The Enlightenment movement flourished from around the early 1700s through the contribution of pioneering thinkers, referred to as the ‘philosophers’ or in the French form ‘philosophes’. They included such figures as the Frenchmen Voltaire, Montesquieu, d’Almenert, Turgot, Condorcet; Britons such as Locke, Hume and Gibbon; the Genevan Rousseau; the German-born, d’Holbach, Kant and Herder and the American, Franklin.[1] With such a diversity of thinkers and ideas, scholars have differed on the exact definition of the Enlightenment movement. This problem is predominately caused by the fact that it did not have a formal structure, creed or party organisation, nor an allegiance to some precise ‘-ology’ or ‘-ism’.[2] However, it is generally considered that the Enlightenment was a particular phenomenon in history with the view that human affairs should be guided by rationality rather than faith. [3] The philosophers during this segment of history championed human reason above all and regarded it as having the power to change society and unshackle man from the restraints of religious authority. This paved the way for a worldview, validated by science.[4]  This development was borne out of a new, social and intellectual background where most influential members of society, the cultural elite, had adopted reason as an essential part of their lives.  The cultural elites profoundly engaged with reason, unlike earlier centuries, where society was narrowly rationalized. The cultural horizon of most educated men in western Europe in the early seventeenth century was dominated by two almost unchallenged sources of authority: scripture and the classics.[5] During this period the cultural elite wrestled with the problem of how reason could fit in a world dominated by faith.   In eighteenth century thought however, there was a seismic shift; the question of the relationship between faith and reason dramatically altered. The question was no longer how reason could be reconciled with Christianity, but what place faith could have in a world grounded in reason and whether faith could thus have any legitimacy at all. This was the intellectual and cultural setting that gave way to the Enlightenment’s campaign against religion, and in particular against Christianity.[6]  The main motivating factors that contributed to the Enlightenment’s assault on Christianity will be discussed in the following paragraphs.

For Descartes and Malebranche, as for Spinoza and Leibniz, God was the ultimate paradigm of reality. The knowledge of God’s being formed the highest principle of knowledge from which all other certainties were inferred.   But this intellectual center of gravity changed during the eighteenth century. The diverse fields of knowledge-natural science, history, law, politics, art gradually departed from the authority and tutelage of traditional metaphysics and theology. They no longer looked at concepts of God for validation and legitimization; the various sciences themselves began to determine and define their own concepts within their specific remits. [7]

The advances in science brought humans closer to understanding the physical world in which they lived and each discovery was regarded as further progress in the advancement of learning. The seeds of enlightenment, though planted far earlier than the 17^th century, were deigned responsible for the pioneering of the sciences that challenged the core knowledge of existence, of life, of creation, and of the Creator. The Newtonian Philosophy, for example, exercised by Sir Isaac Newton and his followers, developed new knowledge on natural laws and mechanisms that creped through mainstream consciousness. Voltaire had stressed in his Lettres philosophiques (1733), that Newton’s achievement truly demonstrated that science was the key to human progress. The inability to reconcile the discoveries of the scientific method and the Bible’s claims to Man’s identity and the natural world, sparked an assault on Christianity. Broadly speaking, sixteenth-century thinkers still believed in the ‘homocentric’ (man centered) and ‘geocentric’ (earth centered) cosmos first advanced by classical Greek science. The new sciences of astronomy, cosmology and physics dislodged the old harmonies of an anthropocentric universe supported by Biblical accounts. Proof that the Earth was a tiny planet revolving around its sun, no more than a dot in a vast universe made up of an infinite number of galaxies, struck at Christianities’ claim of Man’s importance and specialness.[8] Through the 18^th century the Biblical accounts of Genesis, in particular concerning the age of the earth, were further contested with the discovery of countless fossils of extinct creatures. Towards the end of the 1660s, the Danish naturalist Steno, and Leibniz some years later, analyzed the existence of diverse geological strata across a very long period of time. [9] The marine fossils found in higher ground were found to be significantly older than the dating of the flood in the book of Genesis, suggesting they could not be attributed to this event. Furthermore, Maillet’s thesis of the Earth’s age was far older than what the Bible implies.[10] The naturist Meisler proposed, like Spinoza, a theory of evolution, although they lacked the scientific knowledge to support this view. Matter, for Meisler, was the primary source of all creative power in which the rational structure of the cosmos inheres, the equivalent of Spinoza’s natura naturans, that of which all other things are but ‘modifications’. Difficulties with the theory were noted at the time, matter and the framing of the laws of motion. But these were deemed minor compared with the absurd ‘contradictions’ and ‘impossibilities’ inherent in Creationism, Christian or Deist. [11]

