Political science, like the other social sciences, considers the behavior of
men in groups called social systems. There is a close relationship between political
science and certain other social sciences, like economics, social anthropology, and
sociology. Political science is a descriptive science. Empirical observations of what
actually happens in a given social situation involving power, authority or rule are
reported. Political philosophy, based on values, may also be studied, usually by
examining the works of outstanding philosophers of the past, like Plato, Aristotle,
Machiavelli, Marx, Mill, and others, or by evaluating particular philosophies.