Adi Sankaracharya's life was dedicated to a quest for spiritual truth. His views on Advaita are best summed up in his own words: Brahma satyam jagat mithya, Jiva brahmaiva naparah; the Brahman alone is real, the world is illusory, the individual and Universal Soul are one. This pronouncement is in contrast to other thought-systems of the time, like Ramanujacharya's Vishishtadvaita which treads a middle ground by focusing on the relation between the world and God; and Madhva's dvaita or dualistic world-view.
Sankara's Bhasya is essentially a treatise on the Brahma-Sutras of Vyasa, 555 aphorisms that contain the quintessence of Upanishadic thought. His deliberations, as of most Vedantists, are triggered by the call of the very first sutra: Athato Brahma Jignasa - now therefore the inquiry into Brahman . This is a call to free inquiry, which sets the tone of all speculation.
Sankara's appeal lay as much in his erudition and dialectical skills as in his being a child prodigy. In a short life of 33 years, he set ablaze the intellectual world, redefining, revamping and revitalising old concepts with power and humility. From the backwaters of Kaladi in Kerala to the northern Gangetic plains, Sankara took on scholars, sages and savants in challenging debates.
When it came to rituals, he was a rebel as is evident in his insistence on performing the last rites of his mother despite being a sanyasi and that too in the backyard of his ancestral house. But most of all, Sankara was a young sage who reached out and inspired the masses to renew their faith through intense devotional lyrics and simple hymns like the Bhaja Govindam and the Saundaryalahari .
Sankara's two-level theory of the Brahman is at once abstruse and simple, as detailed in his magnum opus Brahma-sutra Bhashya , and also in smaller masterpieces like Atma-Bodha and Vivekachudamani . He perceives the Brahman as being essentially featureless, nirguna , but manifesting itself with attributes, saguna , and that nirguna is ultimately real and saguna , false. This Brahman -world relation he illustrates with the snake-rope analogy where the illusion is mistaking a rope for a snake.
Sankara uses everyday metaphors and similies to illustrate advaitic concepts, comparing at one point the practice of knowledge ( Jnana-Abhyasa ), which purifies by removing ignorance with the method of purifying muddy water with kataka-nut powder. Just as powder sprinkled on the surface of water forms a film and drags all impurities to the bottom leaving pure water on the surface, constant practice and use of knowledge removes the dirt of ignorance. Also, like the kataka-nut powder, which merges into the water after doing its work, knowledge too disappears after the Self emerges.
Sankara also used the analogy of mistaking oyster-shells scattered along a beach on a moonlit night for silver. Just as the illusion of silver lasts in the perceiver's mind only till he recognises the reality of oyster-shells, so too does the world of names and forms exist till Self-Knowledge dawns. Sankara reinforces the spirit and content of the Upanishads by alluding to the Mahavakyas in his delineation of the nature of Brahman , reiterating the well-known method of arriving at the nature of the Brahman by practising neti, neti , not this, not this.
Sankara was a seminal thinker but no less a great apostle of bhakti . Hence he had mass appeal. His devotional outpourings were meant to inspire people to their innate divine self. His own life was exemplary and reflective of the cosmic stature of his thought. But most importantly, Sankara was a spirit of free enquiry, whose works are a call to the heart as much as a call to the mind.