Many Ancient Greek influences can be found in modern culture. Most, if not all of the major religions were influenced in some way by Greek philosophy, particularly that of Plato, who posited a duality between the physical and the spiritual, or the world of the mind. Greek emphasis on balance and proportion still inform much of modern architecture and art. Greek or Greek-influenced thinkers were influential in many of the discoveries that form the foundations of modern mathematics, physical science, and other fields. Additionally, Greece was the source of many of the foundations of modern political theory, and indeed the study of politics itself.