ABSTRACT
The theory of knowledge — otherwise known as epistemology — has been a central part of philosophy since the birth of the subject in ancient Greece. A starting-point in philosophical discussion of knowledge has always been its tremendous importance to people ; as Aristotle famously declares in the opening sentence of his Metaphysics , 'all men by nature desire to know'. The most immediate is why knowledge is so important to people; whether people are right to accord it such a status. In order to answer this question, it would help to know what knowledge is; what it is to possess knowledge. Questions about the nature of knowledge thus immediately raise further epistemological questions: about evidence, about rational confidence, about the justification of belief, about what one ought to believe, and so on.
