The revival of the philosophy of religion in the twentieth century: A (selective) history

I have noted in a previous post that natural theology, and in particular the classic arguments for the existence of God, declined within mainstream philosophy during the late nineteenth and early twentieth centuries. I also stated that the cause of this decline was the rise of a philosophy known as logical positivism/empiricism, advocated by an influential group of scholars known as the Vienna Circle. Logical positivists dismissed metaphysical statements – particularly statements about God – as ‘meaningless’, because they could not be verified empirically. Such severe restrictions on what could be considered ‘meaningful’ statements meant that, for over half a century, rational discussion of the existence of God ground to a halt within mainstream philosophy.

This opposition to theistic arguments was, actually, a continuation of a trend in mainstream philosophy that had begun with the publication of Immanuel Kant’s Critique of Pure Reason in 1781. Kant delivered what many considered to be a devastating critique of the classical theistic arguments, particularly the ontological and cosmological arguments. However, Kant himself did not advocate atheism or agnosticism. In his Critique of Practical Reason (1788), Kant devised a moral argument for God’s existence that did not rely on the ‘pure reason’ (i.e., classical and early-modern metaphysics) that he had rejected in his previous work.

For over a century after Kant, the Kantian moral argument (and variations upon it) continued to be defended in mainstream philosophy. So did a version of the design argument defended by Anglican Archdeacon William Paley in his influential work Natural Theology, or Evidence of the Existence and Attributes of the Deity, collected from the appearances of nature (1802). Although some regarded the design argument as dead due to the criticisms of the argument delivered by David Hume in his Dialogues Concerning Natural Religion (1779), Paley’s argument, written over twenty years after Hume Dialogues, actually took Hume arguments into account and avoided the logical pitfalls that Hume had criticised. (Actually, Hume had only critiqued a very specific version of the design argument defended by his character Cleanthes, a kind of Newtonian theist.) However, despite the popularity of Kantian moral arguments and Paleyan design arguments these, also, declined in popularity due to the rise of ‘naturalised ethics’ (e.g., utilitarianism) and Darwinian evolution. With the rise of logical positivism in the early twentieth century, this trend toward rejecting and/or ignoring theistic argument reached its zenith.

I have spoken mainly about trends in ‘mainstream’ philosophy. However, this does not mean that everyone followed this trend. In particular, toward the end of the nineteenth century, a revival of scholastic philosophy – today known as neo-scholasticism – involved the revival of certain classical theistic arguments that had not been widely discussed in centuries. ‘Scholasticism’ is the term used to collectively describe the philosophy and theology that dominated Catholic thought throughout most of the Medieval Period, reaching it's most impressive exposition in the philosophies of Thomas Aquinas, John Duns Scotus and Bonaventure during the High Middle Ages (12th and 13th centuries). Scholastic philosophy was subjected to a withering - though not particularly well-informed - critique in the early modernity, being explicitly rejected by philosophers as diverse as Rene Descartes, Thomas Hobbes, David Hume and John Locke. For the next few centuries, scholasticism was typically only mentioned in derisive comments or parodies. The revival of scholasticism in the late nineteenth century revolved initially around manuals written for Catholic colleges and seminaries that summarised and explained the philosophy of Thomas Aquinas (known as Thomism), as the most influential and greatest of the scholastic philosopher-theologians. The other scholastics mentioned above also received attention, but it was Aquinas’ thought that was the most influential, just as it had been during the late Middle Ages. The revival of scholastic philosophy also meant the revival of Aquinas’ Five Ways – a group of arguments for the existence of God summarised, most famously, in his Summa Theologiae, Part 1.

During the early-mid twentieth century – when logical positivism was at its most influential – a number of neo-scholastic philosophers began to revive and defend scholastic arguments for God’s existence. The most significant works during this period were the Reginald Garrigou-Lagrange’s God: His Existence and Nature (1934), Etienne Gilson’s God and Philosophy (1941), Eric Mascall's He Who Is: A Study of Traditional Theism (1943) and Existence and Analogy (1967), Jacques Maritain's Approaches to God (1954) and Celestine Bittle’s God and His Creatures (1953). Each of these books were significant contributions to the debate over God’s existence and how to talk rationally (philosophically) about God’s existence.

