hetu

In Buddhist philosophy, hetu refers to a direct cause, as distinguished from an auxiliary or indirect cause known as pratyaya. For example, a seed is a direct cause (hetu) of a plant, while sunshine, water, and earth are auxiliary causes (pratyaya).1

The concept of hetu is also used in Indian logic. In a syllogism, a ground (hetu) is needed to prove a proposition. However, this ground may require a qualification, known as an upadhi, to be accurate. For instance, the presence of smoke can prove fire, but the hetu must be refined to state that smoke is present wherever there is fire in living wood, as smoke is produced by fire in living wood.2