Thinkers Timeline

The Buddha was a teacher who lived in northern India around 2,500 years ago. His personal name was Siddhartha Gautama. 'Buddha' is a title. It means 'the awakened one' or 'the one who is awake'. Most scholars now think he lived from about 480 to 400 BCE, though older tradition gives earlier dates. He was born a prince of the Shakya clan, in what is now southern Nepal. The traditional story says his father tried to keep him from seeing suffering. The young prince lived in palaces full of beauty and pleasure. He married and had a son. Then, around the age of 29, he saw four things outside the palace: an old man, a sick man, a dead man, and a wandering holy man. These sights changed him. He left his family and his comfortable life. He spent six years living as a wanderer. He tried very strict self-denial, eating almost nothing. This nearly killed him. He gave up extreme practices. He sat under a tree at a place now called Bodh Gaya and meditated. He said he reached awakening, a deep understanding of how suffering works and how to end it. He spent the next 45 years teaching across northern India. He gathered followers and built a community of monks and nuns. He died around the age of 80. His teachings became one of the world's major religions and philosophies.

Nagarjuna (approximately 150-250 CE) was an Indian Buddhist philosopher, widely considered one of the most important and influential thinkers in the entire history of Asian philosophy. He was born in South India, probably in what is now Andhra Pradesh, and became a Buddhist monk and teacher. He is the founder of the Madhyamaka school of Buddhist philosophy, which became one of the dominant schools of Buddhist thought across India, Tibet, China, Korea, Japan, and Southeast Asia. Very little is known about his life as a historical person: later tradition attributed extraordinary feats and a legendary biography to him, making it difficult to separate fact from story. What we do have are his philosophical texts, above all the Mulamadhyamakakarika, the Fundamental Verses on the Middle Way, a short but extraordinarily dense philosophical work in verse form that argues for one of the most radical positions in the history of philosophy: that nothing whatsoever has fixed, independent existence. He died sometime in the second or third century CE, but his ideas have continued to shape Buddhist philosophy and practice across Asia for nearly two thousand years.

Pāṇini was an ancient Indian grammarian whose work on the Sanskrit language is often described as one of the greatest intellectual achievements of the ancient world. Almost nothing is known about him as a person. Scholars usually place him in the fifth or fourth century BCE, though some argue for earlier dates. He is said to have come from Shalatula, a town in the region of Gandhara, which is now in north-west Pakistan near the Afghan border. This area was on the north-western edge of the Indian cultural world and close to routes that connected India with Persia, Central Asia, and the Mediterranean. A few traditional stories about his life exist, but they are legends rather than reliable history. What survives and matters is his book. It is called the Ashtadhyayi, which means the Eight Chapters, because it is divided into eight books. The book contains around four thousand short rules called sutras. These rules together describe the grammar of the Sanskrit language of his time with extraordinary completeness and precision. The sutras are not written for beginners. They are compressed to the point of being almost impossible to understand without training. Each sutra uses only the smallest number of syllables needed to state a rule. The rules also refer to each other in complex ways — later rules assume earlier rules, some rules override others in specific conditions, abbreviations are used to save space. Reading the Ashtadhyayi properly requires first learning Pāṇini's own system of notation. Later Indian grammarians spent the next two thousand years writing commentaries that explained his work. The most important of these was by Patanjali in the second century BCE. Modern scholars have continued to study the Ashtadhyayi and have discovered that it anticipates many features of modern linguistic and computer science theory. Pāṇini's grammar is one of the oldest works in any field that still rewards close study today.