From the later part of the seventeenth century, many of Europe’s greatest minds came to the conclusion that to truly grasp Man, they could not rely on incontestable faith in the Bible, nor dependence on the authority of the Greek and Roman thinkers.   All attempts to define Man’s nature, identity and history were challenged and re-examined.[12] The recurrent questions regarding the ‘self-determination of reason’ and the ‘autonomy of the moral’ begin life again within the age of the Enlightenment, but now the proper engine of investigation would be first hand experience, namely the scientific method, independently of the authority of the Bible and church. At the centre of this inquest was the dogma of original sin. The doctrine of original sin was central to Catholic and Protestant theology, where varying views regarding the nature of man existed; there were pessimists, optimists and rationalist views.  However, what was broadly accepted was a hierarchy, governed by God.   This was authoritatively grounded with reference to the passages of Genesis, where Man was viewed as a being lower than the angels, but higher than the beasts and that Man’s character had been tarnished by falling into sin due to his disobedience to God in the garden of Eden. [13]  The philosophes’ however, regarded the Christian view of Man to be irrational and this one of the bases of the attack against Christianity .  They opposed the characteristic of man as innately evil as traditionally imbibed from the story of ‘Original sin’.[14] As mentioned earlier, there existed extensive diversity of views within the Enlightenment, however, the concept of original sin is the common opponent upon which all the different trends of the philosophy of the Enlightenment joined forces and consequently the medieval dogma of original sin was dismantled.[15] Once the philosophes attacked this notion of original sin, studies into Human nature were given new life and the enlightenment made the study of Man into a science.[16] Thus, a new conception of the nature of man was born.  The Enlightenment thinkers claimed they had dismantled obsolete Christian claims about man and his place under God in nature and replaced it with true scientific knowledge, objectively grounded in facts, rather than myth. Although a vague concept allowing room for disputes, it nonetheless was argued that man was born innocent and that it was the environment in which he lived that made him evil. Rousseau described goodness as a probable outcome of the proper education of man, living in an ideal world, with the right set of circumstances, and in the absence of corrupt influences. [17] Diderot claimed it is“bad education, bad models, bad legislation that corrupt us”. [18] The denial of original sin and the claim of original innocence were a milestone and an indispensable part of the separation from Christian traditions.  This breakaway was idiosyncratic to the Enlightenment thinkers; to the extent that Kant received a hostile response when he merely asserted that Man had a ‘natural propensity’ for wickedness. For this, he was accused of relapsing into the old Christian ways and of being too close to the teachings of original sin. [19]

What was also idiosyncratic to the Enlightenments movement was the attack against Christianity’s exclusivist claims and the view that any given religion could be viewed as ‘the true faith’ or claim superiority over other religions.  This attack was borne out of the memories of sectarian strife that had plagued the seventeenth century. Since the sixteenth century until the Peace of Westphalia in 1648, rulers had invoked wars to impose their religious convictions on their opponents.[20] For the Enlightenment thinkers, the development of religious tolerance would avoid history repeating itself.   What was key in aiding this was the seismic epistemological shift that redefined truth and knowledge.   If we were to make a firm generalisation about the Enlightenment era it would be to characterise it as an era of Intellectualism, which unconditionally upholds the supremacy of thought, over and above religious doctrine. Reason or rationality embodied the central Enlightenment value.  By rationality, what was typically meant was objective thinking, without passion, prejudice or superstition and without reference to non-verifiable statements such as religious revelation.  Without exception, religion had to yield to the force of reason, not be held dependent on revelation and had to be accessible and not contrary to it.[21] This epistemological shift had an effect on the certainty of any form of knowledge. All knowledge now had to be regarded as tentative open to error. For example, through the pursuit of unfettered reason, the errors in science will be corrected by science alone and through this process truth will transpire.

This redefining of knowledge resulted in two central effects on Christianity. The first was the weakening of an exclusivist form of Christianity.   Religious authority of any sort became a matter of subjectivity and its objective source was repudiated and deemed dispensable.[22] Therefore, if religious claims no longer had the weight of certainly, if the dogma of Christianity no longer had any value, then the claims pertaining to exclusivity could no longer have the same weight. Given the dogmatic position of religious claims at the time, the Enlightenment thinkers became fervently opposed to Christian biblical notions of dogma and regarded them as narrow-mindedness.

