While skepticism and doubt have had a presence in human thought for nearly as long as religious faith has existed, they have had a place within religious thought rather than in opposition to it for the vast majority of their existence. Doubt was generally employed by religious thinkers for the purpose of strengthening and explaining their faith, as can be seen in the numerous “proofs” for the existence of God formulated by the great theologians of the Middle Ages, such as Thomas Aquinas and Anselm of Canterbury. With the new science and philosophy of the Enlightenment, however, unbelief began to be seen as a viable alternative option that stood in opposition to faith. In addition to the popular deism of the Enlightenment, espoused by such important figures as Voltaire and Maximilien Robespierre, atheism also found its first explicit adherents among such figures of the French Enlightenment as Baron d’Holbach and Jacques André Naigeon. This new view of disbelief would have a major influence on subsequent generations of thinkers in the West as proponents of religion now had to contend with disbelief as a rival system of thought and many of the most influential philosophies, such as those of Friedrich Nietzsche, Karl Marx, and Jean Paul Sartre, supported and often assumed atheism. Among the numerous new concepts introduced by the philosophers of the Enlightenment, one of those which has had the longest lifespan and the greatest impact has been the introduction of disbelief as a viable alternative position to religious faith.
Reasonable Doubt in the Middle Ages
One of the most central philosophical pursuits of the Middle Ages was the attempt to reconcile faith and reason.1 Medieval thinkers had inherited both the religious tradition of the ancient Middle East, which they saw as representative of faith, and the philosophical tradition of ancient Greece, which they saw as representative of reason. In their attempts to synthesize the two, the primary question they encountered was whether the existence of God, the primary object of faith, could be proved through the use of reason alone. “Some of the greatest thinkers who have ever lived have pored at length over this question.”2
One of the most remarkable features of Medieval philosophy is the centrality of this question when compared with the apparent nonexistence of any separate class of nonbelievers. Not only are there no surviving writings by or about any person espousing outright unbelief during the Middle Ages, but according to Sarah Stroumsa, “in the discussions of God’s existence the actual opponents” of the philosophers examining the question “are not identified as individuals. As a group they are sometimes referred to as heretics, unbelievers, materialists, or skeptics.”3
Some of the greatest minds of the Middle Ages, then, dedicated large portions of their work to arguing against an entirely theoretical unbelief. When Anselm of Canterbury formulated his ontological argument4 and Thomas Aquinas formulated his famous “five ways” to prove the existence of God,5 they themselves assumed doubt in their writings in order to strengthen faith through reason and to demonstrate that faith and reason are compatible and complimentary.
Later, in the fifteenth century, however, William of Occam set about undoing the synthesis which had been accomplished by Anselm, Aquinas, and others like them. Occam believed that “logic and theory of knowledge had become dependent on metaphysics and theology” as a result of their work and that they had made reason subservient to faith.6 He “set to work to separate them again.”7 As a result of his work to separate faith and reason, according to Richard Tarnas,
there arose the psychological necessity of a double-truth universe. Reason and faith came to be seen as pertaining to different realms, with Christian philosophers and scientists, and the larger educated Christian public, perceiving no genuine integration between the scientific reality and the religious reality.8
Deism and Its Clockwork Universe
As scientific knowledge in Europe continued to increase exponentially, the gap between faith and reason continued to widen. Faith had grown detached from reason in ever more literal interpretations of the Bible and the sola fide, or “faith alone,” dogma of Protestantism, whereas reason increasingly freed itself from reference to faith and instead found its abode in the empirical sciences and “natural theology,” an approach to religion based on reason and experience rather than speculation and appeal to revelation, of Enlightenment thinkers like Descartes.9
Traditional Christianity, with its miracles and saints, came increasingly to be viewed as outdated and superstitious.10 This was especially true in the light of Newtonian physics. A mechanistic universe which operated consistently according to a standard set of laws did not allow for “alleged miracles and faith healings, self-proclaimed religious revelations and spiritual ecstasies, prophecies, symbolic interpretations of natural phenomena, encounters with God or the devil” and so on and so these ideas increasingly came to be viewed “as the effects of madness, charlatanry, or both.”11 According to Jacques Barzun, “religion as such [was] not attacked; it [was] redefined into simplicity.”12 In the light of this new scientific knowledge and the new views of religion it engendered, a new religious movement was needed.