There were other works of note during this period by non-Catholics. The most note-worthy of these included Arthur James Balfour’s Theism and Humanism (1915), W.R. Sorely’s Moral Values and the Idea of God (1918), F.R. Tennent’s two-volume Philosophical Theology (1928, 1930), and A.E. Taylor’s Does God Exist? (1947). Of these, Taylor's work is, perhaps the most philosophically rigorous, while Tennent's discussion of the existence of God is, in my view, less impressive. Unfortunately, none of these works had as significant an impact on mainstream philosophy as they deserved. Balfour’s book advocated an argument not known as the ‘argument from reason’, while Sorely’s book presented a rigorous defense of the moral argument. Both these works influenced a young C.S. Lewis – who, in turn, has influenced many Christian philosophers and apologists of subsequent generations.

By the late nineteenth-century, scepticism of the validity of logical positivism had become sufficiently wide-spread to allow philosophers to “once again critically and cautiously investigate an area of philosophy which for half a century of more was deemed barren” (Reichenbach 1971, p. vii). The volume New Essays in Philosophical Theology, edited by atheist philosopher Antony Flew and Catholic philosopher Alasdair MacIntyre, was most influential in bringing “to the attention of the philosophical world questions which had long been passed off as meaningless” (Reichenbach 1971, p. vii). Although this volume was still strongly influenced by the scepticism about the meaningfulness of theological language that had been bred during the era of logical positivism, it was a big step in the direction of reviving philosophical theology. Among the essays publish in this volume was Antony Flew’s famous anti-theistic essay ‘Theology and Falsification’. Although this essay is commonly thought to have been strongly influenced by logical positivism, Flew in later years insisted that the purpose of the essay was actually to move beyond positivism’s narrow restrictions: “Instead of the arrogant announcement that everything that any believer might choose to say is to be ruled out of consideration a priori as allegedly constituting a violation of the supposedly sacrosanct verification principle…I preferred to offer a more restrained challenge” (cited in Flew & Varghese 2007, xvi). Flew’s essay presented a challenge to theists in the form of a story:

Let us begin with a parable. It is a parable developed from a tale told by John Wisdom in his haunting and revelatory article ‘Gods’.’ Once upon a time two explorers came upon a clearing in the jungle. In the clearing were growing many flowers and many weeds. One explorer says, ‘Some gardener must tend this plot’. The other disagrees, ‘There is no gardener’. So they pitch their tents and set a watch. No gardener is ever seen. ‘But perhaps he is an invisible gardener.’ So they set up a barbed-wire fence. They electrify it. They patrol with bloodhounds…But no shrieks ever suggest that some intruder has received a shock. No movements of the wire ever betray an invisible climber. The bloodhounds never give cry. Yet still the Believer is not convinced. ‘But there is a gardener, invisible, intangible, insensible to electric shocks, a gardener who has no scent and makes no sound, a gardener who comes secretly to look after the garden which he loves.’ At last the Sceptic despairs, ‘But what remains of our original assertion? Just how does what you call an invisible, intangible, eternally elusive gardener differ from an imaginary gardener or even from no gardener at all?’ (Flew 1955).

 Although Flew believed at the time that he had in his essay “achieved a total victory and there was no room for further debate” (Flew & Varghese, 2007, 25), Flew’s essay was instead taken as a challenge by theistic philosophers to show that theological language could be meaningful – that there was a rationally discernable distinction between, on the one hand, a Being that is invisible, intangible and elusive and, on the other, a being that is imaginary. The question was how to do so.

Interestingly, Flew's essay did reveal an obvious unfamiliarity with the history of philosophical theology. This challenge was, in fact, the primary focus of many leading Christian, Jewish and Muslim thinkers throughout late antiquity and the middle ages. Matthew Levering's recent book, Proofs of God: Classic Arguments from Tertullian the Barth outlines the approaches of several leading Christian thinkers during these periods quite well. Unfortunately, mainstream philosophy of religion was largely ignorant of much classical natural theology, so Flew's challenge had to be met again in the late twentieth century.

