Overview
Nyāya (Sanskrit: न्यायः), literally meaning "justice", "rules", "method" or "judgment", is one of the six orthodox (Āstika) schools of Hindu philosophy. Its most significant contributions to Indian philosophy lie in the systematic development of logic, methodology, and treatises on epistemology, which have influenced a wide range of subsequent Indian thought.
Nyāya epistemology accepts four of the six pramāṇas as reliable means of gaining knowledge: pratyakṣa (perception), anumāna (inference), upamāna (comparison and analogy) and śabda (word, the testimony of reliable experts, past or present). Naiyyāyika scholars approached philosophy as a form of direct realism, holding that anything which really exists is in principle humanly knowable. For them, correct knowledge differs from simple, reflexive cognition; it requires anuvyavasāya (अनुव्यवसाय), the cross-examination or reflective cognition of what one thinks one knows.
In its metaphysics, the Nyāya school is closer to the Vaiśeṣika school than to other Hindu traditions. It holds that human suffering arises from mistakes and defects produced by activity carried out under wrong knowledge — notions, ignorance and delusion. Mokṣa (liberation), according to Nyāya, is attained through right knowledge. This premise led the school to concern itself centrally with epistemology, namely the reliable means of gaining correct knowledge and of removing false notions. False knowledge, to Naiyyāyikas, is not merely ignorance but also includes delusion; correct knowledge involves discovering and overcoming one's delusions and understanding the true nature of the soul, the self and reality.
An influential collection of texts on logic and reason is the Nyāya Sūtras, attributed to Akṣapāda Gautama, variously estimated to have been composed between the 6th century BCE and the 2nd century CE. The Nyāya school shares some of its methodology and its concern with the foundations of human suffering with Buddhism. A key difference, however, is that Buddhism holds that there is neither a soul nor a self, while Nyāya,