Vaisesika Sūtra 2.1.23

संयोगादऽभावः कर्मणः ॥२३॥

saṁyogāda'bhāvaḥ karmaṇaḥ ॥23॥

[संयोगात् अभावः कर्मणः॥
saṁyogāt = from contact or association; abhāvaḥ = absence; karmaṇaḥ = of action॥]

(space is not distinguished for) action because of absence of contact or association.