The logical period of Indian thought began with the Kushan dynasty (1st–2nd centuries ce). Gautama (author of the Nyaya-sutras; probably flourished at the beginning of the Christian era) and his 5th-century commentator Vatsyayana established the foundations of the Nyaya as a school almost exclusively preoccupied with logical and epistemological issues. The Madhyamika (“Middle Way”) school of Buddhism—also known as the Shunyavada (“Way of Emptiness”) school—arose, and the analytical investigations of Nagarjuna (c. 200), the great propounder of Shunyavada (dialectical thinking), reached great heights. Though Buddhist logic in the strict sense of the term had not yet come into being, an increasingly rigorous logical style of philosophizing developed among the proponents of these schools of thought.

During the reign of the Guptas, there was a revival of Brahmanism of a gentler and more refined form. Vaishnavism of the Vasudeva cult, centering on the prince-god Krishna and advocating renunciation by action, and Shaivism prospered, along with Buddhism and Jainism. Both the Mahayana and the Hinayana (“Lesser Vehicle”), or Theravada (“Way of the Elders”), schools flourished. The most notable feature, however, was the rise of the Buddhist Yogachara school, of which Asanga (4th century ce) and his brother Vasubandhu were the great pioneers. Toward the end of the 5th century, Dignaga, a Buddhist logician, wrote the Pramanasamuccaya (“Compendium of the Means of True Knowledge”), a work that laid the foundations of Buddhist logic.

The greatest names of Indian philosophy belong to the post-Gupta period from the 7th to the 10th century. At that time Buddhism was on the decline and the Tantric cults were rising, a situation that led to the development of the Tantric forms of Buddhism. Shaivism was thriving in Kashmir and Vaishnavism in the southern part of India. The great philosophers Mimamshakas Kumarila (7th century), Prabhakara (7th–8th centuries), Mandana Mishra (8th century), Shalikanatha (9th century), and Parthasarathi Mishra (10th century) belong to this age. The greatest Indian philosopher of the period, however, was Shankara. All these men defended Brahmanism against the “unorthodox” schools, especially against the criticisms of Buddhism. The debate between Brahmanism and Buddhism was continued, on a logical level, by philosophers of the Nyaya school—Uddyotakara, Vachaspati Mishra, and Udayana (Udayanacharya).

The ultralogical period

Muslim rule in India had consolidated itself by the 11th century, by which time Buddhism, for all practical purposes, had disappeared from the country. Hinduism had absorbed Buddhist ideas and practices and reasserted itself, with the Buddha appearing in Hindu writings as an incarnation of Vishnu. The Muslim conquest created a need for orthodoxy to readjust itself to a new situation. In this period the great works on Hindu law were written. Jainism, of all the “unorthodox” schools, retained its purity, and great Jaina works, such as Devasuri’s Pramananayatattvalokalamkara (“The Ornament of the Light of Truth of the Different Points of View Regarding the Means of True Knowledge,” 12th century ce) and Prabhachandra’s Prameyakamalamartanda (“The Sun of the Lotus of the Objects of True Knowledge,” 11th century ce), were written during this period. Under the Chola kings (c. 850–1279) and later in the Vijayanagara kingdom (which, along with Mithila in the north, remained strongholds of Hinduism until the middle of the 16th century), Vaishnavism flourished. The philosopher Yamunacharya (flourished 1050 ce) taught the path of prapatti, or complete surrender to God. The philosophers Ramanuja (11th century), Madhva, and Nimbarka (c. 12th century) developed theistic systems of Vedanta and severely criticized Shankara’s Advaita Vedanta.

Toward the end of the 12th century, creative work of the highest order began to take place in the fields of logic and epistemology in Mithila and Bengal. The 12th–13th-century philosopher Gangesa’s Tattvachintamani (“The Jewel of Thought on the Nature of Things”) laid the foundations of the school of Navya-Nyaya (“New Nyaya”). Four great members of this school were Pakshadhara Mishra of Mithila, Vasudeva Sarvabhauma (16th century), his disciple Raghunatha Shiromani (both of Bengal), and Gadadhara Bhattacharyya.

Religious life was marked by the rise of great mystic saints, chief of which are Ramananda, Kabir, Chaitanya, and Guru Nanak, who emphasized the path of bhakti, or devotion, a wide sense of humanity, freedom of thought, and a sense of unity of all religions. Somewhat earlier than these were the great Muslim Sufi (mystic) saints, including Khwāja Muʾin-ud-Din Ḥasan, who emphasized asceticism and taught a philosophy that included both love of God and love of humanity.

The British period in Indian history was primarily a period of discovery of the ancient tradition (e.g., the two histories by Radhakrishnan, scholar and president of India from 1962 to 1967, and S.N. Dasgupta) and of comparison and synthesis of Indian philosophy with the philosophical ideas from the West. Among modern creative thinkers have been Mohandas K. Gandhi, who espoused new ideas in the fields of social, political, and educational philosophy; Sri Aurobindo, an exponent of a new school of Vedanta that he calls Integral Advaita; and K.C. Bhattacharyya, who developed a phenomenologically oriented philosophy of subjectivity that is conceived as freedom from object.