Empiricism is an epistemological theory (or, a theory of how we know stuff) that is primarily concerned with sensory experience. Empiricists believe that all knowledge comes from our senses, and from actually physically experiencing the world. They DO NOT think there are any innate ideas, ideas that are held in the mind a priori, or independently of experience. Empiricism is more or less the direct contrast of rationalism: the rationalists (like Descartes, who I talked about last week) believe that all knowledge comes from reason alone. They don’t trust sensory experience because our senses can be deceived; but pure reason cannot be.