Initially, and rather curiously, the ontological argument received the most attention among philosophers, starting with Norman Malcolm’s description, in his contribution to New Essays, of a, as-yet un-discussed, second ontological argument within the writings of Anselm of Canterbury. Anselm had been the originator and most famous defender of the ontological argument – an argument that have been rejected by scholastic thinkers like Thomas Aquinas, but revived, in a modified version, by early-modern rationalists such as Descartes. Malcolm’s contribution to the discussion was soon eclipsed by that of Alvin Plantinga, who defended a modern version of the argument (now known as the 'modal ontological argument') in his book God and Other Minds (1967) and rapidly became the best-known defender of the ontological argument of the late twentieth century. However, the ontological argument has not received widespread support among theistic philosophers, primarily because of the highly abstract nature of the argument and the substantial criticisms of it by Aquinas and Kant. Instead, most theistic philosophers have attempted to meet Flew’s challenge in different ways.

If you find a garden hidden in the midst of a jungle, your first question will be: How did it get there? This is not only a rational question to ask, but one that demands an answer. To shrug your shoulders as say, ‘It’s just there, so what?’ would actually be an irrational response. This is the simple point that seems to have been ignored in Flew’s argument above. The Believer’s reasoning was highly logical: if a garden exists, you must infer the existence of a gardener, even if you cannot see, hear, smell, or touch this gardener. At the very least, the existence of a garden demands explanation. Similarly, theistic arguments (apart from the ontological argument) have always started with the existence of something – whether it be a complex biological structure like an eye (as in Paley’s design argument), the existence of teleological causation (as in Aquinas’ Fifth Way) or the existence of the universe itself (as in Samuel Clarke’s cosmological argument). You cannot see, smell or touch God, but you can infer God’s existence by the existence of the ‘garden’ God has made. Unsurprisingly, then, in order to meet Flew’s challenge, theistic philosophers began to revive (and revise) classic theistic arguments such as the cosmological and teleological arguments.

The first significant discussion of the cosmological argument was David Burell’s The Cosmological Argument (1967), but it was Bruce R. Reichenbach’s short (but influential) The Cosmological Argument: A Reassessment (1972) that really revived discussion of the argument. In just over a decade, numerous works – both favourable and critical – discussed various versions of the cosmological argument. The most notable works included Anthony Kenny’s The Five Ways: St. Thomas Aquinas’ Proofs of the Existence of God (1969), Dennis Bonnette’s Aquinas’ Proofs for God’s Existence (1972), William L. Rowe’s The Cosmological Argument (1975), William Lane Craig’s The Kalam Cosmological Argument (1979) and The Cosmological Argument from Plato to Leibniz (1980) and Mortimer J. Adler’s How to Think About God: A Guide for the 20^th-Century Pagan (1980).

Reichenbach revived a version of the contingency argument, Craig revived and significantly modernised the medieval Islamic kalam argument, and Bonnette and Adler discussed versions of Thomist-style cosmological arguments. These were impressive and formidable contributions to the debate over the existence of God.

Among them, Craig’s argument has become the most widely discussed in recent decades. Craig’s argument can be stated in a deceptively simple way.

1. Whatever begins to exist must have a cause of its existence.
2. The universe began to exist.
3. Therefore, the universe must have a cause of its existence.

The first premise is clearly based on the ancient metaphysical principle ex nihilo nil fit, ‘out of nothing, nothing comes’ – i.e. nothing can be caused by nothing. Craig (rightly) regards the second premise as the key premise in his argument, and he defends it along four lines of reasoning: two scientific arguments and two mathematical-philosophical arguments. The first two are based on the laws of thermodynamics and big bang theory. The second two are arguments against the possibility of an actually infinite series of causes/events, drawn from the philosophy of mathematics.

Theists pretty much dominated the discussion of the existence of God throughout the 1960s and 70s. However, theistic philosophers were not the only ones discussing the cosmological argument during this period. In his The Five Ways Anthony Kenny – a Catholic-turned-agnostic – presented what is probably still the most comprehensive critique of Aquinas’ famous arguments – a critique that provoked numerous responses by Catholic philosophers in the following decades. Similarly agnostic William L. Rowe’s The Cosmological Argument presented a formidable critique of the cosmological argument, focusing on Samuel Clarke’s argument from his famous work A Demonstration of the Being and Attributes of God (1705).

