The main philosophers of the medieval Vaisnavism have been noted above. Vaisnavism, however, has a long history, traceable to the Vishnu worship of the Rigveda, the Bhakti conception of the epics, and the Vasudeva cult of the pre-Christian era. Of the two main Vaisnava scriptures, or agamas, the Pancaratra ("Relating to the Period of Five Nights") and the Vaikhanasa ("Relating to a Hermit or Ascetic") are the most important. Though Vaisnava philosophers trace the Pancaratra works to Vedic origin, absolutists such as Shankara refused to acknowledge this claim. The main topics of the Pancaratra literature concern rituals and forms of image worship and religious practices of the Vaisnavas. Of philosophical importance are the Ahirbudhnya-samhita ("Collection of Verses for Shiva") and Jayakhya-samhita ("Collection of Verses Called Jaya"). The most well-known Pancaratra doctrine concerns the four spiritual forms of God: the absolute, transcendent state, known as Vasudeva; the form in which knowledge and strength predominate (known as Samkarsana); the form in which wealth and courage predominate (known as Pradyumna); and the form in which power and energy predominate (known as Aniruddha). Shankara identified Samkarsana with the individual soul, Pradyumna with mind, and Aniruddha with the ego sense. Furthermore, five powers of God are distinguished: creation, maintenance, destruction, favour, and disfavour. Bhakti is regarded as affection for God and associated with a sense of his majesty. The doctrine of prapatti, or complete self-surrender, is emphasized.
 
 

The Shaiva schools are the philosophical systems within the fold of Shaivism, a religious sect that worships Shiva as the highest deity. There is a long tradition of Shiva worship going back to the Rudra hymns of the Rigveda, the Shiva-Rudra of the Vajasaneyi-Samhita, the Atharvaveda, and the Brahmanas. 
Madhava in his Sarva-darshana-samgraha referred to three Shaiva systems: the Nakulisha-Pashupata, the Shaiva, and the Pratyabhijna systems. The Shaiva system of Madhava's classification probably corresponds to Shaiva-siddhanta of Tamil country, and the Pratyabhijna is known as Kashmir Shaivism. The Shaiva-siddhanta is realistic and dualistic; the Kashmir system is idealistic and monistic.
 
 

The source literature of the Shaiva-siddhanta school consists of the Agamas, Tamil devotional hymns written by Shaiva saints but collected by Nambi (c. AD 1000) in a volume known as Tirumurai, Civa-nana-potam ("Understanding of the Knowledge of Shiva") by Meykantatevar (13th century), Shivacarya's Shiva-jnana-siddhiyar ("Attainment of the Knowledge of Shiva"), Umapati's Shivaprakasham ("Lights on Shiva") in the 14th century, Shrikantha's commentary on the Vedanta-sutras (14th century), and Appaya Diksita's commentary thereon. This school admits three categories (padarthas): God (Shiva or Pati, Lord), soul (pashu), and the bonds (pasha), and the 36 principles (tattvas). These 36 are divided into three groups: at the top, in order of manifestation from Shiva, are the five pure principles--shivatattva (the essence of Shiva), shakti (power), sada-shiva (the eternal good), ishivara (lord), and shuddha-vidya (true knowledge); seven mixed principles--pure maya, five envelopes (destiny, time, interest, knowledge, and power), and purusa, or self; and 24 impure principles beginning with prakrti (this list is broadly the same as that of Samkhya). Shiva is the first cause: his shakti, or power, is the instrumental cause, maya the material cause. This maya-shakti is not God's essential power but is assumed by him; it is parigraha-shakti ("Assumed Power"). The relation of Shiva to his essential power is one of identity. Bonds are of three kinds: karma, maya, and avidya. The world and souls are real, and emancipation requires the grace of Shiva. The Shaiva-siddhanta always insisted on the preservation of the individuality of the finite soul, even in the state of emancipation, and rejected Shankara's nondualism. Appaya Diksita's commentary shows the tendency to attempt a reconciliation between the Agama tradition of realism and pluralism with the Advaita tradition. The soul is eternal and all-pervasive, but, owing to original ignorance, it is reduced to the condition of anava, which consists in regarding oneself as finite and atomic. Knowledge of its own nature as well as God's is possible only by God's grace.
 
