Inventions and Discoveries of Ancient Greek Scientists

Ancient Greek scientists have many inventions and discoveries attributed to them, rightly or wrongly, especially in the areas of astronomy, geography, and mathematics.

What We Owe to the Ancient Greeks in the Field of Science

Ptolemy's World, From The Atlas of Ancient and Classical Geography by Samuel Butler
Ptolemy's World, From The Atlas of Ancient and Classical Geography by Samuel Butler, Ernest Rhys, editor (Suffolk, 1907, repr. 1908). Public Domain. Courtesy of Maps of Asia Minor, the Caucasus, and Neighboring Lands

The Greeks developed philosophy as a way of understanding the world around them, without resorting to religion, myth, or magic. Early Greek philosophers, some influenced by nearby Babylonians and Egyptians, were also scientists who observed and studied the known world—the Earth, seas, and mountains, as well as the solar system, planetary motion, and astral phenomena.

Astronomy, which began with the organization of the stars into constellations, was used for practical purposes to fix the calendar. The Greeks:

  • Estimated the size of the Earth
  • Figured out how a pulley and levers work
  • Studied refracted and reflected light, as well as sound

In medicine, they:

  • Looked at how the organs work
  • Studied how a disease progresses
  • Learned to make inferences from observations

Their contributions in the field of mathematics went beyond the practical purposes of their neighbors.

Many of the ancient Greeks' discoveries and inventions are still used today, although some of their ideas have been overturned. At least one—the discovery that the sun is the center of the solar system—was ignored and then rediscovered.

The earliest philosophers are little more than legend, but this is a list of inventions and discoveries attributed through the ages to these thinkers, not an examination of how factual such attributions may be. 

Thales of Miletus (c. 620 - c. 546 B.C.)

Thales of Miletus
Thales of Miletus. Public Domain. Courtesy of Wikipedia.

Thales was a geometer, military engineer, astronomer, and logician. Probably influenced by Babylonians and Egyptians, Thales discovered the solstice and equinox and is credited with predicting a battle-stopping eclipse thought to be on 8 May 585 B.C. (the Battle of Halys between Medes and Lydians). He invented abstract geometry, including the notion that a circle is bisected by its diameter and that the base angles of isosceles triangles are equal.

Anaximander of Miletus (c. 611- c. 547 B.C.)

Anaximander From Raphael's The School of Athens.
Anaximander From Raphael's The School of Athens. Public Domain. Courtesy of Wikipedia.

The Greeks had a water clock or klepsydra, that kept track of short periods of time. Anaximander invented the gnomon on the sundial (although some say it came from the Babylonians), providing a way to keep track of time. He also created a map of the known world.

Pythagoras of Samos (sixth century)

Pythagoras, coin made under emperor Decius.
Pythagoras, coin made under emperor Decius. From Baumeister, Denkmäler des klassischen Altertums. 1888. Band III., Seite 1429. PD Courtesy of Wikipedia

Pythagoras realized that the land and sea are not static. Where now there's land, there once was sea and vice versa. Valleys are formed by running water and hills are eroded by water.

In music, he stretched the string to produce specific notes in octaves after having discovered the numerical relations between the notes of the scale.

In the field of astronomy, Pythagoras may have thought of the universe as rotating daily around an axis corresponding to the axis of the Earth. He may have thought of the sun, moon, planets, and even the earth as spheres. He is credited with being the first to realize the Morning Star and Evening Star were the same.

Presaging the heliocentric concept, a follower of Pythagoras, Philolaus, said the Earth revolved around the "central fire" of the universe.

Anaxagoras of Clazomenae (born about 499)

Anaxagoras. Public Domain. Courtesy of Wikipedia.

Anaxagoras made important contributions to astronomy. He saw valleys, mountains, and plains on the moon. He determined the cause of an eclipse—the moon coming between the sun and Earth or the Earth between the sun and the moon depending on whether it's a lunar or solar eclipse. He recognized that the planets Jupiter, Saturn, Venus, Mars, and Mercury move.

Hippocrates of Cos (c. 460-377 B.C.)

Hippocrates Statue
Hippocrates Statue. Flickr Creative Commons License by Epugachev

Previously, illness had been thought to be a punishment from the gods. Medical practitioners were priests of the god Asclepius (Asculapius). Hippocrates studied the human body and discovered there were scientific reasons for ailments. He told physicians to watch especially when fever peaked. He made diagnoses and prescribed simple treatments like diet, hygiene, and sleep.

Eudoxus of Knidos (c. 390–c.340 B.C.)

