The Upanishads are the philosophical-religious texts of Hinduism (also known as Sanatan Dharma meaning “Eternal Order” or “Eternal Path”) which develop and explain the fundamental tenets of the religion. The name is translated as to “sit down closely” as one would to listen attentively to instruction by a teacher or other authority figure.
At the same time, Upanishad has also been interpreted to mean “secret teaching” or “revealing underlying truth”. The truths addressed are the concepts expressed in the religious texts known as the Vedas which orthodox Hindus consider the revealed knowledge of creation and the operation of the universe.
The word veda means “knowledge” and the four Vedas are thought to express the fundamental knowledge of human existence. These works are considered Shruti in Hinduism meaning “what is heard” as they are thought to have emanated from the vibrations of the universe and heard by the sages who composed them orally before they were written down between c. 1500 - c. 500 BCE. The Upanishads are considered the “end of the Vedas” (Vedanta) in that they expand upon, explain, and develop the Vedic concepts through narrative dialogues and, in so doing, encourage one to engage with said concepts on a personal, spiritual level.
There are between 180-200 Upanishads but the best known are the 13 which are embedded in the four Vedas known as:
The Rig Veda is the oldest and the Sama Veda and Yajur Veda draw from it directly while the Atharva Veda takes a different course. All four, however, maintain the same vision, and the Upanishads for each of these address the themes and concepts expressed. The 13 Upanishads are:
Their origin and dating are considered unknown by some schools of thought but, generally, their composition is dated to between c. 800 - c. 500 BCE for the first six (Brhadaranyaka to Kena) with later dates for the last seven (Katha to Mandukya). Some are attributed to a given sage while others are anonymous. Many orthodox Hindus, however, regard the Upanishads, like the Vedas, as Shruti and believe they have always existed. In this view, the works were not so much composed as received and recorded.
The Upanishads deal with ritual observance and the individual's place in the universe and, in doing so, develop the fundamental concepts of the Supreme Over Soul (God) known as Brahman (who both created and is the universe) and that of the Atman, the individual's higher self, whose goal in life is union with Brahman. These works defined, and continue to define, the essential tenets of Hinduism but the earliest of them would also influence the development of Buddhism, Jainism, Sikhism, and, after their translation to European languages in the 19th century CE, philosophical thought around the world.
There are two differing claims regarding the origin of Vedic thought. One claims that it was developed in the Indus Valley by the people of the Harappan Civilization (c. 7000-600 BCE). Their religious concepts were then exported to Central Asia and returned later (c. 3000 BCE) during the so-called Indo-Aryan Migration. The second school of thought, more commonly accepted, is that the religious concepts were developed in Central Asia by the people who referred to themselves as Aryans (meaning “noble” or “free” and having nothing to do with race) who then migrated to the Indus Valley, merged their beliefs and culture with the indigenous people, and developed the religion which would become Sanatan Dharma. The term 'Hinduism' is an exonym (a name given by others to a concept, practice, people, or place) from the Persians who referred to the peoples living across the Indus River as Sindus.
The second claim has wider scholarly support because proponents are able to cite similarities between the early religious beliefs of the Indo-Iranians (who settled in the region of modern-day Iran) and the Indo-Aryans who migrated to the Indus Valley. These two groups are thought to have initially been part of a larger nomadic group which then separated toward different destinations.
Whichever claim one supports, the religious concepts expressed by the Vedas were maintained by oral tradition until they were written down during the so-called Vedic Period of c. 1500 - c. 500 BCE in the Indo-Aryan language of Sanskrit. The central texts of the Vedas themselves, as noted, are understood to be the received messages of the Universe, but embedded in them are practical measures for living a life in harmony with the order the Universe revealed. The texts which deal with this aspect, which are also considered Shruti by orthodox Hindus, are:
Aranyakas – rituals and observances
Brahmanas – commentaries on the rituals
Samhitas – benedictions, mantras, prayers
Upanishads – philosophical dialogues in narrative form
Taken together, the Vedas present a unified vision of the Eternal Order revealed by the Universe and how one is supposed to live in it. This vision was developed through the school of thought known as Brahmanism which recognized the many gods of the Hindu pantheon as aspects of a single God – Brahman – who both caused and was the Universe. Brahmanism would eventually develop into what is known as Classical Hinduism, and the Upanishads are the written record of the development of Hindu philosophical thought.
