Dream of Reason: A History of Western Philosophy from the Greeks to the Renaissance

A small but typical example of how ‘philosophy’ sends out new shoots is to be found in the case of Georg Cantor, a nineteenth-century German mathematician. His research on the subject of infinity was at first written off by his scientific colleagues as mere ‘philosophy’ because it seemed so bizarre, abstract and pointless. Now it is taught in schools under the name of set-theory.

There were three main new schools of thought: the Epicureans, the Stoics and the Sceptics. On the whole, if an Epicurean said one thing, a Stoic would say the opposite and a Sceptic would refuse to commit himself either way.