<P> Little evidence survives of how Ancient Indian cultures around the Indus River understood nature, but some of their perspectives may be reflected in the Vedas, a set of sacred Hindu texts . They reveal a conception of the universe as ever - expanding and constantly being recycled and reformed . Surgeons in the Ayurvedic tradition saw health and illness as a combination of three humors: wind, bile and phlegm . A healthy life was the result of a balance among these humors . In Ayurvedic thought, the body consisted of five elements: earth, water, fire, wind and empty space . Ayurvedic surgeons performed complex surgeries and developed a detailed understanding of human anatomy . </P> <P> Pre-Socratic philosophers in Ancient Greek culture brought natural philosophy a step closer to direct inquiry about cause and effect in nature between 600 and 400 BC, although an element of magic and mythology remained . Natural phenomena such as earthquakes and eclipses were explained increasingly in the context of nature itself instead of being attributed to angry gods . Thales of Miletus, an early philosopher who lived from 625 to 546 BC, explained earthquakes by theorizing that the world floated on water and that water was the fundamental element in nature . In the 5th century BC, Leucippus was an early exponent of atomism, the idea that the world is made up of fundamental indivisible particles . Pythagoras applied Greek innovations in mathematics to astronomy, and suggested that the earth was spherical . </P> <P> Later Socratic and Platonic thought focused on ethics, morals and art and did not attempt an investigation of the physical world; Plato criticized pre-Socratic thinkers as materialists and anti-religionists . Aristotle, however, a student of Plato who lived from 384 to 322 BC, paid closer attention to the natural world in his philosophy . In his History of Animals, he described the inner workings of 110 species, including the stingray, catfish and bee . He investigated chick embryos by breaking open eggs and observing them at various stages of development . Aristotle's works were influential through the 16th century, and he is considered to be the father of biology for his pioneering work in that science . He also presented philosophies about physics, nature and astronomy using inductive reasoning in his works Physics and Meteorology . </P> <P> While Aristotle considered natural philosophy more seriously than his predecessors, he approached it as a theoretical branch of science . Still, inspired by his work, Ancient Roman philosophers of the early 1st century AD, including Lucretius, Seneca and Pliny the Elder, wrote treatises that dealt with the rules of the natural world in varying degrees of depth . Many Ancient Roman Neoplatonists of the 3rd to the 6th centuries also adapted Aristotle's teachings on the physical world to a philosophy that emphasized spiritualism . Early medieval philosophers including Macrobius, Calcidius and Martianus Capella also examined the physical world, largely from a cosmological and cosmographical perspective, putting forth theories on the arrangement of celestial bodies and the heavens, which were posited as being composed of aether . </P>

How can we relate classification to the world around us