A Natural History of Natural Theology: The Cognitive Science of Theology and Philosophy of Religion

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Natural Theology and Natural History

Natural theology and the cognitive science of religion are two fields that seem to have little in common. Natural theology is concerned with obtaining knowledge of God through experience and reasoning, whereas the cognitive science of religion studies religious beliefs and practices through naturalistic, scientific methods. This chapter shows how key questions in both disciplines are nevertheless interrelated and how results from the one can have implications for the other. Throughout its history, natural theology has always maintained a dialogue with the sciences, which makes cognitive science of religion potentially interesting to natural theologians.

Two Questions about Religion

As every enquiry, which regards religion, is of the utmost importance, there are two questions in particular, which challenge our principal attention, to wit, that concerning its foundation in reason, and that concerning its origin in human nature.

—David Hume (1757, 1)

In The Natural History of Religion, David Hume (1757) posed two central questions about religion: is religious belief reasonable, and what is it about human nature that makes people hold such beliefs? The first question is the subject matter of natural theology, as it examines on what grounds one can rationally hold particular religious beliefs. The second question concerns the causal origin of religious beliefs. In the eighteenth century, natural history was the intellectual endeavor of uniting empirical facts through theoretical, explanatory frameworks. Traditionally, the natural history of religion and natural theology have been treated as separate questions. Hume’s Natural History of Religion traces the historical development of religion and its roots in human psychology (the second question), whereas his posthumously published Dialogues Concerning Natural Religion (1779) considers the cogency of natural theological arguments (the first question).

As Hume already adumbrated, and as we will argue in this book, the two questions on religion are intimately connected. One of our main claims is that an understanding of the foundation of religion in reason requires a better insight into how reason and causal origin relate, in particular where intuitions in natural theology originate. Hume proposed that such intuitions come to mind simply because they are plain to us: The whole frame of nature bespeaks an intelligent author; and no rational enquirer can, after serious reflexion, suspend his belief a moment with regard to the primary principles of genuine Theism and Religion (Hume 1757, 1). Nevertheless, he expressed skepticism about the design argument in Dialogues, suggesting that intuitions that underlie natural theology are not self-evident after all. If these intuitions are not self-evident, we can ask whether the inference to theism through reason and observation is warranted.

The natural history of religion and natural theology also intersect in the extent to which causal explanations of religion, offered by the sciences, have implications for the reasonableness of religious beliefs. Simply put, does a naturalistic (evolutionary, cognitive) explanation for religious beliefs debunk these beliefs? The term debunking is commonly used in a strong sense, namely to refute, to prove that something is false. However, philosophers usually employ the term in a more restricted way, in the sense of to explain away. Debunking arguments examine the causal history of a particular belief in a way that undermines that belief. For instance, suppose one can explain religious belief as an adaptation that allows us to increase cooperative behavior: through religious beliefs and the accompanying costly religious commitments such as dress codes and food restrictions, humans can reliably signal that they are part of the in-group, which, as a result, facilitates human cooperation (Sosis and Alcorta 2003). Nothing in this explanation makes any causal reference to God. So, while the existence of God is not conclusively disproved, a debunker could argue that this explanation still undermines the rationality of theism. We will look more closely at such arguments in chapter 9.

In recent years, a growing number of philosophers of religion have focused on the question of whether or not evolutionary and cognitive explanations of religious belief can support debunking arguments against God’s existence (e.g., the essays collected in Schloss and Murray 2009). Perhaps unsurprisingly, theistic authors have argued that such explanations do not undermine theism (e.g., Visala 2011), or even that they provide support for theism (e.g., Barrett 2011), whereas nontheists suspect that these approaches debunk or are at least problematic for theism (e.g., Bering 2011). In this book, we will concentrate mostly on the first type of intersection between natural history and natural theology, namely what the sciences of the mind can tell us about intuitions that underlie natural theology. However, as we will see, understanding better how natural theology relies on stable human cognitive capacities will have implications for the rationality of natural theological arguments as well.

