Hinduism is a religion, or a way of life, found most notably in India and Nepal, Mauritius and Bali (Indonesia). Scholars regard Hinduism as a fusion or synthesis of various Indian cultures and traditions, with diverse roots and no founder. This "Hindu synthesis" started to develop between 500 BCE and 300 CE, after the Vedic times. It has no ecclesiastical order, no unquestionable religious authorities, no governing body, no prophet(s) nor any binding holy book; Hindus can choose to be polytheistic, pantheistic, monotheistic, monistic, agnostic, atheistic or humanist.
There are six orthodox (āstika) schools of thought called darśanas. Each darśana accepts the Vedas as authoritative and the premise that ātman (soul, eternal self) exists. The six darshanas are:
- Sāṃkhya, an atheistic and strongly dualist theoretical exposition of consciousness and matter.
- Yoga, a school emphasising meditation, contemplation and liberation.
- Vedānta, based on the metaphysical and spiritual knowledge found in last segment of in the Vedas, or jñānakāṇḍa.
- Nyāya or logic, explores sources of knowledge.
- Vaiśeṣika, an empiricist school of atomism.
- Mīmāṃsā, an anti-ascetic and anti-mysticist school of orthopraxy.
Of these six darśana, two schools, Vedanta and Yoga, are currently the most prominent.
The Vedas form the earliest record of the Hindu scriptures, and are regarded as eternal truths revealed to the ancient sages (rishis). There are four Vedas - Rigveda, Samaveda, Yajurveda and Atharvaveda. The Upanishads are texts discussing meditation, philosophy and spiritual knowledge, found at the end of each Veda. They are the foundation of Hindu philosophical thought, and have profoundly influenced diverse traditions. There are 108 Muktikā Upanishads in Hinduism, of which between 10 and 13 are variously counted by scholars as Principal Upanishads.
The Mahabharata and the Ramayana are important epics. The Bhagavad Gita is an integral part of the Mahabharata and one of the most popular sacred texts of Hinduism.
The Puranas, which started to be composed from c. 300 CE onward, contain extensive mythologies, and are central in the distribution of common themes of Hinduism through vivid narratives.