Epistemology

Epistemology deals with questions like "What is knowledge?" and "How do we know this?".

Etymology

"Epistemology" from "ἐπιστήμη" (knowledge) and "λόγος" (logos) was introduced into English by the Scottish philosopher James Frederick Ferrier.

Hellenistic views

The questions are as old as Philosophy itself, and the search for answers continues today.

Plato viewed knowledge as universal unchanging Ideas. One dialogue shows how all knowledge is inherent in everyone, whereas another says that that which must be there already to be able to percieve the world around him.

Aristotle tried to divide the types of knowledge, that which can be said of knowledge, into ten Categories. He further attempts to classify knowledge in books named physics, metaphysics, poetry (including theater), biology and zoology, logic, rhetoric, politics, government, and ethics. These areas of knowledge retain his names today.

Scientific revolution: reason and observation

The scientific revolution started with questioning old beliefs and the doubt lead to using reason and observation to gain new knowledge, instead of relying on the authority of Plato and Aristotle.

Reason and observation are important for knowledge to all philosophers, but are emphasis as to which was more important started the contention betweeen empiricm and rationalism.

Empiricims

Empiricists, like John Locke later stresses the importance of observation and experiments to obtain knowledge, even to the point of assuming that a new born child has a tabula rasa.

Ratonalism

Rationalists like René Descartes stress reason to arrive at knowledge since one can not always trust the senses.

Modern times

Immanuel Kant tries to resolve many issues, among them the contention between rationalism and empiricism. He uses twelve categories of knowledge and he argues, as Plato did before, that there has to be something in man already there to let observation into the mind. That which is already there before is a priori and gives a rational basis for handling the empirical knowledge, which is a posteriori knowledge. Reason corresponds to a priori and observation to a posteriori knowledge, thus reconciling rationalism and empiricism.