Last year, a professor at the Indian Science Congress, in Mumbai, claimed that India possessed airplanes seven thousand years ago. He isn’t alone in such beliefs. When a certain swathe of India’s population considers the country’s ancient past, it doesn’t see a country fragmented into kingdoms, savaged by caste divisions, and mired in poverty; rather, what’s envisioned is a vast, unified Hindu empire stretching from Kashmir to the Indian tip at Kanyakumari. This imagined entity brims with characters from Indian epics and spits out grand inventions that would put scientists in the twenty-first century to shame—not only airplanes but cars, plastic surgery, and stem-cell research. What these Indians see, in other words, is an India that was once greater than any other nation on earth, and which has since fallen into a cruddy, postcolonial despair. Muslim and British invaders, they insist, have sapped the subcontinent’s energies over the past millennium.

This is a major strand of the nativist philosophy espoused by Prime Minister Narendra Modi and the flotilla of parties and social organizations that escorted him to power, in 2014. It is, in the rippling and echoing way of world events, in step with archaic right-wing movements everywhere—Make India Great Again would be a suitable slogan—and it is untroubled by facts. In the past year, right-wing mobs have lynched and beaten Muslims and Dalits (the former untouchables, who have often refused to be co-opted by upper-caste-dominated Hindu nationalism) in Delhi, Haryana, Uttar Pradesh, Gujarat, Madhya Pradesh, and Jharkhand for allegedly eating beef, a crime that these nationalists cannot condone after a millennium of their religion’s supposed persecution. (Hinduism has always been the majority religion on the subcontinent.) Dormant laws in Indian states banning cow-slaughter and beef consumption are now being enforced. In January, a Dalit Ph.D. student at Hyderabad University hanged himself from the ceiling fan in his room after right-wing groups bore down on him for his activism. Elsewhere, emboldened nationalist groups have intimidated fiction writers, scholars, and publishers into silence for wounding religious sentiments. Student protests are branded “anti-national” and slapped with sedition charges.

In India, right now, the past is violently alive, and it is being bandied about like a blunt instrument, striking down those who try to speak sense to the present or who try to point out that this past is itself a fiction.

One of the intellectuals involved in calling the right’s bluff is the Indian scholar Sunil Khilnani, who has just published an incisive work of popular history, “Incarnations: India in Fifty Lives.” Where the opposition is clamorous, the book is calm; where the opposition flexes its Vedic muscles, the book is undercutting, irreverent, and impish. It attempts to show, through prodigious but lightly worn scholarship, how complex and heterodox the Indian past was, and how it has been, and continues to be, constructed.

Khilnani begins with the Buddha, who lived around 500 B.C.E., and is thus, Khilnani writes, the “first individual personality we can recognize in the subcontinent’s history,” as well as an apostle of neutrality and nonviolence. The Buddha’s religion has receded in India, except as a balm to the Dalits, who escaped into it, and as a self-help tool for a sliver of the upper classes, who have embraced it the way that some people in the West do. Buddha prefigures many of the themes in the book. A sheltered man, he is moved by his first encounter with suffering, and leaves behind his wealthy family to wander India in the thrall of slowly budding new ideas. He is serene and centered amid violence. He is open-minded and against sects in a Brahmin-dominated society. He calls for a total reinvention of Hinduism—one that becomes its own religion. He critiques Hinduism in the usual way, characterizing it as overrun by ritual, with no path to personal enlightenment. To show a way out, he makes an example of his own life.

That example has been followed by many others in Indian history, consciously and unconsciously. The mystics and reformers Mahavira, Adi Shankara, Basava, Kabir, Guru Nanak, Jyotirao Phule, Vivekananda, and Gandhi all left home at a young age to embark on radical self-experiments. Mahavira founded Jainism; Shankara came up with the monist philosophy known as Advaita Vedanta; Guru Nanak inaugurated Sikhism. Each embodied a critique of Indian society and showed a way forward.

The social reformer Jyotirao Phule was born into the low “maali,” or gardener, caste in Poona (now Pune) around 1827. Educated at a Scottish missionary school and expelled from a friend’s wedding in his teens for being lower-caste, he began to see caste as an “an engine of suffering and exploitation.” In his early twenties, along with his wife, Savitribai, whom he had educated, he started a school for girls and untouchables at a time when both classes were considered beneath schooling. The couple was ostracized; Phule’s father kicked them out of his house. Savitribai was pelted daily with “mud and stones and garbage” on her walk to school, and had to keep a clean sari in her classroom to change into when she arrived. But this, Khilnani writes, only gave the couple “new freedom to be social provocateurs.” Phule went on to write searing Jacob Riis-like critiques of poverty and compared Brahmins to “slave masters” in the U.S. Later, when lower-caste movements gained steam in independent India, he was resurrected as a figurehead.

The monk Vivekananda, who popularized Hinduism in the West and is today misread as a proto-Hindu nationalist, had a similarly tortured trajectory. Born in 1863, he grew up in Calcutta in a privileged family and proceeded, over his lifetime, to study everything from the Vedas and the Upanishads to Freemasonry, Buddhist meditation, Hegel, and Thomas à Kempis’s “The Imitation of Christ.” He could, Khilnani writes, “recite pages from The Pickwick Papers as readily as sutras from Panini’s Ashtadhyayi.” But after he finished college, both his father and mentor died in quick succession. Suffering a breakdown, Vivekananda retreated to the banks of the Ganga to worship under the spiritualist Ramakrishna Paramhansa. He became a mendicant and began wandering India, and was “driven mad with mental agonies” over what he encountered: ritual, poverty, disease. Hinduism appeared to provide none of the salves it promised; instead, the caste system and child marriage had oppressed the majority of the population. Vivekananda began to turn away from mainstream Hindus and Brahmins and to pursue a purer form of Hinduism, one that was practical and geared toward social uplift. This was the revelation he supposedly had on the southernmost tip of India, one that, the next year, sent him sailing to the U.S. to spread the word about Hinduism at the Parliament of World’s Religions, in Chicago, in 1893. He crashed the Parliament and became one of its stars, earning the admiration of Henry and William James, who hung “on his utterances.” During pauses in his lecture circuit, he wrote the central text of modern yoga, “Raja Yoga.” But Vivekananda also kept his eyes open. He came back to India impressed with the “social openness, the comparative freedom of women, the ability of people to act collectively in their own interests,” and the relative dignity afforded to the lower classes in America. He began recommending the American habits of eating beef and bodybuilding to Indians. He was, in every way, a more liberal figure—well-read, curious, sensitive—than he is remembered as today.