 

The source literature of this school consists in the Shiva-sutra, Vasugupta's Spanda-karika ("Verses on Creation"; 8th-9th centuries), Utpala's Pratyabhijña-sutra ("Aphorisms on Recognition"; c. 900), Abhinavagupta's Paramarthasara ("The Essence of the Highest Truth"), Pratyabhijña-vimarshini ("Reflections on Recognition"), and Tantraloka ("Lights on the Doctrine") in the 10th century, and Ksemaraja's Shiva-sutra-vimarshini ("Reflections on the Aphorisms on Shiva"). As contrasted with the Shaiva-siddhanta, this school is idealist and monist, and, although it accepts all the 36 tattvas and the three padarthas, it is Shiva, the Lord, who is the sole reality. God is viewed as both the material and efficient cause of the universe. Five aspects of God's power are distinguished: consciousness (cit), bliss (ananda), desire (iccha), knowledge (jnana), and action (kriya). Shiva is one--without a second, infinite spirit. He has a transcendent aspect and an immanent aspect, and his power with its fivefold functions constitutes his immanent aspect. The individual soul of a person is identical with Shiva; recognition of this identity is essential to liberation.
 
 

Jainism, founded in about the 6th century BC by Vardhamana Mahavira, the 24th in a succession of religious leaders known as Jinas (Conquerors), rejects the idea of God as the creator of the world but teaches the perfectibility of man, to be accomplished through the strictly moral and ascetic life. Central to the moral code of Jainism is the doctrine of ahimsa, or noninjury to all living beings, an idea that may have arisen in reaction to Vedic sacrifice ritual. There is also a great emphasis on vows (vratas) of various orders.

 Although earlier scriptures, such as the Bhagavati-sutra, contained assorted ideas on logic and epistemology, Kundakunda of the 2nd century AD was the first to develop Jaina logic. The Tattvarthadhigama-sutra of Umasvatis, however, is the first systematic work, and Siddhasena (7th century AD) the first great logician. Other important figures are Akalanka (8th century), Manikyanandi, Vadideva, Hemchandra (12th century), Prabhachandra (11th century), and Yasovijaya (17th century).

 The principal ingredients of Jaina metaphysics are: an ultimate distinction between "living substance" or "soul" ( jiva) and "nonliving substance" (ajiva); the doctrine of anekantavada, or nonabsolutism (the thesis that things have infinite aspects that no determination can exhaust); the doctrine of naya (the thesis that there are many partial perspectives from which reality can be determined, none of which is, taken by itself, wholly true, but each of which is partially so); and the doctrine of karma, in Jainism a substance, rather than a process, that links all phenomena in a chain of cause and effect.

 As a consequence of their metaphysical liberalism, the Jaina logicians developed a unique theory of seven-valued logic, according to which the three primary truth values are "true," "false," and "indefinite," and the other four values are "true and false," "true and indefinite," "false and indefinite," and "true, false, and indefinite." Every statement is regarded as having these seven values, considered from different standpoints.

 Knowledge is defined as that which reveals both itself and another (svaparabhasi). It is eternal, as an essential quality of the self; it is noneternal, as the perishable empirical knowledge. Whereas most Hindu epistemologists regarded pramana as the cause of knowledge, the Jainas identified pramana with valid knowledge. Knowledge is either perceptual or nonperceptual. Perception is either empirical or nonempirical. Empirical perception is either sensuous or nonsensuous. The latter arises directly in the self, not through the sense organs, but only when the covering ignorance is removed. With the complete extinction of all karmas, a person attains omniscience (kevala-jnana). 
 
 

Reference has been made earlier to the Sufi (Islamic mystics), who found a resemblance between the ontological monism of Ibn al-'Arabi and that of Vedanta. The Shattari order among the Indian Sufis practiced Yogic austerities and even physical postures. Various minor syncretistic religious sects attempted to harmonize Hindu and Muslim religious traditions at different levels and with varying degrees of success. Of these, the most famous are Ramananda, Kabir, and Guru Nanak. Kabir harmonized the two religions in such a manner that, to an enquiry about whether he was a Hindu or a Muslim, the answer given by a contemporary was "It is a secret difficult to comprehend. One should try to understand." Guru Nanak rejected the authority of both Hindu and Muslim scriptures alike and founded his religion (Sikhism) on a rigorously moralistic, monotheistic basis.

