The Brahmo Samaj, the Hindu reform society founded in Calcutta by Rammohan Roy, worshipped one formless God and condemned the worship of images. It drew educated young Bengalis, and Narendranath Datta, the son of an attorney at the Calcutta High Court, joined it as a student. At the General Assembly's Institution, a Scottish mission college, he read Hume, Kant, Mill and Herbert Spencer, and the reading left him doubtful about religion of any kind. In 1881 he met Ramakrishna, a priest at the temple of the goddess Kali at Dakshineswar, north of the city, who worshipped her in an image and passed into states of ecstasy. The student was disturbed by the image worship and drawn by the man. It took him about four years to accept Ramakrishna as his teacher.
His father died in 1884 and left the family in debt and in lawsuits, and Narendranath gave up a plan to study law in England. After Ramakrishna's death in August 1886 he and a group of young disciples took monastic vows and lived together in a house at Baranagar. From 1890 he walked the length of India as a wandering monk, with a staff and a begging bowl, and what he saw of its poverty stayed in everything he later taught. He took the name Vivekananda in these years.
On 11 September 1893 he spoke at the World's Parliament of Religions in Chicago. In a paper eight days later he told the Parliament that Hinduism did not consist in believing a doctrine but in realising the truth, in experiencing it for oneself. The Parliament made him famous, and he stayed more than three years in the West, giving free classes in New York and lectures in London that a hired stenographer, Josiah Goodwin, took down. They became short books on four roads to freedom: work, devotion, knowledge, and the training of the mind. Each, he argued, leads to the same goal, and a person takes the one that fits their nature.
The goal is the one taught by Advaita Vedanta, the non-dual school: the real self of every person is the infinite itself. Vivekananda drew an ethical conclusion from it. If God is the self of every man and woman, then the poor and the hungry are God in the form nearest to hand, and serving them is worship, no less than prayer. He called this practical Vedanta, and he built an institution on it. On 1 May 1897, back in Calcutta, he founded the Ramakrishna Mission and required its monks to do seva, service to others, which he said Ramakrishna had intended. Its headquarters at Belur Math, on the Hooghly river, still trains monks, and the order runs centres in more than twenty countries outside India.
He died at Belur Math on 4 July 1902, at thirty-nine. Gandhi counted him among the reformers who had cut away the dead wood of Hindu tradition, and Aurobindo Ghose, the nationalist turned yogi, said he had heard Vivekananda's voice in a British jail. His appeal to experience became a rallying cry for Indian nationalism. Scholars have been less sure what he did to Vedanta. The German Indologist Paul Hacker called the modern Hinduism he taught Neo-Hinduism, as a term of reproach, holding it to be a new construction rather than a continuation of tradition. Others trace his reading of Advaita to its Western interpreters, Schopenhauer and his follower Paul Deussen, a German translator of the Upanishads, and ask whether Ramakrishna thought of himself as a Vedantin at all. Recent scholarship warns against overstating how new his teaching was. His birthday, 12 January, is kept in India as National Youth Day.