There is also a broader metaphysical consideration of why we can expect natural theology and natural history of religion to converge. Those who assume that metaphysical naturalism is the correct worldview, that is, that there is no God, would still need to explain why it is that intuitions about design, causality, agency, beauty, morality, and testimony persistently lead people to infer the existence of God. Why are design arguments compelling if there is no cosmic designer? Why do humans draw a connection between human moral intuitions and divine moral commands if there is no God who instilled these moral intuitions in us? A plausible explanation is that such inferences draw upon deep-seated human psychological dispositions. Hume recognized this in his Dialogues, where Cleanthes (the proponent of natural theological arguments for theism) queries Philo’s unflinching use of reason to attack natural theological arguments. Philo responds as follows:

I must confess, replied Philo, that I am less cautious on the subject of natural religion than on any other; both because I know that I can never, on that head, corrupt the principles of any man of common sense; and because no one, I am confident, in whose eyes I appear a man of common sense, will ever mistake my intentions. … A purpose, an intention, a design, strikes every where the most careless, the most stupid thinker; and no man can be so hardened in absurd systems, as at all times to reject it. (Hume 1779, 228)

This passage, commonly referred to as Philo’s confession, has received much attention in recent Hume scholarship (e.g., Goodnick 2012; Hardy 2012). One way to interpret it is that Hume thought that humans spontaneously see design, which leads them to posit the existence of a designer. As we shall see in chapter 4, metaphysical naturalists today can explain this propensity as the result of natural selection. If metaphysical naturalism is correct, inferring God from design, causality, moral judgments, beauty, and testimony are mistakes, misapplications of intuitions that have evolved to function in different domains.

By contrast, under a theistic worldview, natural theological intuitions can be interpreted quite differently, for under such a view (recently defended by Evans 2010), it seems plausible that God made the universe and designed the human mind in such a way that traces of his workmanship can be clearly discerned. Theists often invoke scriptural support for the view that God made his existence knowable not only to trained scientists and theologians, but to everyone who observes the world.

The heavens are telling the glory of God; and the firmament

proclaims his handiwork.

Day to day pours forth speech, and night to night declares

knowledge.

There is no speech, nor are there words; their voice is not heard;

yet their voice goes out through all the earth, and their words to

the end of the world. (Psalm 19:1–4)¹

For what can be known about God is plain to them, because God has shown it to them. Ever since the creation of the world his eternal power and divine nature, invisible though they are, have been understood and seen through the things he has made. So they are without excuse; for though they knew God, they did not honor him as God or give thanks to him, but they became futile in their thinking, and their senseless minds were darkened. (Romans 1:19–21)

Appeals to scripture fall outside of the scope of natural theology, but they are often used to justify its practice (e.g., Sudduth 1995). Theologians like John Calvin ([1559] 1960, book 1) have interpreted these scriptural passages as indicating that our ability to recognize God’s handiwork (i.e., to engage in natural theology) is reliably connected to God’s existence. Interestingly, they treat natural theology not as an arcane endeavor that is remote from everyday reasoning, but propose that discerning God’s handiwork is something that we do spontaneously and that is not dependent on a prior assumption of theism. After all, if Paul believed that this discernment was dependent on prior theistic belief, he would not have thought unbelievers were without excuse.

The metaphysical worldview one adopts has significant ramifications for one’s conceptualization of the intersection between cognitive science and natural theology. If metaphysical naturalism is right, the intuitions that underlie natural theology are incorrect; if theism is right, they are correct. Nevertheless, investigating the cognitive basis of natural theological arguments can be pursued largely independently from either of these worldviews. Even if one adopts a theistic worldview, according to which God designed the world and human cognition in such a way as to make himself knowable, it is still worthwhile to have a detailed causal account of this. Likewise, within a nontheistic framework, it is interesting to explain the enduring intuitive appeal of natural theological arguments by looking at stable features of human cognition.

Throughout this book, we will take moderate naturalism as a methodological assumption. Thus, when investigating the cognitive basis of intuitions in natural theology, we will not adopt metaphysical naturalism, which holds that there are no supernatural entities, nor will we assume a metaphysical theism, which takes the existence of God as a given. Moderate naturalism is neutral with respect to metaphysical assumptions. Alvin Goldman defines it as follows:

Moderate naturalism

(A) All epistemic warrant or justification is a function of the psychological (perhaps computational) processes that produce or preserve belief.²

(B) The epistemological enterprise needs appropriate help from science, especially the science of the mind. (Goldman 1999, 3)

Our chief help in our investigation of the cognitive basis of natural theology will be the cognitive science of religion, which investigates the cognitive processes that underlie religious beliefs. Because moderate naturalism is not committed to either theism or metaphysical naturalism, the reasonableness of intuitions that underlie natural theology cannot be assessed only by considering their psychological origins. For this, we will require additional assumptions about the relationship between the psychological origin of a belief and its justification. Throughout this book we will consider these assumptions as well.

