Ethics

The Dutch Jewish philosopher Baruch or Benedict de Spinoza was a very influential iconoclast. In fact, Hegel said of all modern philosophers, You are either a Spinozaist or not a philosopher at all. If you're familiar with the history of philosophy, you know that Spinoza's magnum opus, the posthumous Ethics, in which he opposed Descartes's mind-body dualism, was placed on the Church's Index Librorum Prohibitorum (List of Prohibited Books).