Abstract
We all know that there are many different kinds of “thing”; and what we mean, when we say something to that effect, is usually that things behave differently from one another, or react differently in different circumstances. Among the things to which these generalizations apply, we normally count both ourselves and other people. It was natural enough, therefore, for the philosophers to develop a theory of human nature as made up of a variety offacultiesandpowers(or “passions”). For this provides a convenient way of classifying and comparing our behaviours and reactions.