Baruch de Spinoza and later Benedict de Spinoza was a Dutch Jewish philosopher. Revealing considerable scientific aptitude, the breadth and importance of Spinoza's work was not fully realized until years after his death. By laying the groundwork for the 18th century Enlightenment and modern biblical criticism, he came to be considered one of the great rationalists of 17th-century philosophy. His magnum opus, the posthumous Ethics, in which he opposed Descartes's mind?body dualism, has earned him recognition as one of Western philosophy's most important contributors. Philosopher Georg Wilhelm Friedrich Hegel said of all contemporary philosophers, 'You are either a Spinozist or not a philosopher at all.'