Adi Shankara (traditionally 788-820, though some scholars propose earlier dates) was an Indian philosopher and theologian whose consolidation of the Advaita Vedanta school shaped Hindu thought more decisively than any other single figure in the tradition. He was born in Kaladi in what is now Kerala, in southern India, into a Nambudiri Brahmin family. Traditional biographies describe his father as dying when he was young and his mother as devout and learned. He is said to have become a renunciate at eight — a striking step taken, according to tradition, with his mother's reluctant consent. He studied under Govinda Bhagavatpada, himself a student of Gaudapada, whose commentary on the Mandukya Upanishad provided Shankara with much of his philosophical starting point. Shankara spent his short life travelling across the Indian subcontinent, debating rival philosophers, establishing monasteries, and writing prolifically. He founded four major monastic centres (mathas) at the cardinal points of India — at Sringeri in the south, Puri in the east, Dwarka in the west, and Jyotirmath in the north — each to be led by a lineage-holder called a Shankaracharya. This institutional network remains active today. His writing output was extraordinary for someone who lived only thirty-two years by traditional reckoning. His commentaries on the three foundational texts of Vedanta — the Upanishads (particularly the ten principal Upanishads), the Bhagavad Gita, and the Brahma Sutras — are the authoritative statements of Advaita Vedanta. He also wrote shorter philosophical works including the Upadesasahasri (A Thousand Teachings), and devotional hymns including the Bhaja Govindam, that remain widely recited. Traditional accounts place his death at Kedarnath in the Himalayas. The dating of his life has been contested — some scholars propose sixth- or seventh-century dates based on textual evidence — but the ninth century remains the conventional position.

Mirabai was a sixteenth-century Indian poet and saint. She is one of the most loved figures in the bhakti movement, a Hindu devotional tradition that swept across India for many centuries. She was born around 1498 in Kudki, a village in present-day Rajasthan in north-west India. Her family, the Rathore Rajputs, were a royal warrior clan. Her mother died when she was young. According to tradition, Mirabai was given a small image of the god Krishna by a holy man during her childhood. She held on to it, and her devotion to Krishna grew. She came to see him as her divine husband. In 1516, when she was about 18, she was married to Bhoj Raj, the crown prince of the neighbouring Mewar kingdom. He was wounded in battle and died in 1521. Mirabai refused to commit sati, the practice of a widow burning herself on her husband's funeral pyre, which was expected of Rajput princesses. This refusal began a long conflict with her in-laws. Legends say her in-laws made several attempts to kill her: poison disguised as nectar, a snake in a basket of flowers, a bed of nails. Each time, she survived. Whether these stories are literal history or symbols of her spiritual protection, they show that she lived under real threat. She eventually left palace life. She wandered to Vrindavan, Krishna's mythical home, and to Dwarka in Gujarat. She sang her songs in temples and public places. She is believed to have died around 1547. Hundreds of devotional songs are attributed to her, though most were probably composed later in her tradition.

Savitribai Phule (1831-1897) was an Indian teacher, poet, and social reformer who is widely recognised as the first female teacher of India and one of the founders of girls' education in the country. She was born in Naigaon, a small village in what is now the state of Maharashtra. Her family were farmers from the Mali caste — a community that faced social restrictions in the caste system but was not among the most oppressed. She was married at the age of nine to Jyotirao Phule, who was thirteen. This was normal for the time, when child marriage was widespread. What happened next was not normal. Jyotirao recognised that his young wife was intelligent and deserved an education, which was denied to almost all women and all lower-caste people in the India of that period. He began teaching her at home. She was a quick student. Within a few years she was literate in Marathi and beginning to read English. In 1848, when Savitribai was seventeen and Jyotirao was twenty-one, they opened a school for girls in Pune. This was an extraordinary act. Girls of any caste were not supposed to be educated. Lower-caste children were particularly forbidden from learning. Savitribai was the first woman in India to teach in a formal school. On her way to teach each day, people threw stones and cow dung at her. She reportedly carried a second sari so she could change when she arrived at school. The couple later opened schools for Dalit children (the community then called untouchables), a well for drinking water open to all castes at a time when lower-caste people were denied clean water, and a home for pregnant women who had been abandoned. Savitribai wrote poetry in Marathi. Her collections Kavya Phule (Poetry's Flowers, 1854) and Bavan Kashi Subodh Ratnakar (1891) are considered among the earliest examples of modern Marathi poetry. She adopted the son of a widow she had helped and raised him as her own. After Jyotirao's death in 1890, she continued their work alone. She died in 1897 while caring for patients during a plague epidemic in Pune; she caught the disease from a boy whose life she had tried to save.

