Lesson 21: Ancient Indian Science, Mathematics and Medicine

Long before modern laboratories, Indian scholars developed a decimal number system, calculated the value of pi, described the rotation of the earth, and compiled surgical and medical treatises that were studied for a thousand years. Their work reached Europe not directly but through Persian and Arab scholars — which is why the numerals used around the world today are still called "Arabic" numerals, though they originated in India.

Mathematics: zero and place value

The decisive Indian contribution was place-value notation with a symbol for zero: the same digit means different values depending on its position, so that 505 is not 55. By the seventh century CE, Brahmagupta's Brahmasphutasiddhanta (628 CE) treated zero as a number in its own right, giving rules for adding, subtracting and multiplying with zero and with negative numbers. Earlier, Aryabhata's Aryabhatiya (499 CE) gave a value for pi correct to four decimal places (3.1416) and methods for square and cube roots. The Indian numeral system travelled west through Arab mathematicians — al-Khwarizmi's ninth-century works described Indian calculation — and from there into medieval Europe, where it gradually replaced Roman numerals for calculation.

Astronomy

Aryabhata (476–550 CE) argued that the apparent daily movement of the stars was caused by the rotation of the earth on its axis, and he calculated the length of the year with remarkable accuracy for his time. Later Indian astronomers, including Varahamihira (sixth century CE) and Bhaskara II (twelfth century CE), refined planetary models and eclipse prediction. Their astronomy was closely tied to calendar-making and to astrology, which modern readers should not confuse: the mathematical techniques were rigorous even when the purposes included astrological prediction.

Medicine: Ayurveda, Charaka and Sushruta

Indian medicine, known as Ayurveda ("knowledge of life"), is preserved in two great compendia. The Charaka Samhita deals mainly with internal medicine, diagnosis and pharmacology, while the Sushruta Samhita is famous for surgery, including descriptions of cataract couching, the repair of torn earlobes, and rhinoplasty — reconstructive surgery of the nose — using a flap of skin from the forehead, a technique later noted by British surgeons in India in the eighteenth century. The dating of both texts is uncertain: their core material is ancient, but they were compiled and revised over many centuries, from roughly the last centuries BCE into the early centuries CE. The lesson therefore does not assign them a single author's lifetime.

Indian medical theory rested on the balance of three humours (doshas) — a framework modern medicine does not accept — but its practice included careful observation, diet, herbal drugs, and surgical skill. The great monastic university of Nalanda (active roughly from the fifth to the twelfth centuries CE) taught medicine alongside Buddhist philosophy, logic and grammar, and drew students from China and Southeast Asia.

Why it matters

Ancient Indian science matters not because it anticipated every modern discovery — it did not — but because its mathematics, above all zero and place value, became part of the everyday toolkit of the whole world, and because its medical texts show a long tradition of systematic observation and surgery.