According to these [widely represented contemporary] studies, Shankara only accorded a provisional validity to the knowledge gained by inquiry into the words of the Śruti (Vedas) and did not see the latter as the unique source (pramana) of Brahmajnana. The affirmations of the Śruti, it is argued, need to be verified and confirmed by the knowledge gained through direct experience (anubhava) and the authority of the Śruti, therefore, is only secondary.— Anantanand Rambachan
Stcherbatsky in 1927 criticized Shankara for demanding the use of logic from Madhyamika Buddhists, while himself resorting to revelation as a source of knowledge. Sircar in 1933 offered a different perspective and stated, "Sankara recognizes the value of the law of contrariety and self-alienation from the standpoint of idealistic logic; and it has consequently been possible for him to integrate appearance with reality."
According to King and Roodurmun, until the 10th century Shankara was overshadowed by his older contemporary Mandana-Misra, the latter considered to be the major representative of Advaita. Other scholars state that the historical records for this period are unclear, and little reliable information is known about the various contemporaries and disciples of Shankara. For Example, Advaita tradition holds that Mandana-Misra is the same person as Suresvara, a name he adopted after he became a disciple of Shankara after a public debate which Shankara won.
He introduced the Pañcāyatana form of worship, the simultaneous worship of five deities – Ganesha, Surya, Vishnu, Shiva and Devi. Shankara explained that all deities were but different forms of the one Brahman, the invisible Supreme Being.
There are at least fourteen different known biographies of Adi Shankara's life. Many of these are called the Śankara Vijaya, while some are called Guruvijaya, Sankarabhyudaya and Shankaracaryacarita. Of these, the Brhat-Sankara-Vijaya by Citsukha is the oldest hagiography but only available in excerpts, while Sankaradigvijaya by Vidyaranya and Sankaravijaya by Anandagiri are the most cited. Other significant biographies are the Mādhavīya Śaṅkara Vijayaṃ (of Mādhava, c. 14th century), the Cidvilāsīya Śaṅkara Vijayaṃ (of Cidvilāsa, c. between the 15th and 17th centuries), and the Keraļīya Śaṅkara Vijayaṃ (of the Kerala region, extant from c. the 17th century). These, as well as other biographical works on Shankara, were written many centuries to a thousand years after Shankara's death, in Sanskrit and non-Sanskrit languages, and the biographies are filled with legends and fiction, often mutually contradictory.