<p>René Descartes is famous as the philosopher who was prepared to doubt everything- even his own physical existence. Most people know that he said 'I think, therefore I am', even if they are not always sure what he really meant by it.<br><br> <br>Introducing Descartes explains what Descartes doubted, and why he is usually called the father of modern philosophy. It is a clear and accessible guide to all the puzzling questions he asked a...