Rabindranath Tagore (1861-1941) was an Indian poet, philosopher, and educator from Bengal, a region now divided between India and Bangladesh. He was born into a wealthy and intellectually active family in Kolkata and grew up surrounded by art, music, literature, and philosophical discussion. He began writing poetry as a child and became one of the most celebrated writers in the Bengali language, producing poetry, short stories, novels, plays, songs, and essays throughout his long life. In 1913 he became the first non-European to receive the Nobel Prize in Literature. He also composed the national anthems of both India and Bangladesh, the only person to have composed the national anthem of two countries. But he was not only a writer. He founded an experimental school at Santiniketan in 1901 that was built on his philosophy of education: learning through nature, creativity, and joy rather than through rigid discipline and examination. He was deeply engaged with political questions including Indian independence, but he was also a sharp critic of nationalism, which he saw as a dangerous force. He travelled widely across Europe, Asia, and the Americas and believed deeply in the possibility of genuine dialogue between cultures.

Srinivasa Ramanujan was an Indian mathematician born in 1887 in Erode, a small town in Tamil Nadu. His family was poor but educated. His father was a clerk and his mother was a devout Hindu. From a young age, he loved numbers. By the age of twelve, he was working through advanced mathematics books on his own. He had very little formal mathematical training. He failed his college exams because he spent all his time on mathematics and neglected other subjects. He lost his scholarship. He worked as a clerk in Madras and did mathematics in every spare moment. He filled notebooks with thousands of results, many of which were new and surprising. In 1913, he wrote a letter to G. H. Hardy, a leading mathematician at Cambridge University in England. The letter contained strange and beautiful formulas. Hardy was amazed. He invited Ramanujan to Cambridge in 1914. The two men worked together for five years. Ramanujan produced brilliant results on number theory, infinite series, and continued fractions. Life in England was hard. The climate was cold. The food was wrong for his vegetarian diet. He became very ill, possibly with tuberculosis or a parasitic infection. He returned to India in 1919 and died in 1920, aged only 32. His notebooks are still being studied today.

B.R. Ambedkar (1891-1956) was an Indian jurist, economist, social reformer, and philosopher. His full name was Bhimrao Ramji Ambedkar. He was born into a Dalit family, the community then called Untouchables, who occupied the lowest position in India's caste hierarchy and were subjected to severe discrimination, exclusion, and violence. Despite the enormous obstacles placed in front of him by the caste system, Ambedkar became one of the most educated people in India of his generation, earning doctorates from Columbia University in New York and the London School of Economics. He spent his life fighting against caste as a system of oppression and arguing for the full rights and dignity of Dalit people. He was the chief architect of the Indian Constitution, which he designed to protect the rights of all citizens and to prohibit caste discrimination. In the last year of his life, he converted to Buddhism along with hundreds of thousands of his followers, an act he understood as both a spiritual choice and a rejection of the Hindu caste system. He died in 1956, just weeks after completing his final manuscript.

Ravi Shankar was an Indian musician. He played the sitar, a long-necked string instrument from northern India. He is the most famous Indian classical musician of the 20th century. He was born in 1920 in the city of Varanasi (also called Banaras), in northern India. He came from a Bengali Brahmin family. His father was a lawyer and scholar who left the family when Ravi was young. His older brother Uday Shankar was a famous dancer who toured the world with an Indian dance company. As a boy, Ravi joined his brother's troupe. He travelled across Europe and America as a young dancer and musician. He met many Western artists in this period. At 18, he made a serious decision. He left his brother's company and went to study music seriously with a great teacher named Allauddin Khan in central India. He spent seven years in Khan's home, training intensively in the strict Indian classical tradition. This kind of long apprenticeship was traditional. The teacher was almost a parent. Ravi later married Khan's daughter, Annapurna Devi, who was also a brilliant musician. From the 1950s onwards, his career grew rapidly. He performed across India, then in Europe and America. In the 1960s he became famous in the West, partly because of his friendship with George Harrison of the Beatles. He continued performing into his nineties. He had a complex personal life, with several partners and four children, including the musicians Anoushka Shankar and Norah Jones. He died in San Diego in 2012, aged 92.

