Explain the difference between a priori and a posteriori.

Simply defined, a priori knowledge is knowledge that is gained from ones mind with full emancipation from the body and the senses. A posteriori knowledge is empirically drawn from experiences and senses. Those philosophers who are in favour of a priori suggest that there is a common human quality of reason, which completely facilitates our search for knowledge.  Those in favour of a posteriori tend to argue that without experience we can never know anything as without having something to perceive, what is there to be knowledgeable about and how can you be certain of anything unless you have physically witnessed it? Although to categorise philosophers as either empiricists or rationalists is an over simplification of matters, as a generalization of their works, Aristotle and Locke may be considered examples of empiricists whereas Plato and Descartes tend to lean towards the rationalist approach.