Aristotle emphasizes the central role of perception for knowledge acquisition in many of his writings. But how should these programmatic declarations be worked into an overall interpretation? Does perception provide the foundation on which all our knowledge can be grounded? Or does perception merely have the function of providing the intellect with elementary information? This study precisely works out which role perception plays in Aristotle's theory of knowledge acquisition. It shows that Aristotle defends a position that presents an interesting alternative to common views in the contemporary debate regarding the foundation of knowledge.