Vaisesika Sūtra 2.1.19

प्रत्यक्षप्रवृत्तत्वात् संज्ञाकर्मणः ॥१९॥

pratyakṣapravr̥ttatvāt saṁjñākarmaṇaḥ ॥19॥

[प्रत्यक्ष प्रवृत्तत्वात् संज्ञा कर्मणः॥
pratyakṣa = direct perception; pravr̥ttatvāt = by its nature of being; saṁjñā = name; karmaṇaḥ = action;॥]

As Name and Action, by its nature of being, are directly perceptible.