Amartya Sen (born 1933) is an Indian economist and philosopher. He was born in West Bengal, India, and grew up during a period of great upheaval: as a child he witnessed the Bengal famine of 1943, in which around three million people died of hunger. This experience shaped his life's work. He studied economics in India and then at Cambridge University in England, where he later became a professor. He has also taught at Harvard University in the United States, where he has spent much of his career. In 1998 he received the Nobel Prize in Economics for his work on welfare economics, poverty, and inequality. He is best known outside economics for two connected contributions: the capabilities approach, a new way of measuring human development and wellbeing, and his analysis of famine, which showed that famines are not caused by a shortage of food but by political failures that leave some people unable to afford the food that exists. He has also written important books on democracy, justice, identity, and the relationship between freedom and development.

Coimbatore Krishnarao Prahalad (1941-2010) was an Indian-American management scholar whose ideas about corporate strategy, core competence, and the business opportunity at the bottom of the pyramid transformed how companies and development thinkers approached both strategy and poverty. He was born in Coimbatore, in Tamil Nadu, the son of a judge and a civil servant. He studied physics at Loyola College, Madras, and worked for four years in an Indian branch of Union Carbide, the American chemical company, before entering the Indian Institute of Management in Ahmedabad. In 1972 he travelled to the United States for doctoral work at Harvard Business School, completing his thesis in 1975. He joined the faculty of the University of Michigan's Ross School of Business in 1977 and remained there for the rest of his career. His 1990 Harvard Business Review article with Gary Hamel, The Core Competence of the Corporation, became one of the most-cited business articles ever written and reshaped strategic thinking through the 1990s. His later work took him in a different direction. His 2002 article and 2004 book The Fortune at the Bottom of the Pyramid argued that the world's poorest four billion people represented not only a moral claim on international attention but also a significant market that could be served profitably if products and business models were designed appropriately. The book reached business schools, development agencies, and corporations. He continued publishing influential work until his death, wrote regularly for Indian newspapers on the country's development, and mentored a generation of scholars and practitioners. He died in San Diego in 2010 at the age of sixty-eight.

Vandana Shiva (born 1952) is an Indian physicist, environmental activist, and philosopher. She was born in Dehradun in the foothills of the Himalayas, into a family with deep connections to forests and farming. She studied physics at university and completed a doctorate in the philosophy of science at the University of Western Ontario in Canada. She then returned to India and made a decision that changed the direction of her life: she left academic science to work with the Chipko movement, a grassroots movement in which Indian village women embraced trees to prevent them being cut down by commercial loggers. This experience convinced her that the most important environmental battles were being fought not in laboratories or conference rooms but in the fields and forests where ordinary people, particularly women, lived and worked. She founded the Research Foundation for Science, Technology and Ecology and later Navdanya, an organisation that works to protect seed diversity and support small farmers. She has received the Alternative Nobel Prize and many other awards and is one of the most recognised voices in global debates about food, farming, and the natural world.

Indra Krishnamurthy Nooyi (born 1955) is an Indian-American businesswoman and former chief executive of PepsiCo, one of the world's largest food and beverage companies. She was born in Madras (now Chennai) to a Tamil Brahmin family and grew up in a middle-class household where education was valued intensely. Her mother regularly asked her daughters at dinner to explain what they would do as president or prime minister, a practice Nooyi later credited with shaping her ambition. She studied physics, chemistry, and mathematics at Madras Christian College, earned an MBA from the Indian Institute of Management in Calcutta, and won a scholarship to Yale School of Management, where she completed a second master's degree in 1980. She worked at the Boston Consulting Group, Motorola, and Asea Brown Boveri before joining PepsiCo in 1994. She rose through corporate strategy and finance roles, led the spin-off of PepsiCo's restaurant businesses (Pizza Hut, KFC, Taco Bell) into Yum Brands, and led the acquisition of Tropicana and Quaker Oats. She became chief financial officer in 2001, president and CFO in 2006, and chief executive officer and chairman in 2006 — the first woman of colour to lead a Fortune 50 company. During her twelve years as CEO, PepsiCo's revenue grew from forty-four to sixty-four billion dollars. She led a strategic reorientation she called Performance with Purpose, shifting the company's portfolio toward healthier products while maintaining profitability. She retired as CEO in 2018 and as chairman in 2019. She has since served on the boards of Amazon, the International Cricket Council, and the World Economic Forum, co-led a New York State commission on reopening during the Covid pandemic, and published her 2021 memoir My Life in Full. She lives in Connecticut with her husband, Raj, and their two daughters.