Baruch Spinoza. Engraving of Baruch Spinoza (1632- 77), Dutch philosopher. Spinoza supported himself by doing lens-grinding work whilst writing his philosophical works. Spinoza believed that God and the universe were identical entities; to under- stand the universe was to understand the mind of God. Spinoza corresponded with Oldenburg (secret- ary of the English Royal Society), Huygens, Boyle and Leibniz. In his Ethica (1677), Spinoza used a commentary on Euclidean geometry to derive meta- physical system. Spinoza died of a respiratory disease aggravated by glass dust in his lungs. Although ignored during his life, Spinoza is now seen as one of the most important philosophers.