One of his most notable theories stated that the Earth was a large disk in an endless ocean and that earthquakes were the result when this boundless ocean shook the Earth. Before this theory was thought of, the people of Greece thought Poseidon caused earthquakes with his trident. Another one of his theories stated that water is the base element and that the world would become water again. He also hypothesized that when humans die, we return to water (The Ionian Philosophers, 12). Thales' reasoning for this theory was obtained by observing the world around him. Taking into account the amount of moisture that the Greek climate must have had, it could be seen as a plausible idea of how the world was formed or what it is predominantly composed of. However, Democritus disproved this theory and hypothesized that humans are made of atoms (The Ionian Philosophers, 17). He stated that atoms could not be created or destroyed. Another celebrated Greek in the field of natural philosophy was Pythagoras. He was a celebrated mathematician and early astronomer who, like Thales, studied in Egypt. His most famous work was the theorem named after himself. This theory, known as the Pythagorean Theorem, states that in order to find the hypotenuse of a right angle triangle you must add the squared result of each of the other two legs of the triangle (Violatti). This is still used in schools and geometry classes around the world to this day. It is arguably one of the most important mathematical theories. The Babylonians knew this thousands of years earlier, but Pythagoras was the first one to prove it (The Ionian Philosophers, 28). Another one of his accomplishments was his establishment of a school in Croton. Pythagoras founded this school with the help of his many followers (Violatti). They emphasized the ability to conduct themselves loyally and secretly when it came to this society. Another extremely notable philosopher was Aristotle.
