Understanding Nyāya Inference Types

The person observes an effect (sudden rise in water level) and infers its cause (heavy rain on the hilltop). This reasoning process is applied for her personal decision-making (postponing the expedition). According to the Nyāya school, this involves two types of inference:

1. Svārtha Anumāna (Inference for Oneself)

This type of inference is made for one's own understanding and conviction. The person reasons independently to arrive at a conclusion. In this case, the observation and conclusion (about rain and postponing the trip) are for her own benefit.

2. Śeṣavat Anumāna (Inferring Cause from Effect)

This specific method of inference involves observing an effect and inferring its cause. The Nyāya school identifies three types of Anumāna based on the relationship between the perceived sign (linga) and the object to be inferred (sādhya):

• Pūrvavat: Inferring the effect from the cause (e.g., seeing dark clouds and inferring rain).
• Śeṣavat: Inferring the cause from the effect (e.g., seeing a swollen river and inferring past rain). This matches the scenario.
• Sāmānyatodṛṣṭa: Inferring based on a general observation of concomitance, not directly cause-effect (e.g., inferring the movement of senses from observing actions).

The person's reasoning directly applies the Śeṣavat type, moving from the observed effect (water level rise) to the inferred cause (heavy rain).

Conclusion

Therefore, the person's reasoning involves both Svārtha Anumāna (as it's for self-understanding) and Śeṣavat Anumāna (as it infers the cause from the observed effect).