“Idealism” is a term that had been used sporadically by Leibniz and his followers to refer to a type of philosophy that was opposed to materialism. Thus, for example, Leibniz had contrasted Plato as an idealist with Epicurus as a materialist. The opposition to materialism here, together with the fact that in the English-speaking world the Irish philosopher and clergyman George Berkeley (1685–1753) is often taken as a prototypical idealist, has given rise to the assumption that idealism is necessarily an immaterialist doctrine. This assumption, however, is mistaken. With the possible exception of Leibniz, the idealism of the Germans was not committed to the type of doctrine found in Berkeley according to which immaterial minds, both infinite (God’s) and finite (those of humans), were the ultimately real entities, with apparently material things to be understood as reducible to states of such minds—that is, to ideas in the sense meant by the British empiricists.