Define Vyapti.

Vyapti is a term from Indian philosophy, particularly within the context of Nyaya and Vaisheshika schools, representing the concept of invariable concomitance or the relation between a hetu (reason) and a sadhya (probandum or the proposition to be proved). Vyapti is crucial in the process of inference (anumana) and is instrumental in establishing a causal or logical connection between two events or phenomena.

Key features of Vyapti include:

1. Universal Concomitance: Vyapti signifies the universal and invariable concomitance between the presence of a hetu and the presence of a sadhya. In other words, where there is smoke (hetu), there is fire (sadhya).

2. Basis of Inference: Vyapti forms the foundation for logical inference. By observing a specific relation between the reason and the consequent in a particular instance, one can infer the presence of the consequent based on the presence of the reason in other instances.

3. Three Components: Vyapti involves three components – the hetu (reason), the sadhya (probandum), and the vyapti (universal concomitance). The vyapti is the essential link that establishes the invariable connection between the hetu and the sadhya.

4. Necessary Condition: Vyapti suggests that the presence of the hetu is a necessary condition for the presence of the sadhya. It is through this principle that inference gains epistemic validity.

Vyapti, as a foundational concept in Nyaya-Vaisheshika epistemology, provides a systematic framework for reasoning and drawing valid conclusions based on observed regularities and causal connections in the world.