The new religious movement that emerged from this situation was deism. Deism allowed that “one may well be overawed by the Great Archetict and His handiwork;”13 after all, “Newton’s cosmic architecture demanded a cosmic architect.”14 However, “the attributes of such a God could be properly derived only from the empirical examination of his creation, not from the extravagant pronouncements of revelation.”15 The deists also prescribed that religion include much emphasis on “good morals,” as they, like the belief in a creator, “are universal” as well.16
This rather tenuous set of beliefs, however, could not hold for long. Samuel Clarke, an early English Enlightenment philosopher, noted in a letter to Gottfried Wilhelm Leibniz that
The notion of the world’s being a great machine, going on without the interposition of God as a clock continues to go without the assistance of a clockmaker, is the notion of materialism and fate and tends (under pretense of making God a supramundane intelligence) to exclude providence and God’s government in reality out of the world. And by the same reason that a philosopher can represent all things going on from the beginning of the creation without any government or interposition of providence, a skeptic will easily argue still further backward and suppose that things have from eternity gone on (as they now do) without any true creation or original author at all but only what such arguers call all-wise and eternal nature.17
As more thinkers began to realize this, “the rationalist God … soon began to lose philosophical support.”18
The Advent of Athéisme
While “most of these empiricists of the first generation acknowledged God as the Creator, the Great Watchmaker, who set the cosmos in motion and then let it run on its own,” writes Barzun,
the thought then occurred that sensations imply the existence of matter; therefore ideas, feelings, knowledge – life itself – are but the interplay of bits of stuff. Matter in motion acts as cause, and the effect is another part of matter in some other motion. God has no point of entry into the relation; very likely He does not exist. There is in truth no need for Him.19
From this line of reasoning arose the first adherents to athéisme, the denial of the existence of any God at all.
The first known person to claim this position for himself was Paul-Henri Thiry, Baron d’Holbach. In his book The System of Nature or, the Laws of the Moral and Physical World, originally published in 1770, d’Holbach became the first Western thinker to explicitly deny the existence of God and apply the term “atheism” to his belief system.20 In the same book, he expounded a view of the universe which was very similar to that of the deists. He posited an universe which functioned entirely according to mechanical laws and free of any divine or otherwise spiritual outside intervention, holding to such a strict materialistic determinism as to rule out free will entirely. In it, d’Holbach, like the deists, also argues that religious beliefs like miracles are superstitions from a more ignorant age and the product of misunderstanding and fear. He goes a step farther than the deists, however, and includes the idea of God in his list of religious concepts in this category.
Denis Diderot, who edited and annotated d’Holbach’s volume, also came to espouse similar beliefs. Throughout his lifetime, he made “the gradual transformation … from religious belief to Deism, then to skepticism, and finally to a materialism ambiguously joined with a deistic ethics.”21 In his life and even on this latter point, ethics, Diderot passed “from critical effort based on Reason to a conception of man and society in which impulse and instinct are seen as stronger than Reason.”22
The physician and philosopher Julien Offray de La Mettrie was willing to go a step further, drawing out the logical conclusions of atheism and a determinist and materialist worldview, in his book Man a Machine, first published in 1748.23 As the title implies, La Mettrie asserted that, as man is a part of the universe and its mechanical laws, man must himself be mechanical, “an organic machine whose illusion of possessing an independent soul or mind was produced simply by the interplay of its physical components.”24 A human being was, in short, nothing more than “a chemical, glandular, and electrical machine.”25 As Richard Tarnas points out, the ethical implications of this were obvious: “hedonism was the ethical consequence of such a philosophy, which La Mettrie did not fail to advocate.”26 Atheism had grown from deism, which, in turn, had grown out of Medieval Christianity; with his rejection of Christian ethics, La Mettrie had severed the last tie between the unbelief of Enlightenment thinkers and their roots in the Western Christian tradition.
