7.1 Foundations of Nyāya logic and reasoning

Nyāya philosophy emphasizes logical reasoning and epistemology. It's all about understanding how we know what we know and how to argue effectively. This school of thought provides a framework for analyzing the world and our knowledge of it.

At its core, Nyāya focuses on four main ways we gain knowledge: perception, inference, comparison, and testimony. It also introduces a five-step method for making logical arguments, helping thinkers avoid common pitfalls in reasoning.

Principles and Epistemology of Nyāya

Principles of Nyāya logic

• Realism posits external world exists independently of perception with objects possessing inherent qualities and relations
• Pluralism acknowledges multiple distinct categories of reality rejecting monistic views (Advaita Vedanta)
• Logical atomism views world composed of discrete indivisible entities (paramāṇus)
• Causality principle asserts every effect has a cause which precedes it temporally
• Nyāya Sūtra foundational text by Gautama outlines 16 categories (padārthas) of philosophical investigation
• Four sources of valid knowledge (pramāṇas) form basis of epistemology

Nyāya epistemology components

• Perception (pratyakṣa) involves direct sensory experience considered most reliable knowledge source
• Inference (anumāna) derives knowledge from observed facts based on invariable concomitance (vyāpti)
• Comparison (upamāna) understands unfamiliar objects by comparing to familiar ones (gavaya to cow)
• Verbal testimony (śabda) acquires knowledge from reliable sources including Vedic scriptures and trustworthy individuals

Nyāya Logic and Reasoning

Significance of Nyāya syllogism

• Five-membered syllogism (pañcāvayava) establishes valid knowledge through systematic reasoning
• Proposition (pratijñā) states thesis to be proved (hill is fiery)
• Reason (hetu) provides grounds for accepting proposition (hill has smoke)
• Example (udāharaṇa) illustrates connection between reason and proposition (kitchen with fire and smoke)
• Application (upanaya) shows how example applies to case at hand (hill has smoke like kitchen)
• Conclusion (nigamana) restates proposition as proven (therefore hill is fiery)

Valid vs invalid Nyāya reasoning

• Valid reasoning (sat-tarka) follows proper syllogistic structure based on true premises leading to true conclusions
• Invalid reasoning (ku-tarka) includes fallacies (hetvābhāsas):
  1. Savyabhicāra inconclusive reason (all shiny things are not silver)
  2. Viruddha contradictory reason (sound is eternal because it is produced)
  3. Prakaraṇasama controversial reason (mind is non-eternal because it is intangible)
  4. Sādhyasama unproven reason (sound is non-eternal because it is audible)
  5. Kālātīta mistimed reason (fire does not exist because there is no smoke yet)
• Pseudo-probans (asiddha) undermines validity:
  • Āśrayāsiddha unestablished subject (horns of a rabbit)
  • Svarūpāsiddha unestablished property (color of air)
  • Vyāpyatvāsiddha unestablished pervasion (all birds can fly)
• Proper reasoning leads to valid knowledge (pramā) essential for philosophical debate and inquiry