Vaisesika Sūtra 1.1.30

संयोगविभागाश्च कर्मणाम् ॥३०॥

saṁyoga-vibhāgāś ca karmaṇām ॥30॥

[संयोग-विभागाः (saṁyoga-vibhāgāḥ) - conjunctions and disjunctions; च (ca) - and; कर्मणाम् (karmaṇām) - of actions;]

Combination and Disjunction comes about by action (karma).