The Death of God
Disbelief was no longer just the doubt and needs for “proofs” that had been present in Medieval thought. It was no longer theoretical and it was no longer subservient to the needs of religious thinkers in their attempts to strengthen the case for faith. Disbelief had become a new and distinct religious category in its own right. Later generations of Western thinkers, drawing on the thought of the Enlightenment in religious matters just as they did in political and economic matters, carried on the Enlightenment’s new movement of disbelief. According to Richard Tarnas,
It would be the nineteenth century that would bring the Enlightenment’s secular progression to its logical conclusion as Comte, Mill, Feuerbach, Marx, Haeckel, Spencer, Huxley, and, in a somewhat different spirit, Nietzsche all sounded the death knell of traditional religion. The Judaeo-Christian God was man’s own creation, and the need for that creation had necessarily dwindled with man’s modern maturation.27
Most Western philosophy after the Enlightenment, in fact, no longer felt the need to even argue for or against the existence of God. Rather, philosophers like those named by Tarnas as well as many others simply assumed the nonexistence of God as a fact and formulated their philosophy without regard to the existence of a deity. Ludwig Feuerbach, one of these nineteenth century philosophers who built on the work of the Enlightenment philosophers, stated explicitly that
The question as to the existence or non-existence of God, the opposition between theism and atheism, belongs to the sixteenth and seventeenth centuries but not to the nineteenth. I deny God. But that mans for me that I deny the negation of man. In place of the illusory, fantastic, heavenly position of man which in actual life necessarily leads to the degradation of man, I substitute the tangible, actual and consequently also the political and social position of mankind. The question concerning the existence or non-existence of God is not important but the question concerning the existence or non-existence of man is.28
For the philosophers of the Middle Ages, Renaissance, and even the Enlightenment, “the question concerning the existence or non-existence of God” had, of course, been seen as being of the utmost importance. Only a philosopher who lived in the wake of the Enlightenment and accepted its presuppositions in materialism and determinism would have been able to make such a statement as Feuerbach’s; his words are demonstrative of how influential the atheism of the Enlightenment had become. Though his words about himself can only fairly be applied specifically to Feuerbach and do play an important role in his unique philosophy, much the same sentiments can with confidence be assigned to the vast majority of other great philosophers who followed the Enlightenment.
The disbelief of the Enlightenment has also had a major effect on popular philosophy and religion, especially in Europe. According to the 2005 Eurobarometer Poll, approximately 18% of the citizens of countries in the European Union report that they “don’t believe there is any kind of spirit, God or life force.”29 This is a significant change, of course, from the situation in Europe during the Middle Ages, when Anselm, Aquinas, and others like them directed their arguments for the existence of God against vague, theoretical, and unnamed “skeptics” and “heretics.”
The new prominence and popularity of disbelief also had a major effect within Christianity for much the same reason. Unbelievers were now real and unbelief itself now a viable alternative to religious faith; as a result, many believers felt a need to go on the defensive. Doubt, and even any application of reason to Christianity and to issues of faith, came to be viewed as insidious enemies, not as the means to the strengthening and further understanding of faith as in previous generations.30 In removing a rational element from faith, faith came to be ever more irrational and, occasionally in later Western history, even anti-rational, as is evidenced by the growth and influence of Christian and semi-Christian sects focused on otherworldly mysticism, ecstatic experience, and emotionalism to the exclusion of logical thought and scientific knowledge in America and Europe during and following the Enlightenment. Christian apologetic also took on a more forceful character, as Christian apologists found it necessary to concede as little as possible to the unbelievers, such as defending extremely literal interpretations of the six-day creation and worldwide flood described in the biblical book of Genesis, whereas earlier generations of Christians had generally interpreted these events in allegorical and mystical terms.31 Christian apologists also found it necessary to attack their unbelieving opponents with a new zeal, labeling them as “missionaries of evil” and focusing the bulk of their apologetic efforts on disbelief rather than on other religions or Christian heresies.32 The attempts to reconcile faith and reason and the use of doubt as a faith-building tool had become things of the past.
Doubt has been implicit within and an aspect of religious belief for as long as religious ideas have existed. This is especially true of the Christian religious tradition, whose most intellectual adherents found reasonable arguments for the existence of God to be necessary in the course of their attempts to reconcile the inheritances they had received from both ancient Judaism and ancient Athens. The eventual reconciliation of faith with reason, though accomplished during the Middle Ages, fell apart as the Middle Ages ended, largely under the influence of William of Occam. With the dawn of the Enlightenment in Europe and especially the new scientific knowledge which it brought with it, the separation that had been wrought between faith and reason widened continually and ever more deeply. Deism originally rose from the “reason” side of this split as a supposedly reasonable alternative to religious superstition; it attempted to formulate a set of religious beliefs that was pared down to the basics of the existence of a creator God and a moral system he had ordained alongside the laws of the universe. As the universe and human beings themselves came to be viewed increasingly as natural machines, however, there was less and less need for the existence of a God or the plausibility of holding to a moral system based on one. With d’Holbach, athéisme found its first outspoken spokesman, extolling a worldview in which there was no God and everything that existed was part of the material world. As with much Enlightenment philosophy, this view subsequently gained such popularity and influence among philosophers that it became the assumed standpoint of later generations of philosophers. As with any great new idea, the effects became tremendous once atheism reached the ears of the people at large, reshaping the nature of both religious belief and disbelief throughout the nineteenth and twentieth centuries and continuing through to today.
1 Hans Küng, Great Christian Thinkers (New York: Continuum, 1994), 108-9.
2 William Raeper and Linda Smith, A Brief Guide to Ideas (Oxford: Lion Publishing, 1997), 55.
3 Sarah Stroumsa, Freethinkers of Medieval Islam: Ibn al-Rawandi, Abu Bakr al-Razi and their Impact on Islamic Thought (Leiden: Brill, 1999), 122-3.
