Transcript: The study of knowledge is called epistemology. There are two fundamental routes or paths for the study of knowledge. One is the idea of empiricism which dates back to Aristotle 25 hundred years ago. In the empirical approach to the method of science everything is based on observation or data. You start by gathering data or observations and then proceed to make a hypothesis which leads to a prediction of other observable phenomena. Then you make more observations to test your hypothesis and adjust it as needed. In this view of the universe and how science works everything is based on observations. The alternative view is called rationalism, and it probably dates back also 25 hundred years to the mathematician Pythagoras. In the rationalists view of how science works you start by conceiving mentally of models or ways that the world works. So you start with a mental framework, and then you proceed to derive observational tests of that mental framework and you go from there. Clearly science as it’s actually practiced by scientists imbeds elements of both ways of doing science. Science cannot proceed without observation, and clearly scientists have formulated important and sophisticated mathematical models of how the universe works. Both are required if science is to move forward.