While theists were reviving some of the classic theistic arguments, another significant salvo against theism was delivered by Antony Flew in his God and Philosophy (1966) and The Presumption of Atheism (1976). In the former, developing his argument from “Theology and Falsification”, Flew argued that theism is not a coherent worldview because descriptions of God suffer from a “death by a thousand qualifications” (a phrase first used in “Theology and Falsification”). That is, Flew contended “that our starting point should be the question of the consistency, applicability, and legitimacy of the very concept of God”. Flew argued against classical theistic arguments, and went even further, questioning whether a coherent, positive idea of God is possible.

Moving on from this, in The Presumption of Atheism Flew co-opted the legal principle of the ‘presumption of innocence’ to argue that, just as in Anglo-derived legal systems, a defendant is innocent until proven guilty beyond reasonable doubt, so the most rational starting point in debating the existence of God should be ‘the presumption of atheism’ – that is, that the non-existence of God should be presumed, until the existence of God is proven beyond reasonable doubt. In other words, Flew argued that the burden of proof is on the theist to prove the existence of God. The atheist has to prove nothing. In reality, Flew’s argument was more an argument for agnosticism than for atheism; because, just as the presumption of innocence does not prove the innocence of the defendant, the ‘presumption of atheism’ does not prove the non-existence of God. So the book would have been better entitled The Presumption of Agnosticism.

Of course, the obvious response to Flew’s ‘presumption of atheism’ principle is to demonstrate the existence of God rationally – a project that theistic philosophers have continued over subsequent decades (see below). A second response was devised by William Alston, Alvin Plantinga and Nicholas Wolterstorff, which they called ‘Reformed Epistemology’. The volume Faith and Rationality (1983) and Plantinga’s God and Other Minds and Warrant and Proper Function (1993) are the most influential works defending this position. The contention of Reformed Epistemology is that religious belief, specifically belief in God, can be rational without appeal to evidence or argument. The Internet Encyclopedia of Philosophy summarises this argument:

The most explicit appeal to the reformed tradition is found in Alvin Plantinga’s work. Plantinga, when wondering how theistic belief might be grounded, suggests that we consider that Calvin may have been right when he said that God has created humans with an inner awareness of himself and it is this sensus divinitatis that is responsible for theistic belief.

Because of this sensus divinitatis, it is reasonable (Plantinga argues) for the theist – particularly the Christian theist – to presume the existence of God a priori. In other words, because human beings have a ‘God-sense’, that is, a natural inclination toward belief in some divine or transcendent purpose, it is perfectly reasonable for theists to start with the ‘presumption of theism’, rather than the ‘presumption of atheism’. This argument is based on the reality of what epistemologists call ‘properly basic beliefs’; beliefs that are reasonable to accept, provided there are no strong reasons to reject them, because they are fundamental to our understanding of reality. (For example, the belief that our senses give us reliable information about the world around us is a properly basic belief.)

Plantinga argues that, provided the atheist cannot show that theism is inherently incoherent or provide strong reason to doubt the existence of God, it is reasonable for the theist to take the existence of God as his/her starting point. Consequently, much of Plantinga’s other work, in his books God and Other Minds, God, Freedom and Evil (1974), The Nature of Necessity (1978), and Warranted Christian Belief (2000) has been to defend against the charges that the concept of ‘God’ is incoherent or that the problem of evil presents an irresolvable challenge to theism.

