The Brahma Sūtras () are a Sanskrit text, attributed to the sages Bādarāyaṇa and Vyāsa, estimated to have been completed in its surviving form in approx. 400–450 CE, while the original version might be ancient and composed between 600 BCE and 200 BCE. The text systematizes and summarizes the philosophical and spiritual ideas in the Upanishads. The scholar Adi Shankara's interpretation of the Brahmasutra attempted to synthesize diverse and sometimes apparently conflicting teachings of the Upanishads by arguing, as John Koller states: "that Brahman and Atman are, in some respects, different, but, at the deepest level, non-different (advaita), being identical." This view of Vedanta, however, was not universal in Indic thought, and other commentators later held differing views. It is one of the foundational texts of the Vedānta school of Hindu philosophy. The Brahma Sūtras consist of 555 aphoristic verses (sutras) in four chapters. These verses are primarily about the nature of human existence and universe, and ideas about the metaphysical principle of Ultimate Reality called Brahman. The first chapter discusses the metaphysics of Absolute Reality, the second chapter reviews and addresses the objections raised by the ideas of competing orthodox schools of Hindu philosophies such as Nyaya, Yoga, Vaisheshika and Mimamsa as well as heterodox schools such as Buddhism and Jainism, the third chapter discusses epistemology and path to gaining spiritually liberating knowledge, and the last chapter states why such a knowledge is an important human need. The Brahma Sūtras is one of three most important texts in Vedanta along with the Principal Upanishads and the Bhagavad Gita. It has been influential to various schools of Indian philosophies, but interpreted differently by the non-dualistic Advaita Vedanta sub-school, the theistic Vishishtadvaita and Dvaita Vedanta sub-schools, as well as others. Several commentaries on the Brahma Sūtras are lost to history or yet to be found; of the surviving ones, the most well studied commentaries on the Brahma Sūtras include the bhashya by Adi Shankara, Ramanuja, Madhvacharya, Bhaskara and many others. They are also known as the Vedanta Sutra (Sanskrit: वेदान्त सूत्र), deriving this name from Vedanta which literally means the "final aim of the Vedas". Other names for Brahma Sūtras is Shariraka Sutra, wherein Shariraka means "that which lives in the body (Sharira), or the Self, Soul", and Bhikshu-sutra, which literally means "Sutras for monks or mendicants". Author and chronology The Brahma Sūtras or Brahmasutra are attributed to Badarayana. In some