The second effect was that those who were not atheists amongst the Enlightenment thinkers demanded that “true” religion be all-comprehensive, accessible to all men, to which a conceivable religion would be a ‘natural’ religion founded on reason, as opposed to Christianity itself founded on sacred texts.[23] Diderot, quite clearly expresses this attitude in his Philosophical Thoughts,

“Men have banished divinity from their midst; they have relegated it to a sanctuary; the walls of a temple are the limits of its view; beyond these walls it does not exist. Madmen that you are, destroy these enclosures which obstruct your horizon; liberate God see Him everywhere where He actually is else say that He does not exist at all." [24]

The nature of God was also criticized in the same vain. There was much controversy about the moral nature of God.  The Enlightenment thinkers argued that the Christian God contravened mental categories of equality, freedom and moral respect for basic human rights.  They took issue with the Christian view that so few would share the grace of this God and so many would be eternally dammed. They also contested that this was a God of forgiveness, given that he is deemed to refuse to forgive the sins of so many people. Such a God was deemed tyrannical and fictional.[25]  

The Enlightenment thinkers further concluded that when subjected to the criteria of reason and history, Biblical Christianity failed. This failing then brought about severe doubt on the biblical accounts, which included claims to miracles. This doubt grew ever more with philosophical developments. Spinoza for example argued that “God” was the same as nature. (A comparable sort of atheism, or naturalistic pantheism, was later articulated by Barn d’Holbach). [26] This radical view of God’s nature implied that any sort of miracle, in so far as acting against the laws of nature would be regarded as absurd. This represented a full frontal attack on the very conception of a Christian God. According to Spinoza, the laws of nature were a product of God’s will, which flowed from the necessity and perfection of the divine nature. This meant that a miracle would in fact be God acting against his own nature. Thus, according to Spinoza, a literal belief in miracles would ironically, be to deny God since it would be a contradiction of the nature of God.[27] Furthermore, Hume argued that the idea that a reasonable man could believe in a miracle was a contradiction in terms. According to Hume, there could never be enough evidence in favour of a miracle since there would always be proportionally more evidence in favour of natural laws functioning as they were meant to function. [28] Not to mention the notion of God interfering with the universe undermined the established machine like Newtonian view of the world, governed by inexorable laws. Newton and his followers asserted the permanent miracle of gravitation and the general laws of the universe, accounting for God merely as a universal ruler who was confined to working through natural causes. Such claims to miracles were deemed violations of those laws, implying a contradiction since the laws of nature were considered immutable.[29] Nevertheless, even if this were deemed possible, it was considered absurd to think such a God would in fact interfere in human affairs. Voltaire wrote:

“the most absurd of all extravagances to imagine that the infinite Supreme Being would on behalf of three or four hundred emmets on this little atom of mud 'derange the operation of the vast machinery that moves the universe?” [30]

Given these contentions, miracles could not be rationally maintained. Hence, the Enlightenment thinker’s claimed that the Christian, anthropomorphic ‘God of miracles was irreconcilable with reason and should be abounded. More importantly, Christianities exclusivist claims again were weakened, since miracles were its means of proving Christianity and a fundamental element in establishing its dogma.

It is important however, to insist upon the scope and complexity of Enlightenment attitudes towards faith. They were not all motivated by unbelief or a desire to eradicate Christianity. Only a minority of intellectuals wanted to replace religion with complete non-belief. For one thing, most believed that science and philosophy, though causing doubt upon the existence of the specifically Christian God, nevertheless pointed to some sort of presiding deity, a deity that was a rational alternative namely deism. A God which, beyond its mere fact of existence, nothing more could be known of.[31] Such a God was indifferent to the moral choices of men. [32] This distant and impersonal form of God became solidified by the turn of 18th century where the notion of divine intervention was excluded from major areas of life, amongst the bourgeoisie. In contrast with earlier societies, interpenetration of faith was a major factor in everyone’s life, whether in the form of God’s approval or wrath, and reward or punishment, which constituted the psychological framework of traditional belief.[33] Consequently, this interfering view of God and providential help from above was deemed backward and talk of the uneducated and ‘ignorant masses’, and regarded an attitude of the common people, namely peasants and labours.[34] This solidified the attack on Christianity by grounding reason in an elite attitude and associating traditional Christian doctrine with an uneducated perspective.

The motivating factors behind the assault on Christianity were the need for religious tolerance, the pressure for Christianity to become aligned with reason, which had become the dominant paradigm of the era and the need for faith to be reconciled with the newly established form of knowledge known as science. These pressures resulted in long term consequences on the very nature of Christianity in Europe.

Amongst these was the emergence of anti-Christian intellectual structures which concurrently entailed an internal structural alternation of Christian belief within its traditional forms. The external attacks on Christianity had made the faith obsolete and absurd, contravening emerging intellect and moral categories. Internal attempts to establish a form of Christianity that was in line with reason, resulted in undermining the authority of the Bible and the abandonment of essential doctrines of the Christian faith. The shift in the understanding of religious values had very important consequences on the conception of God. From being seen as a personal power moving outside and beyond the created world interacting with human affairs, God became indifferent and restricted to working through natural causes and ‘obeyed natural laws’ accessible to human study.

The Enlightenment has shaped the conception of God and faith in Europe and much of the Western world, where enduring debates on the relationship between God and science, faith and rationality and religion and morality, hark back to the earliest contentions of the ‘philosophes’. The very nature of the modern Church has been forged by these debates and reflect the challenge posed to traditional Christian doctrine by the Enlightenment thinkers.