Eudoxus of Cnidus

Eudoxus improved the sundial (called an Arachne or spider) and made a map of the known stars. He also devised:

  • A theory of proportion, which allowed for irrational numbers
  • A concept of magnitude
  • A method for finding areas and volumes of curvilinear objects

Eudoxus used deductive mathematics to explain astronomical phenomena, turning astronomy into a science. He developed a model in which the earth is a fixed sphere inside a larger sphere of the fixed stars, which rotate around the earth in circular orbits.

Democritus of Abdera (460-370 B.C.)

Bust of Democritus
DEA / PEDICINI/Getty Images

Democritus realized the Milky Way was composed of millions of stars. He was the author of one of the earliest parapegmata tables of astronomical calculations. He is said to have written a geographical survey, as well. Democritus thought of the Earth as disk-shaped and slightly concave. It was also said that Democritus thought the sun was made of stone.

Aristotle (of Stagira) (384–322 B.C.)

Aristotle, from Scuola di Atene fresco, by Raphael Sanzio. 1510-11.
Aristotle, from Scuola di Atene fresco, by Raphael Sanzio. 1510-11. CC Flickr User Image Editor

Aristotle decided the Earth must be a globe. The concept of a sphere for the Earth appears in Plato's Phaedo, but Aristotle elaborates and estimates the size. 

Aristotle classified animals and is the father of zoology. He saw a chain of life running from the simple to more complex, from the plant through animals.

Theophrastus of Eresus - (c. 371–c. 287 B.C.)

Theophrast's Bust
PhilSigin/Getty Images

Theophrastus was the first botanist we know of. He described 500 different types of plants and divided them into trees herbs and shrubs.

Aristarchus of Samos (? 310-? 250 B.C.)

heliocentric hypothesis

Aristarchus is thought to be the original author of the heliocentric hypothesis. He believed the sun was immovable, like the fixed stars. He knew that day and night were caused by the Earth turning around on its axis. There were no instruments to verify his hypothesis, and evidence of the senses—that the Earth is stable—testified to the contrary. Many did not believe him. Even a millennium and a half later, Copernicus was afraid to reveal his heliocentric vision until he was dying. One person who did follow Aristarchus was the Babylonian Seleucos (fl. mid 2nd C B.C.).

Euclid of Alexandria (c. 325-265 B.C.)

Euclid, detail from "The School of Athens" painting by Raphael.
Euclid, detail from "The School of Athens" painting by Raphael. Public Domain. Courtesy of Wikipedia.

Euclid thought that light travels in straight lines or rays. He wrote a textbook on algebra, number theory, and geometry that is still relevant.

Archimedes of Syracuse (c.287-c.212 B.C.)

Archimedes' lever engraving from Mechanics Magazine published in London in 1824.
Archimedes' lever engraving from Mechanics Magazine published in London in 1824. PD Courtesy of Wikipedia.

Archimedes discovered the usefulness of the fulcrum and lever. He began the measurement of the specific gravity of objects. He is credited with having invented what is called the screw of Archimedes for pumping up water, as well as an engine to throw heavy stones at the enemy. A work attributed to Archimedes called The Sand-Reckoner, which Copernicus probably knew, contains a passage discussing Aristarchus' heliocentric theory.

Eratosthenes of Cyrene (c.276-194 B.C.)

Eratosthenes. PD Courtesy of Wikipedia.

Eratosthenes made a map of the world, described countries of Europe, Asia, and Libya, ​created the first parallel of latitude, and measured the circumference of the earth.

Hipparchus of Nicaea or Bithynia (c.190-c.120 B.C.)

Ptolemaic cosmology

Hipparchus produced a table of chords, an early trigonometric table, which leads some to call him the inventor of trigonometry. He cataloged 850 stars and accurately calculated when eclipses, both lunar and solar, would occur. Hipparchus is credited with inventing the astrolabe. He discovered the Precession of the Equinoxes and calculated its 25,771-year cycle.

Claudius Ptolemy of Alexandria (c. A.D. 90-168)

Section From The School of Athens, by Raphael. Zoroaster holding a globe talking with Ptolemy.
Section From The School of Athens, by Raphael (1509), showing Zoroaster holding a globe talking with Ptolemy. Public Domain. Courtesy of Wikipedia.

Ptolemy founded the Ptolemaic System of geocentric astronomy, which held for 1,400 years. Ptolemy wrote the Almagest, a work on astronomy that provides us with information on the work of earlier Greek astronomers. He drew maps with latitude and longitude and developed the science of optics. It is possible to overstate the influence of Ptolemy during much of next millennium because he wrote in Greek, while western scholars knew Latin.

Galen of Pergamum (born c. A.D. 129)

Galen. Public Domain. Courtesy of Wikipedia.

Galen (Aelius Galenus or Claudius Galenus) discovered nerves of sensation and motion and worked out a theory of medicine that doctors used for hundreds of years, based on Latin authors like Oribasius' inclusion of translations of Galen's Greek in their own treatises.