Advaita Vedanta is a philosophical school of thought within Hinduism, founded by Adi Shankaracharya in the 8th century. The term "Advaita" means non-dual or without a second, and "Vedanta" refers to the end or conclusion of the Vedas, the ancient Hindu scriptures. Thus, Advaita Vedanta can be understood as the non-dualistic interpretation of the Vedas.

At its core, Advaita Vedanta teaches that there is only one ultimate reality, which is Brahman, the absolute consciousness or universal soul. This Brahman is beyond all concepts and limitations, and is the source of all existence. It is the ultimate truth that exists in everything and everyone, and everything else is just a manifestation of this one reality.

According to Advaita Vedanta, the world we perceive is an illusion, known as Maya. It is a result of our ignorance and attachment to the material world. This illusion creates a sense of duality, where we see ourselves as separate from others and the world around us. However, in reality, there is no separation, and everything is interconnected and part of the same ultimate reality.

The goal of Advaita Vedanta is to attain liberation, known as moksha, from this illusion of duality and realize our true nature as Brahman. This can be achieved through self-inquiry and the practice of yoga, meditation, and other spiritual disciplines. By understanding that we are not separate individuals, but rather a part of the universal consciousness, we can break free from the cycle of birth and death and attain ultimate bliss and unity with Brahman.

One of the key teachings of Advaita Vedanta is the concept of "neti neti," which means "not this, not that." It encourages individuals to detach themselves from their identification with the body, mind, and ego, and instead focus on their true nature as Brahman. This detachment leads to the realization that the individual self, or Atman, is not separate from Brahman.

In conclusion, Advaita Vedanta is a profound philosophical system that emphasizes the unity and oneness of all existence. It teaches that the ultimate reality is non-dual and all-encompassing, and that liberation can be achieved by realizing this truth. Adi Shankaracharya's teachings have had a lasting impact on Hinduism and continue to inspire seekers of truth to this day.