What is 'reason'? Using logic and evidence to form thoughts and solve problems. What's a THEORY? An explanation for how or why something happens.. Who said that the universe revolves around the Earth? Ptolemy. The idea of a universe that revolves around the Earth is called: geocentric. The idea that the solar system revolves around the sun is called: heliocentric. What DOES our solar system revolve around? the sun. The ancient Greeks and Romans had ideas about how the universe worked, but they didn't: perform experiments. On what did ancient Greeks and Romans base their ideas of how the universe worked: common sense. How did that work out for the Greeks and Romans, just trying to use common sense? It led to a lot of incorrect ideas.. In the 1500s, Europeans figured out that scientists had to use mathematics and experiments to make advances. This realization was called: The Scientific Revolution.. Scientist Isaac Newton wrote a book called 'Principia,' which advanced ideas about: gravity. For a long time, we didn't know much about how the human body worked, because many cultures: forbade scientists to dissect human beings. An orderly way of collecting and analyzing evidence... the Scientific Method