In ancient Indian philosophy (before 100 BC), philosophy and religion cannot be meaningfully separated, primarily because of the cultural integration of religious practices and mystical pursuits. For example, ceremonies celebrating birth, marriage, and death, performed with recitations of Vedic verses (mantras), were important for bonding within ancient Indian societies. Later in classical Indian philosophy, different social practices developed.
Thus, the orthodox classical schools of thought are distinguished from nonorthodox classical schools by their allegiance to established forms of social practice rather than to the doctrines of the Veda. Buddhism, for example, constitutes much more of a break with Vedic practices than with the ideas developed in Vedic traditions of thought. In fact, the Upanishads, mystical treatises continuous with the Vedas, foretell many Buddhist teachings.
In ancient India, religion did not entail dogma, but rather a way of life that permitted a wide range of philosophic positions and inquiry. Mysticism, the claim that ultimate truth is only obtainable through spiritual experience, dominates much ancient Indian philosophy. Such experiences are thought to reveal a supreme and transmundane (beyond ordinary experience) reality and to provide the meaning of life. Mysticism shapes much classical and modern Indian thought as well.
Through meditation and the meditative techniques of yoga, it is believed that one discovers one’s true self (atman), or God (Brahman), or enlightenment (nirvana). The presumed indications of mystical experiences, such as atman or God, were especially debated in the ancient period and influenced much subsequent Indian philosophy, including the reflections of professional philosophers of late classical times. In some schools of classical Indian philosophy, such as Nyaya (Logic), neither religion nor mysticism is central.
Rather, the questions of how human beings know what they know—and how they can mean what they say—are given priority. The term Indian philosophy (Sanskrit: Darshanas), may refer to any of several traditions of philosophical thought that originated in the Indian subcontinent, including Hindu philosophy, Buddhist philosophy, and Jain philosophy. Having the same or rather intertwined origins, all of these philosophies have a common underlying theme of Dharma, and similarly attempt to explain the attainment of emancipation.
They have been formalized and promulgated chiefly between 1000 BC to a few centuries AD, with residual commentaries and reformations continuing up to as late as the 20th century by Aurobindo and ISKCON among others, who provided stylized interpretations. In the history of the Indian subcontinent, following the establishment of a Vedic culture, the development of philosophical and religious thought over a period of two millennia gave rise to what came to be called the six schools of astika, or orthodox, Indian or Hindu philosophy.
These schools have come to be synonymous with the greater religion of Hinduism, which was a development of the early Vedic religion. Religion (from Latin religio, “reverence for the gods”, “piety”, possibly related to religare, “to bind”) is the belief in and worship of a god or gods, or more in general a set of beliefs explaining the existence of and giving meaning to the universe, usually involving devotional and ritual observances, and often containing a moral code governing the conduct of human affairs. 
Aspects of religion include narrative, symbolism, beliefs, and practices that are supposed to give meaning to the practitioner’s experiences of life. Whether the meaning centers on a deity or deities, or an ultimate truth, religion is commonly identified by the practitioner’s prayer, ritual, meditation, music and art, among other things, and is often interwoven with society and politics. It may focus on specific supernatural, metaphysical, and moral claims about reality (the cosmos and human nature) which may yield a set of religious laws and ethics and a particular lifestyle.
Religion also encompasses ancestral or cultural traditions, writings, history, and mythology, as well as personal faith and religious experience. The development of religion has taken many forms in various cultures, with continental differences. The term “religion” refers both to the personal practices related to communal faith and to group rituals and communication stemming from shared conviction. “Religion” is sometimes used interchangeably with “faith” or “belief system”, but it is more socially defined than personal convictions, and it entails specific ehaviors, respectively. Religion is often described as a communal system for the coherence of belief focusing on a system of thought, unseen being, person, or object, that is considered to be supernatural, sacred, divine, or of the highest truth. Moral codes, practices, values, institutions, tradition, rituals, and scriptures are often traditionally associated with the core belief, and these may have some overlap with concepts in secular philosophy. Religion is also often described as a “way of life” or a life stance.
Hindu philosophy constitutes an integral part of the culture of South Asia, and is the first of the Dharmic philosophies which were influential throughout the Far East. The great diversity in thought and practice of Hinduism is nurtured by its liberal universalism. The Indian caste system (pronounced /? k? st/ or /? k?? st/) describes the system of social stratification and social restrictions in the Indian subcontinent in which social classes are defined by thousands of endogamous hereditary groups, often termed jatis or castes.
Within a jati, there exist exogamous groups known as gotras, the lineage or clan of an individual. In a handful of sub-castes such as Shakadvipi, endogamy within a gotra is permitted and alternative mechanisms of restricting endogamy are used (e. g. banning endogamy within a surname). Although generally identified with Hinduism, the caste system was also observed among followers of other religions in the Indian subcontinent, including some groups of Muslims and Christians. 1] Caste barriers have mostly broken down in large cities, though they persist in rural areas of the country, where 72% of India’s population resides. None of the Hindu scriptures endorses caste-based discrimination, and the Indian Constitution has outlawed caste-based discrimination, in keeping with the secular, democratic principles that founded the nation.  Nevertheless, the caste system, in various forms, continues to survive in modern India because of a combination of political factors and social perceptions and behavior.