Another point that could be raised against Flew’s argument is that the ‘presumption of atheism’ logically implies the ‘presumption of naturalism/materialism’. Unlike the 'presumption of innocence', the 'presumption of atheism' necessarily implies the truth of some alternative to theism. In order to be truly rational, the atheist cannot simply deny the existence of God, but must also provide a rationally compelling alternative worldview. For the atheist, this is naturalism/materialism. The problem here is that many philosophers – not just theists – have, over the last century, become critical of naturalism as an adequate, or even coherent, worldview. Most notably, Plantinga’s ‘evolutionary argument against naturalism’, reasons that to attempt to explain the emergence of human intelligence as the by-product of mindless, purposeless natural processes undermines the basic presumption of all reasoning: that the human mind is capable of determining truth about reality. Considering that natural selection determines whether a particular mental trait will survive, not based on whether that trait helps the animal attain truth, but on the ‘fitness’ of the animal (i.e., its ability to reproduce in a particular environment), if we assume that the process of evolution is purposeless and directionless – as atheists must in order to be consistent naturalists – then the mind did not evolve to determine the truth about reality, but to survive. Hence, there is no way that we can know for sure – assuming both evolution and naturalism – that our thoughts about reality are actually true. In other words, Plantinga argues that naturalism effectively undermines the basis for rational thought. If, on the other hand, we accept – as we must, in order to be rational – the view that our minds are capable of getting at the truth (not that they are infallible, just possessing the potential for rational thought), then we must reject naturalism. If correct, this argument would not only undermine Flew’s argument, but completely undermine the epistemological basis for atheism/naturalism, as well.

Plantinga is not the only theistic philosopher to respond to Flew’s challenges. In response to Flew’s argument that theism is incoherent, Richard Swinburne wrote two key works in philosophical theology: The Coherence of Theism (1977, rev. ed. 1993) and The Existence of God (1979, 2nd. ed. 2004). In these two works, Swinburne attempts to present and defend a coherent understanding of theism that, in contrast to Plantinga, relies on objective philosophical arguments for the existence of God, rather than properly basic beliefs. Among the arguments that Swinburne defends are revised versions of the cosmological and teleological arguments.

One teleological (design) argument, in particular, has been strongly defended by Swinburne in his writings: the fine-tuning argument. In the 1960s, physicists began to discover that the existence of life in the universe is contingent upon several highly-improbable cases of ‘fine-tuning’ in the laws of physics. “Almost everything about the basic structure of the universe,” Robin Collins states, “for example, the fundamental laws and parameters of physics and the initial distribution of matter and energy – is balanced on a razor's edge for life to occur.” If the universe had been even a tiny bit different, then life could never have existed. This fact became the basis for a new design argument – one defended most prominently by Richard Swinburne, William Lane Craig, Robin Collins, Rodney Holder and Sir John Polkinghorne. Not only had the kalam cosmological argument been revised (in part) as the result of recent developments in cosmology, now a powerful new design argument had been devised based on recent developments in theoretical physics. Each of these developments helped to strengthen the case for theism and also provoked greater interest in theistic arguments within mainstream philosophy.

Up until the 1980s, only a handful of atheist philosophers wrote substantial critiques of philosophical theology. This is true of the period between 1955 and 1980, it is true of the early twentieth century, and it is also true of the preceding centuries. Serious philosophical discussion of the existence of God by atheists, agnostics and sceptics was actually unusual. This is because genuine atheism was rare prior to the twentieth century, but also because of the unpopularity of atheist writings. As I said, a handful of serious discussion of the existence of God can be found: Hume’s Dialogues, William Hammon’s Answer to Dr. Priestley’s Letters to a Philosophical Unbeliever (1782), Denis Diderot’s Promenade Du Skeptique (The Skeptic’s Walk) (1830), John Stuart Mill’s Three Essays on Religion (1874) and George John Romanes’ A Candid Examination of Theism (1878) count among the few. Most other atheist writings either presume the irrationality of theistic belief (e.g., the existentialist writings of Nietzsche, Satre and Camus), attempt to explain away religious belief as the product of natural processes (e.g., Ludwig Feuerbach and H.L. Mencken’s influential works), presuppose an atheistic and materialistic view of reality (e.g., the political writings of Marx and Engels) or else try to exclude theism from serious consideration a priori on dubious epistemological grounds (e.g., A.J. Ayer’s Language, Truth and Logic). Up until the revival of theistic philosophy in the later twentieth century there were few serious discussions of theism by atheist writers – despite that fact that today there is a common assumption among atheists that the existence of God was thoroughly refuted by the late nineteenth century.