 Among the great Mughals, Akbar attempted, in 1581, to promulgate a new religion, Din-e Ilahi, which was to be based on reason and ethical teachings common to all religions and which was to be free from priestcraft. This effort, however, was short-lived, and a reaction of Muslim orthodoxy was led by Shaykh Ahmed Sirhindi, who rejected ontological monism in favour of orthodox unitarianism and sought to channel mystical enthusiasm along Qur`anic (Islamic scriptural) lines. By the middle of the 17th century, the tragic figure of Dara Shikoh, the Mughal emperor Shah Jahan's son and disciple of the Qadiri sufis, translated Hindu scriptures, such as the Bhagavadgita and the Upanisads, into Persian and in his translation of the latter closely followed Shankara's commentaries. In his Majma' al-bahrayn he worked out correlations between Sufi and Upanisadic cosmologies, beliefs, and practices. During this time, the Muslim elite of India virtually identified Vedanta with Sufism. Later, Shah Wali Allah's son, Shah 'Abd-ul-'Aziz, regarded Krishna among the awliya` (saints).
 
 

In the 19th century, India was not marked by any noteworthy philosophical achievements, but the period was one of great social and religious reform movements. The newly founded universities introduced Indian intellectuals to Western thought, particularly to the empiricistic, utilitarian, and agnostic philosophies in England, and John Stuart Mill, Jeremy Bentham, and Herbert Spencer had become the most influential thinkers in the Indian universities by the end of the century. These Western-oriented ideas served to generate a secular and rational point of view and stimulated social and religious movements, most noteworthy among them being the Brahmo (Brahma) Samaj movement founded by Rammohan Ray. Toward the later decades of the century, the great saint Ramakrishna Paramahamsa of Calcutta renewed interest in mysticism, and many young rationalists and skeptics were converted into the faith exemplified in his person. Ramakrishna taught, among other things, an essential diversity of religious paths leading to the same goal, and this teaching was given an intellectual form by Swami Vivekananda, his famed disciple.

 The first Indian graduate school in philosophy was founded in the University of Calcutta during the first decades of the 20th century, and the first incumbent of the chair of philosophy was Sir Brajendranath Seal, a versatile scholar in many branches of learning, both scientific and humanistic. Seal's major published work is The Positive Sciences of the Ancient Hindus, which, besides being a work on the history of science, shows interrelations among the ancient Hindu philosophical concepts and their scientific theories. Soon, however, the German philosophers Kant and Hegel came to be the most studied philosophers in the Indian universities. The ancient systems of philosophy came to be interpreted in the light of German idealism. The Hegelian notion of Absolute Spirit found a resonance in the age-old Vedanta notion of Brahman. The most eminent Indian Hegelian scholar is Hiralal Haldar, who was concerned with the problem of the relation of the human personality with the Absolute, as is evidenced by his book Neo-Hegelianism. The most eminent Kantian scholar is K.C. Bhattacharyya.

 Among those who deserve mention for their original contributions to philosophical thinking are Sri Aurobindo (died 1950), Mahatma Gandhi (died 1948), Rabindranath Tagore (died 1941), Sir Muhammed Iqbal (died 1938), K.C. Bhattacharyya (died 1949), and Sarvepalli Radhakrishnan (died 1975). Of these, Sri Aurobindo was first a political activist and then a yogin, Tagore and Iqbal poets, Gandhi a political and social leader, and only Radhakrishnan and Bhattacharyya university professors. This fact throws some light on the state of Indian philosophy in this century.

 In his major work, The Life Divine, Sri Aurobindo starts from the fact of human aspiration for a kingdom of heaven on earth and proceeds to give a theoretical framework in which such an aspiration would be not a figment of imagination but a drive in nature, working through man toward a higher stage of perfection. Both the denial of the materialist and that of the ascetic are rejected as being one-sided. The gulf between unconscious matter and fully self-conscious spirit is sought to be bridged by exhibiting them as two poles of a series in which spirit continuously manifests itself. The Vedantic concept of a transcendent and all-inclusive Brahman is sought to be harmonized with a theory of emergent evolution. Illusionism is totally rejected. The purpose of man is to go beyond his present form of consciousness. Yoga is interpreted as a technique not for personal liberation but for cooperating with the cosmic evolutionary urge that is destined to take mankind ahead from the present mental stage to a higher, supramental stage of consciousness. A theory of history, in accordance with this point of view, is worked out in his The Human Cycle.

 Rabindranath Tagore's philosophical thinking is no less based on the Upanisads, but his interpretation of the Upanisads is closer to Vaisnava theism and the Bhakti cults than to traditional monism. He characterized the absolute as supreme person and placed love higher than knowledge. In his Religion of Man, Tagore sought to give a philosophy of man in which human nature is characterized by a concept of surplus energy that finds expression in creative art. In his lectures on Nationalism, Tagore placed the concept of society above that of the modern nation-state.

