Karma or activity has a special sense in Vaisheshika philosophy, meaning ‘motion’. In Vaisheshika Sutra, it is defined as that which inheres in one substance only, does not possess quality, and is an independent cause of conjunctions and disjunctions. There are five kinds of activity – throwing upwards, throwing downwards, contraction, expansion and locomotion (gamana).
Activity appears in corporeal or finite substances only; it does not appear in time, space, ether, and spirit, or in quality and activity. There can be no activity of an all-pervading thing because a change in its position is logically impossible. The quality and activity are ruled out as the substrata of activity for maintaining consistency with the definitions of quality and activity. Quality and activity both inhere in substances. So it follows that activity can appear neither in quality nor in activity.
Sometimes activities like throwing upwards, etc., may be the joint effect of gravity, effort and conjunction. For instance, when a person throws a stone upwards, the stone existing in the hand is the instrumental cause; conjunction with the spirit exercising effort or volition is the non-material cause; and the throwing out of the hand is the non-material cause of the throwing upwards of the stone.
Kanada, in Vaisheshika Sutra, declares that an activity is opposed to its effect. The reason is that an activity is subject to destruction, wrought by its effect, which consists of a subsequent conjunction. For example, when one moves his hand in order to hold the glass, the movement or activity inhering in the hand ceases as soon as the conjunction between the hand and the glass takes place. According to Kanada, the activity cannot be a cause of substances and further activities; although substances originate other substances and qualities other qualities. Such are the very searching assertions of Kanada, which need a rigorous conceptual analysis for their deeper understanding.
Activities may be volitional or non-volitional. According to Kanada, in a case of voluntary muscular activity the efficient cause is conjunction with spirit possessing volition or effort, a quality which is perceptible by the internal sense organ. But, in the case of the sudden upward motion produced in the pestle (musala) when struck by the mortar, there is conjunction of the hand with the rising pestle. However, the conjunction of the hand with the rising pestle possesses no causality, since the volition is absent. The impact of the mortar only is the non-material cause. In the absence of conjunction, gravity may also cause the precipitation of something, as in the case of rain. Fluidity causes the flowing of waters on the surface of the earth. Therefore, activities may take place in various ways. Kanada accepts also an unseen principle, called adrishta, which is the sum total of the potential after effects of previous voluntary activities, in order to explain various activities involving human beings.