However, around 1980 and in the decade following, serious atheist and agnostic thinkers – spurred on by the revival of theistic arguments in the previous decades – began writing in earnest. The most significant works among these include Anthony Kenny’s The God of the Philosophers (1979), Australian philosopher J.L. Mackie’s The Miracle of Theism (1982), Kai Nielsen’s God, Scepticism and Modernity (1989), Michael Martin’s Atheism: A Philosophical Justification (1990) and Richard M. Gale’s On the Nature and Existence of God (1991). Since the early 1990s dozens of serious atheist books have been added to this list. The most important among these are Jordan Howard Sobel’s Logic and Theism (2004), Graham Oppy’s Arguing About Gods (2006) and Michael Martin’s (ed.) The Cambridge Companion to Atheism (2007). (Unfortunately, quite a few less impressive works have received much greater attention, e.g. Richard Dawkins’ The God Delusion, Christopher Hitchens' god is Not Great and Hawking and Mlodinow's The Grand Design, just to name a few.)

The debate has continued, with little indication of slowing down. Theists have also added dozens of works to their (already lengthy) list of serious discussions of God’s existence. Among these are Barry Miller’s From Existence to God (1992), David Braine’s The Reality of Time and the Existence of God (1993), Stephen T. Davis’ God, Reason & Theistic Proofs (1997), John Polkinghorne’s Belief in God in an Age of Science (1998), Stephen R.L. Clark’s God, Religion and Reality (1998), Stephen M. Barr’s Modern Physics and Ancient Faith (2003), Alexander R. Pruss’ The Principle of Sufficient Reason: A Reassessment (2006), Brian Davies’ The Reality of God and the Problem of Evil (2006) and William Lane Craig and J.P. Moreland’s (eds.) The Blackwell Companion to Natural Theology (2009). That’s just the short list. 

Additionally, serious contributions to the discussion of classic theistic arguments have also been made. Studies of Thomas Aquinas' natural theology are among the most numerous, including: David Burrell's Aquinas: God and Action (1979, 3rd ed., 2016) and Knowing the Unknowable God: Ibn Sina, Maimonides, Aquinas (1986), Fredrick Copleston's Aquinas (1991), Christopher F.J. Martin's Thomas Aquinas: God and Explanations (1997), John Wippel's The Metaphysical Thought of Thomas Aquinas (2000), Norman Kretzmann's The Metaphysics of Theism: Aquinas' Natural Theology in Summa Contra Gentilies I (1997), Brian Davies' Thomas Aquinas: Contemporary Philosophical Perspectives (2002) and Aquinas: An Introduction (2006), Eleanor Stump's Aquinas (2003), Ralph McInerny's Praeambula Fidei: Thomism and the God of the Philosophers (2006), St. Thomas Aquinas (1982) and Aquinas and Analogy (1999), Rudi te Velde's Aquinas on God: The Divine Science of the Summa Theologiae (2006), Edward Feser's Aquinas: A Beginner's Guide (2009), Norman Kretzmann and Eleanor Stump's The Cambridge Companion to Aquinas (2010), Gaven Kerr's Aquinas' Way to God: The Proof in De Ente et Essentia (2015), etc.

Substantive discussions of ancient natural theology (Greek, Greco-Roman and early Christian) have also been made, most notably Lloyd Gerson's God and Greek Philosophy: Studies in the Early History of Natural Theology (1990) and Plotinus: Arguments of the Philosophers (1994), Matthew Levering's Proofs of God: Classic Arguments from Tertullian the Barth (2015) and A.N. Williams' The Divine Sense: The Intellect in Patristic Theology (2007).

This is just the tip of the iceberg. To list the number of substantive discussions of Christian, pagan, Jewish and Muslim thought would require a much longer list. I think it is safe to say that more books and articles have been written on God's existence since the mid-1950s than were written in the millennium prior to that. This does not mean that the debate is close to over – rather it means that the debate has begun again.

References:

Bolos, A. and K. Scott (n.a.), 'Reformed Epistemology' in Internet Encyclopedia of Philosophy.

Flew, A. 'Theology and Falsification', in A. Flew & A. MacIntyre (eds.), New Essays in Philosophical Theology (SCM Press, 1955).

Flew, A & R.A. Varghese, There Is a God: How the World's Most Notorious Atheist Changed His Mind (HarperOne, 2007).

Reichenbach, B.R., The Cosmological Argument: A Reassessment (Charles C. Thomas, 1972).