 Mahatma Gandhi preferred to say that the truth is God rather than God is the truth, because the former proposition expresses a belief that even the atheists share. The belief in the presence of an all-pervading spirit in the universe led Gandhi to a strict formulation of the ethics of nonviolence  (ahimsa). But he gave this age-old ethical principle a wealth of meaning so that ahimsa for him became at once a potent means of collective struggle against social and economic injustice, the basis of a decentralized economy and decentralized power structure, and the guiding principle of one's individual life in relation both to nature and to other persons. The unity of existence, which he called the truth, can be realized through the practice of ahimsa, which requires reducing oneself to zero and reaching the furthest limit of humility.

 Influenced by the British philosopher J.M.E. McTaggart's form of Hegelian idealism and the French philosopher Henri Bergson's philosophy of change, Muhammed Iqbal conceived reality as creative and essentially spiritual, consisting of egos. "The truth, however, is that matter is spirit," he wrote,

Citaz: In space-time reference. The unity called man is body when we look at it as acting in regard to what we call external world; it is mind or soul when we look at it as acting in regard to the ultimate aim and ideal of such acting.

Citaz: Influenced by British Neo-Hegelianism in his interpretation of the Vedantic tradition, Sarvepalli Radhakrishnan was primarily an interpreter of Indian thought to the Western world. He defended a realistic interpretation of the concept of maya--thereby playing down its illusionistic connotation, a theory of intuition as the means of knowing reality, and a theory of emergent evolution of spirit (not unlike Sri Aurobindo, but without his doctrine of supermind) in nature and history. The most original among modern Indian thinkers, however, is K.C. Bhattacharyya, who rejected the conception of philosophy as a construction of a worldview and undertook a phenomenological description of the various grades of subjectivity: (1) the bodily, (2) the psychic, and (3) the spiritual. With regard to (1), he distinguished between the objective body and the felt body and regarded the latter as the most primitive level of the subjective sense of freedom from the objective world. The stage (2) includes the range of mental life from image to free thought. In introspection, the level (2) is transcended, but various levels of introspection are distinguished, all leading to greater freedom from objectivity. It would seem, however, that for Bhattacharyya absolute freedom from objectivity was a spiritual demand. According to his theory of value, value is not an adjective of the object but a feeling absolute, of which the object evaluated appears as an adjective, and his logic of alternation is a modern working out of the Jaina theories of anekanta (non-absolutism) and syadvada (doctrine of "may be").

 Among later philosophers, N.V. Banerjee (1901-81) and Kalidas Bhattacharyya (1911-84), the son of K.C. Bhattacharyya, have made important contributions. In Language, Meaning and Persons (1963), Banerjee examines the development of personhood from a stage of individualized bondage to liberation in a collective identity, a life-with-others. This liberation, according to Banerjee, also entails an awareness of time and freedom from spatialized objects.
 In his earlier writings such as Object, Content and Relation (1951) and Alternative Standpoints in Philosophy (1953), Bhattacharyya developed his father's idea of theoretically undecidable alternatives in philosophy. In the later works Philosophy, Logic and Language (1965) and Presuppositions of Science and Philosophy (1974), he developed the concept of metaphysics as a science of the nonempirical a priori essences that are initially discerned as the structure of the empirical but are subsequently recognized as autonomous entities. The method of metaphysics for him is reflection, phenomenological and transcendental. Kalidas Bhattacharyya was concerned with the nature and function of philosophical reflection and its relation of unreflective experience. What reflection brings to light, he held, is present in pre-reflective experience, but only as undistinguished and fused, in a state of objective implicitness. The essences as such are not real but demand realization in pure reflective consciousness. At the same time, he emphasized the limitations of any doctrine positing the constitution of nature in consciousness. Such a doctrine, he insisted, cannot be carried out in details.

 Among those who apply the phenomenological method and concepts to understanding the traditional Indian philosophies, D. Sinha, R.K. Sinari, and J.N. Mohanty are especially noteworthy. Others who interpret the Indian philosophies by means of the methods and concepts of analytical philosophy include B.K. Matilal and G. Misra. In the field of philosophy of logic, P.K. Sen has worked on the paradoxes of confirmation and the concept of quantification, and Sibajiban on the liar paradox and on epistemic logic. Sibajiban and Matilal have made important contributions toward rendering the concepts of Navya-Nyaya logic into the language of modern logic. In ethics and social philosophy, notable work has been done by Abu Sayyid Ayub, Daya Krishna, Rajendra Prasad, and D.P. Chattopadhyaya.