Ancient Greecephilosophy in Ancient Greece accompanied its literary development. Greek learning had a profound influence on Western and Middle Eastern civilizations. The works of Socrates, Plato, Aristotle, and other Greek philosophers profoundly influenced Classical thought, the Islamic Golden Age, and the Renaissance.
In medicine, doctors still refer to the Hippocratic oath, instituted by Hippocrates, regarded as foremost in laying the foundations of medicine as a science. Galen built on Hippocrates' theory of the four humours, and his writings became the foundation of medicine in Europe and the Middle East for centuries. The physicians Herophilos and Paulus Aegineta were pioneers in the study of anatomy, while Pedanius Dioscorides wrote an extensive treatise on the practice of pharmacology.
The period of Classical Greece (from 800BC until the rise of Macedon, a Greek state in the north) is that most often associated with Greek advances in science. Thales of Miletus is regarded by many as the father of science; he was the first of the ancient philosophers to seek to explain the physical world in terms of natural rather than supernatural causes. Pythagoras was a mathematician often described as the "father of numbers"; it is believed that he had the pioneering insight into the numerical ratios that determine the musical scale, and the Pythagorean theorem is commonly attributed to him. Diophantus of Alexandria, in turn, was the "father of algebra". Many parts of modern geometry are based on the work of Euclid, while Eratosthenes was one of the first scientific geographers, calculating the circumference of the earth and conceiving the first maps based on scientific principles.
The Hellenistic period, following Alexander's conquests, continued and built upon this knowledge. Hipparchus is considered the pre-eminent astronomical observer of the ancient world, and was probably the first to develop an accurate method for the prediction of solar eclipse, while Aristarchus of Samos was the first known astronomer to propose a heliocentric model of the solar system, though the geocentric model of Ptolemy was more commonly accepted until the seventeenth century. Ptolemy also contributed substantially to cartography and to the science of optics. For his part Archimedes was the first to calculate the value of π and a geometric series, and also the earliest known mathematical physicist discovering the law of buoyancy, as well as conceiving the irrigation device known as Archimedes' screw.