Scientific Innovation

Historians have called the Hellenistic period the golden age of ancient science. Scientific innovation flourished because Alexander’s expedition had encouraged curiosity and increased knowledge about the world’s extent and diversity, royal families supported scientists financially, and the concentration of scientists in Alexandria promoted the exchange of ideas.

The greatest advances in scientific knowledge came in geometry and mathematics. Euclid, who taught at Alexandria around 300 B.C.E., made revolutionary discoveries in analyzing two- and three-dimensional space. Euclidean geometry is still useful. Archimedes of Syracuse (287–212 B.C.E.) calculated the approximate value of pi and invented a way to manipulate very large numbers. He also invented hydrostatics (the science of the equilibrium of fluid systems) and mechanical devices, such as a screw for lifting water to a higher elevation and cranes to disable enemy warships. Archimedes’ shout of delight when he solved a problem while soaking in his bathtub has been immortalized in the expression Eureka! meaning “I have found it!”

Advances in Hellenistic mathematics energized other fields that required complex computation. Early in the third century B.C.E., Aristarchus was the first to propose the correct model of the solar system: the earth revolving around the sun. Later astronomers rejected Aristarchus’s heliocentric model in favor of the traditional geocentric one (with the earth at the center) because conclusions drawn from his calculations of the earth’s orbit failed to correspond to the observed positions of celestial objects. Aristarchus had assumed a circular orbit instead of an elliptical one, an assumption not corrected until much later. Eratosthenes (c. 275–194 B.C.E.) pioneered mathematical geography. He calculated the circumference of the earth with astonishing accuracy by measuring the length of the shadows cast by widely separated but identically tall structures. Together, these researchers gave Western scientific thought an important start toward its fundamental procedure of reconciling theory with observed data through measurement and experimentation.

Hellenistic science and medicine made gains even though no technology existed to measure very small amounts of time or matter. The science of the age was as quantitative as it could be, given these limitations. Ctesibius invented pneumatics by creating machines operated by air pressure. He also built a working water pump, an organ powered by water, and the first accurate water clock. Hero of Alexandria also built a rotating sphere powered by steam. As in most of Hellenistic science, these inventions did not lead to usable applications in daily life. The scientists and their royal patrons were more interested in new theoretical discoveries than in practical results, and the technology did not exist to produce the pipes, fittings, and screws needed to build metal machines.

Hellenistic science produced impressive military technology, such as more powerful catapults and huge siege towers on wheels. The most famous large-scale application of technology for nonmilitary purposes was the construction of the Pharos, a lighthouse three hundred feet tall, for the harbor at Alexandria. Using polished metal mirrors to reflect the light from a large bonfire, the Pharos shone many miles out over the sea. Awestruck sailors called it one of the wonders of the world.

Medicine also benefited from the Hellenistic quest for new knowledge. Increased contact between Greeks and people of the Near East made Mesopotamian and Egyptian medical knowledge better known in the West and promoted research on what made people ill. Hellenistic medical researchers discovered the value of measuring the pulse in diagnosing illness and studied anatomy by dissecting human corpses. It was rumored that they also dissected condemned criminals while they were still alive; they had access to these subjects because the king authorized the research. Some of the terms then invented are still used, such as diastolic and systolic for blood pressure. Other Hellenistic advances in anatomy included the discovery of the nerves and nervous system.