whose work influenced the Enlightenment included Francis Bacon and René Descartes. Some of the major figures of the Enlightenment included Cesare Beccaria, Denis Diderot, David Hume, Immanuel Kant, Gottfried Wilhelm Leibniz, John Locke, Montesquieu, Jean-Jacques Rousseau, Adam Smith, Hugo Grotius, Baruch Spinoza, and Voltaire. One particularly influential Enlightenment publication was the (Encyclopedia). Published between 1751 and 1772 in 35 volumes, it was compiled by Diderot, Jean le Rond d'Alembert, and a team of 150 other intellectuals. The Encyclopédie helped in spreading the ideas of the Enlightenment across Europe and beyond. Other landmark publications of the Enlightenment included Voltaire's Letters on the English (1733) and Dictionnaire philosophique (Philosophical Dictionary; 1764); Hume's A Treatise of Human Nature (1740); Montesquieu's The Spirit of the Laws (1748); Rousseau's Discourse on Inequality (1754) and The Social Contract (1762); Adam Smith's The Theory of Moral Sentiments (1759) and The Wealth of Nations (1776); and Kant's Critique of Pure Reason (1781). Topics Philosophy Bacon's empiricism and Descartes' rationalist philosophy laid the foundation for enlightenment thinking. Descartes' attempt to construct the sciences on a secure metaphysical foundation was not as successful as his method of doubt applied in philosophic areas leading to a dualistic doctrine of mind and matter. His skepticism was refined by Locke's Essay Concerning Human Understanding (1690) and Hume's writings in the 1740s. His dualism was challenged by Spinoza's uncompromising assertion of the unity of matter in his Tractatus (1670) and Ethics (1677). According to Jonathan Israel, these laid down two distinct lines of Enlightenment thought: first, the moderate variety, following Descartes, Locke, and Christian Wolff, which sought accommodation between reform and the traditional systems of power and faith, and, second, the Radical Enlightenment, inspired by the philosophy of Spinoza, advocating democracy, individual liberty, freedom of expression, and eradication of religious authority. The moderate variety tended to be deistic whereas the radical tendency separated the basis of morality entirely from theology. Both lines of thought were eventually opposed by a conservative Counter-Enlightenment which sought a return to faith. In the mid-18th century, Paris became the center of philosophic and scientific activity challenging traditional doctrines and dogmas. The philosophical movement was led by Voltaire and Rousseau, who argued for a society based upon reason as in ancient Greece rather than faith and Catholic doctrine, for a new civil order based on natural law, and for science based on experiments and observation. The political philosopher Montesquieu introduced