According to Nyāya, Karaṇa (the instrumental cause) is classified as

In Nyāya philosophy, causes (Kāraṇa) are classified into three categories: Samavāyī Kāraṇa (inherent or material cause, ), Asamavāyī Kāraṇa (non-inherent cause, ), and Nimitta Kāraṇa (efficient or instrumental cause, ). Karaṇa denotes the special or principal instrumental cause (asādhāraṇa kāraṇa) by means of which an agent brings about an effect, and is classified under Nimitta Kāraṇa .