4 Raeper, A Brief Guide, 59.
5 Nils Ch. Rauhut, ed., Readings on the Ultimate Questions: An Introduction to Philosophy, Second Edition (New York: Penguin Academics, 2007), 380-3.
6 Bertrand Russell, The History of Western Philosophy (New York: Simon & Schuster, 1972), 472.
8 Richard Tarnas, The Passion of the Western Mind: Understanding the Ideas that Have Shaped Our World View (New York: Ballantine Books, 1993), 302.
10 Jaroslav Pelikan, The Christian Tradition, A History of the Development of Doctrine, Vol. 5: Christian Doctrine and Modern Culture (since 1700) (Chicago: The University of Chicago Press, 1989), 66.
11 Tarnas, The Passion, 303.
12 Jacques Barzun, From Dawn to Decadence: 1500 to the Present, 500 years of Western Cultural Life (New York: HarperCollins Publishers, 2000), 361.
14 Tarnas, The Passion, 308.
16 Barzun, From Dawn, 361.
17 Samuel Clarke, Gottfried Wilhelm Leibniz: Philosophical Papers and Letters: A Selection, ed. Leroy E. Loemaker (Norwell: Kluwer Academic Publishers, 1989), 677.
18 Tarnas, The Passion, 308.
19 Barzun, From Dawn, 365.
20 Paul Henri Thiry, Baron d’Holbach, The System of Nature or, the Laws of the Moral and Physical World, tr. H.D. Robinson (New York: G.W. and A.J. Matsell, 1835).
21 Tarnas, The Passion, 310.
22 Barzun, From Dawn, 373.
23 Julien Offray de La Mettrie, Machine Man and Other Writings, ed. Ann Thomson (New York: Cambridge University Press, 1996).
24 Tarnas, The Passion, 310.
25 Barzun, From Dawn, 367.
26 Tarnas, The Passion, 310.
28 Ludwig Feuerbach, quoted in Raeper, Brief Guide, 122.
29 European Commission, Directorate General Press and Communication, Eurobarometer: Social values, Science, and Technology (June 2005) http://ec.europa.eu/public_opinion/archives/ebs/ebs_225_report_en.pdf (accessed 19 November 2011).
30 James C. Turner, Without God, Without Creed: The Origins of Unbelief in America (Baltimore: Johns Hopkins University Press, 1986), 144.
31 Turner, Without God, 143-4.
32 Pelikan, The Christian Tradition, 181.
Barzun, Jacques. From Dawn to Decadence: 1500 to the Present, 500 years of Western Cultural Life. New York: HarperCollins Publishers, 2000.
d’Holbach, Paul Henri Thiry, Baron. The System of Nature or, the Laws of the Moral and Physical World. Translator H.D. Robinson. New York: G.W. and A.J. Matsell, 1835.
European Commission, Directorate General Press and Communication. Eurobarometer: Social values, Science, and Technology. June 2005. http://ec.europa.eu/public_opinion/archives/ebs/ebs_225_report_en.pdf (accessed 19 November 2011).
Küng, Hans. Great Christian Thinkers. New York: Continuum, 1994.
La Mettrie, Julien Offray de. Machine Man and Other Writings. Editor Ann Thomson. New York: Cambridge University Press, 1996.
Loemaker, Leroy E., editor. Gottfried Wilhelm Leibniz: Philosophical Papers and Letters: A Selection. Norwell: Kluwer Academic Publishers, 1989.
Pelikan, Jaroslav. The Christian Tradition, A History of the Development of Doctrine, Volume 5: Christian Doctrine and Modern Culture (since 1700). Chicago: The University of Chicago Press, 1989.
Raeper, William and Linda Smith. A Brief Guide to Ideas. Oxford: Lion Publishing, 1997.
Rauhut, Nils Ch., editor. Readings on the Ultimate Questions: An Introduction to Philosophy, Second Edition. New York: Penguin Academics, 2007.
Russell, Bertrand. The History of Western Philosophy. New York: Simon & Schuster, 1972.
Stroumsa, Sarah. Freethinkers of Medieval Islam: Ibn al-Rawandi, Abu Bakr al-Razi and their Impact on Islamic Thought. Leiden: Brill, 1999.
Tarnas, Richard. The Passion of the Western Mind: Understanding the Ideas that Have Shaped Our World View. New York: Ballantine Books, 1993.
Turner, James C. Without God, Without Creed: The Origins of Unbelief in America. Baltimore: Johns Hopkins University Press, 1986.