Is knowledge possible? If so, what can we know and how do we come to know it? What degree of certainty does our knowledge enjoy? In these two powerful works, Descartes, the seventeenth-century philosopher considered to be the father of modern philosophy, outlines his philosophical method and then counters the sceptics of his time by insisting that certain knowledge can be had. He goes on to address the nature and extent of human knowledge, the distinction between mind and body, the existence of God, and the existence of external objects.