of the Vaiśeṣika School (one of the six Hindu schools of philosophy). His exact dates are unknown, but it is believed that he composed the Vaiśeṣika Sutra around the third century BC. His focus was on the nature of reality, which he understood as dharma. In the Vedic tradition, the word “dharma” stands for the cosmic order as a whole. All that is there in the universe is part of dharma. When there is a breakdown of the cosmic order, then there is “adharma,” which is a negation of dharma.
The Vaiśeṣika Sutra opens with these lines:
"We shall now consider the nature of dharma.
It is from dharma that the highest and supreme good is achieved.
The Veda has its authority because of its concern with dharma."
The system that Kanada elucidates in his Vaiśeṣika Sutra is pluralistic realism (a doctrine of multiplicity). He is concerned with the independent reality of things, outside and independent of the observer. He classifies the fundamental constituents of reality into seven categories: substance, quality, action, universality, particularity, a relation of inherence, and absence or negation.
“Substance” is the most important category since other categories can get manifested only in relation to substance. Kanada divides the category “substance” into nine types of atoms: earth, water, fire, air, ether, space, time, self, and mind. The objects in the visible universe are composed of earth, water, fire, and air atoms in association with (as per the requirement) other atoms. Ether, space, time, and self are eternal and all-pervading. Mind is of an atomic size and it functions in conjunction with the self atoms which fuel life—every human being has one self atom and one mind atom.
Kanada talks about twenty-four kinds of qualities and five kinds of actions that are inherent in substances. The occurrence of an object is an example of the universality of substance. The category of “absence” is an explanation for all kinds of negation or non-existence in the fabric of reality.