The first scientists weren’t called scientists at all. The word “scientist” didn’t exist until 1833, when the English polymath William Whewell coined it in response to a challenge from the poet Samuel Taylor Coleridge. Before that, people who studied the natural world were known as “natural philosophers.” But the practice of observing nature, recording patterns, and proposing explanations based on evidence rather than myth stretches back thousands of years, long before anyone in ancient Greece earned the title we now associate with the tradition.
Babylonian Astronomers: Science Before the Greeks
The earliest recorded scientific observations come from Mesopotamia. Babylonian astronomers were tracking the movements of Venus as early as the reign of King Ammisaduqa, around 1700 BCE, recording their findings on clay tablets. By the eighth century BCE, they maintained detailed stellar catalogues and systematic records of solar eclipses. In 747 BCE, during the reign of King Nabonassar, Babylonian astronomers recognized that 235 lunar months are nearly identical to 19 solar years, a cycle so accurate it remained useful for calendar-making for centuries. The first solar eclipse they successfully predicted occurred on June 15, 763 BCE.
Even earlier, a clay tablet from the ancient city of Ugarit (in modern-day Syria) contains what is likely the oldest eclipse record in existence, most likely describing the eclipse of March 5, 1223 BCE. These weren’t casual observations. Babylonian astronomers kept what they called “astronomical diaries” continuously from the seventh century BCE through the first century BCE, making them arguably the longest-running scientific record-keeping project in history.
Enheduanna: A Priestess Who Studied the Stars
One remarkable early figure is Enheduanna, who served as High Priestess, Chief Astronomer, and Chief Civil Authority of Sumer around 2300 BCE. Based at the temple-city of Ur, she made what may be the first recorded correction of a major astronomical error. The prevailing view at the time held that the “Morning Star” and “Evening Star” were two separate celestial bodies. During a solar eclipse, Enheduanna observed Venus at one horizon, then at its highest point in the sky, and then at the opposite horizon. She concluded they were a single object. This kind of reasoning, using direct observation to overturn a traditional belief, is a hallmark of scientific thinking.
Ancient Egypt’s Clinical Approach
The ancient Egyptians practiced something strikingly close to clinical science in medicine. The Edwin Smith Surgical Papyrus, dating to around 1600 BCE (and likely copied from texts several centuries older), contains a collection of surgical cases that follow a consistent structure: observation, diagnosis, treatment, and prognosis for each condition. This systematic case-by-case approach mirrors the logic of the modern scientific method, though it was intertwined with the mysticism and religious practices that were central to Egyptian healing. The papyrus also reveals early medical specialization, suggesting that some Egyptian physicians focused on specific areas of the body.
India’s Mathematical Foundations
In ancient India, the Sulba Sutras laid out geometric principles used to design ritual altars. The Baudhayana Sulba Sutra, estimated to date from around 800 BCE or earlier, is considered the world’s oldest known mathematical text. It states what we now call the Pythagorean theorem: the square on the diagonal of a rectangle equals the sum of the squares on its two sides. The text lists integer triples satisfying this relationship, including (3, 4, 5), (5, 12, 13), and (8, 15, 17), centuries before Pythagoras was born.
Vedic scholars also produced remarkably precise approximations. Their value for the square root of 2, expressed as 577/408, is accurate to five decimal places. The Rigveda references a 360-day year divided into 12 segments, likely describing the zodiacal belt, and a “wheel of time” with 720 days and nights. These weren’t idle musings. They reflected careful measurement and calculation applied to real astronomical and architectural problems.
Thales of Miletus: The Greek Starting Point
When people ask “who was the first scientist,” the name that comes up most often is Thales of Miletus, a Greek thinker who lived around 624 to 546 BCE. Aristotle identified Thales as the first person to investigate the basic principles of matter and the originating substances of the natural world. What made Thales different from the Babylonian and Egyptian observers who came before him wasn’t necessarily better data. It was a shift in the kind of explanation he offered.
Thales proposed that water was the fundamental substance underlying all of nature. The earth, he argued, floats on water the way wood floats, and earthquakes happen when that water becomes turbulent. He suggested that even the fire of the sun and stars is nourished by evaporation. These ideas were wrong, but their significance lies in what they left out: gods. Thales replaced mythological explanations with materialistic ones, proposing that natural events have natural causes. He founded the Milesian school of natural philosophy and is credited with initiating the first Western enlightenment. In the words of later Greek writers, he “supplanted myth in his explanations of the behaviour of natural phenomena.”
Aristotle: Observation as Method
Aristotle, working in the fourth century BCE, pushed the practice further by grounding his theories in extensive physical observation. His biological works reveal someone who consulted beekeepers, fishermen, and sponge divers, and who performed (or supervised) dissections on a wide variety of animals. He developed a careful system for cataloguing similarities and differences across species. His characteristic reasoning pattern, “as many animals as have blood, all have a heart,” was designed to record universal correlations while leaving room for exceptions not yet encountered. This open-ended approach to classification was, as scholars have noted, a brilliant methodological innovation. Aristotle wasn’t just collecting facts. He was building a framework for how to collect facts.
Ibn al-Haytham and the Experimental Method
The person most often credited with establishing the modern experimental method is Ibn al-Haytham, an Arab scholar who worked around 1000 CE. His book on optics, “Kitab al-Manazir,” changed the field by grounding it in controlled experiments rather than abstract theories. He developed a repeating cycle of observation, hypothesis, experimentation, and independent verification that closely mirrors what we now teach as the scientific method.
One of his most important findings overturned a belief that had persisted since Euclid and Ptolemy: that the eyes emit light to see objects. Ibn al-Haytham demonstrated through systematic, repeatable experiments that the eyes receive light reflected from objects instead. The majority of historians of science regard him as the pioneer of the modern scientific method, the person who established experiments as the standard of proof.
Why There’s No Single Answer
The question of who the “first scientists” were depends on what you mean by science. If science means recording careful observations of nature and finding patterns, the Babylonian astronomers were doing it by 1700 BCE. If it means proposing natural rather than supernatural explanations, Thales gets the credit around 600 BCE. If it means controlled, repeatable experiments designed to test a hypothesis, Ibn al-Haytham is the strongest candidate around 1000 CE. And if you insist on the actual word “scientist,” nobody qualified until William Whewell invented the term in 1833, because before that the only options in English were “natural philosopher” and “man of science.”
What’s clear is that scientific thinking didn’t emerge in a single moment or from a single culture. It developed gradually across Mesopotamia, Egypt, India, Greece, and the Islamic world, with each tradition contributing methods and insights that later traditions built upon.