Vishishtadvaita is a school of Hindu philosophy that was founded by Ramanuja, a prominent theologian and philosopher in the 11th century. The term Vishishtadvaita is derived from the Sanskrit words "vishishta", which means qualified or special, and "advaita", which means non-dualism. Therefore, Vishishtadvaita can be translated as "qualified non-dualism".

This philosophy is based on the teachings of the Upanishads, which are ancient Hindu scriptures that discuss the nature of reality and the relationship between the individual soul and the ultimate reality, Brahman. According to Vishishtadvaita, Brahman is the ultimate reality and the source of all existence. However, unlike other schools of Hindu philosophy, Vishishtadvaita believes that the individual souls are not separate from Brahman, but rather, they are a part of Brahman.

In Vishishtadvaita, the individual souls are considered to be "qualified" or "special" as they possess qualities and attributes that are similar to those of Brahman. This is in contrast to other schools of Hindu philosophy, such as Advaita Vedanta, which believe in the complete identity of the individual soul and Brahman. Ramanuja argued that the individual souls are distinct from Brahman, but they are also intimately connected to it.

One of the key principles of Vishishtadvaita is the concept of "Brahman, soul, and matter". According to this philosophy, the universe is made up of three fundamental entities – Brahman, the ultimate reality, the individual souls, and matter. Brahman is the supreme consciousness that pervades everything in the universe, including the individual souls and matter. The individual souls, on the other hand, are considered to be a reflection of Brahman and are inseparable from it. Matter, which includes the physical world and all its objects, is seen as a manifestation of Brahman.

Another important aspect of Vishishtadvaita is the concept of "prapatti", which means surrender to God. Ramanuja believed that the ultimate goal of human life is to achieve moksha, or liberation from the cycle of birth and death. In Vishishtadvaita, this can be attained through the practice of bhakti, or devotion to God, and prapatti, which is complete surrender to God. By surrendering to God, one can attain union with Brahman and ultimately, liberation.

In conclusion, Vishishtadvaita is a philosophy that emphasizes the unity of all beings with Brahman, while also recognizing the individuality of the soul. It encourages the practice of devotion and surrender to God as a means of achieving liberation. Ramanuja's teachings have had a significant influence on Hinduism, and Vishishtadvaita continues to be a popular school of thought among Hindus today.