Philosophy and Religion in Western Thought

If many of the central figures of the European Enlightenment were trenchant critics of established religion, they often enough professed views about a divine origin or general governance of the created order. This is true of Denis Diderot (1713–1784), Voltaire (1694–1778), and Jean-Jacques Rousseau (1712–1778). The most important works of this time regarding religion are David Hume's (1711–1776) Natural History of Religion (1757) and Dialogues concerning Natural Religion (1779, but first written in the 1750s). The former deals with the causes of religion, as it originates in human nature and society, while the latter examines the reasons or putative grounds for believing in a God or gods. The force of Hume's work resided in his claim that the culminative arguments of natural religion do not establish the existence of any deity that could be the proper object of religious belief. If revelation cannot be authenticated by reason, it might seem that the only answer that can be given to the question "Why does anyone believe in God or gods?" is that such practices have a natural origin. An investigation of these causes is the subject of the Natural History of Religion. Central to Hume's argument there is the provocative contention that the source of a belief in deities is to be found in numerous human pathologies that derive from a fear of the unknown.

It was not only Hume who fired a successful broadside at the theistic tradition of Western philosophy. Immanuel Kant (1724–1804) sought to refute the questionable metaphysical assumptions he believed inherent in the traditional "speculative proofs" for the existence of God, by demonstrating the incoherence of the ontological argument, the cosmological proof, and the argument from design. The effect of Kant's onslaught was to undermine not only the substance of these arguments but also trust in their philosophical efficacy. After him, philosophers such as Georg Wilhelm Friedrich Hegel (1770–1831) chose to construct a metaphysico-religious view of "Absolute Spirit," a highly suggestive concept that draws on pantheistic ideas of the identity of the universe and God, together with theistic ideas concerning the necessary "self-consciousness" of God. The peculiarity of Hegel's view lies in his notion that the mind of God becomes actual only via the minds of his creatures.

While Kant and Hegel by no means excluded religious topics or even religious sentiments from their work, many of their subsequent readers appropriated only the negative conclusion that could be distilled from their critique of traditional theism. Thus it is unsurprising that they were followed either by fideistic thinkers such as Søren Kierkegaard (1813–1855) or else resolutely antitheistic thinkers, of whom Ludwig Feuerbach (1804–1872), Arthur Schopenhauer (1788–1860), Karl Marx (1818–1883), Friedrich Nietzsche (1844–1900), and Sigmund Freud (1856–1939) were the most influential. This atheistic legacy was prosecuted still further in the twentieth century by luminaries of the Continental tradition such as Martin Heidegger (1889–1976) and Jean-Paul Sartre (1905–1980), whose philosophical systems leave no room for God.