The word ‘philosopher’ is Greek in origin and means ‘a lover of wisdom’. The famous Greek philosophers, such as Plato and Aristotle, did not trouble themselves overmuch about fine and hair-splitting distinctions concerning the limits of the philosopher’s role (although Plato went to some lengths to distinguish himself, the real philosopher, from various charlatans; the charlatans, in his view, were those whose concern was simply to win an argument by any means to hand). As far as they were concerned, a philosopher was just somebody who was interested in acquiring knowledge and pursuing truth in any sphere. Aristotle, for instance, in our terminology, was a political theorist, an antiquarian, a moral philosopher and a biologist. In his own terminology he was a philosopher, whether he was indulging his antiquarian interests or involved in biological research. For Plato and Aristotle there was no fumbling doubt about what they were professionally entitled to do, or the proper limits of philosophical inquiry. They were looking for answers to every conceivable question that could be raised, they were seeking to explain and understand the world in all its aspects, and ultimately they aimed to lay down the plan for the Good Life for mankind.