What Is Natural Theology?

Natural theology is a branch of theology that examines the existence and attributes of God (or the gods, in polytheistic traditions) without reliance on special revelation. As a starting point, it takes the world of our ordinary experience (i.e., general revelation), and considers this in a systematic, reasoned way to link it to another, asserted reality. It is often contrasted with revealed theology, which depends on revelation through scripture and religious experience. Natural theologians set out to learn something about God, for example, whether or not there is a God, and what properties he has (the divine attributes), using ordinary experience and reasoning. In this broad sense, natural theology is also known as philosophical theology.

Within natural theology, several approaches can be outlined. The best-known and best-developed strand of natural theology is concerned with formulating arguments for or against the existence of God, such as the cosmological and moral arguments. A second strand focuses less on the world and more on the nature and structure of human cognition, in particular on the nature of human desires and beliefs. It regards the human mind as oriented toward God. The common consent argument (see chapter 9) and C. S. Lewis’s argument from desire (see chapter 7) are examples of this. A third project is concerned with outlining a theology of nature, which does not set out to infer the existence of God but, rather, aims to understand and interpret the natural world under the assumption of his existence. For instance, the molecular biologist Kenneth Miller (2007), the geneticist Francis Collins (2007), and the theologian John Haught (2000) paint theistic pictures that take into account evolutionary biology.

Natural theology is not restricted to particular religious traditions. Although many of its practitioners were and are monotheists, some polytheistic religions, such as those from India and ancient Greece, also had flourishing natural theologies. Since the seventeenth century, there has been an established tradition of atheist and agnostic natural theology as well (e.g., Hume, Voltaire) that continues to this day, especially with work on the problem of evil and on divine hiddenness (e.g., Trakakis, Schellenberg).

What constitutes the enduring appeal of natural theology across times and cultures? How can it be linked to religious beliefs and practices? Some authors (e.g., Philipse 2012) have argued that one should engage in natural theology before accepting any religious belief because one must first establish through argument and conceptual analysis whether particular religious beliefs are reasonable before one can even begin to adopt or reject them. Whether individual believers are under some form of epistemic obligation to ground their beliefs in natural theology is a matter of enduring philosophical debate. Reformed epistemologists argue that one is entitled to hold religious beliefs in the absence of any positive arguments in their favor (e.g., Plantinga 1993), whereas other authors propose that faith is an attitude that is cognitively and epistemically distinct from belief (e.g., Audi 2011).

Regardless of that, few people are religious believers or atheists because they are swayed by natural theological arguments. Most religious practice does not engage with and is independent from natural theological considerations. Yet natural theology has, as Allister McGrath (2011, 18) puts it, a persistent habit of returning, even when its death notice has been extensively and repeatedly published. Today, a large part of philosophy of religion (especially in the analytic tradition) focuses on natural theological themes such as arguments for the existence of God, whether God’s existence is compatible with moral and natural evil, and the relationship between human free will and divine omniscience. The idea that nature can point us toward some transcendent reality remains a fascinating one. Public debates and lectures on natural theology gather widespread attention, for example, between the former Anglican archbishop Rowan Williams and the evolutionary biologist Richard Dawkins.³ Natural theological arguments are discussed on numerous atheist and theist blogs and in other popular media. This public attention is remarkable, especially if we consider that natural theological arguments do not play a major role in the motivation to adopt or maintain religious belief.

The history of natural theology in the West can be traced to ancient Greek philosophy, in particular to the argument from design. In spite of the widespread appeal to teleology (purposiveness) to infer the existence of the gods, formal arguments from design remained relatively rare throughout ancient philosophy. The earliest Western design argument is attributed to Socrates, recorded in Xenophon’s ([4th c. bce] 1997) Memorabilia (55–63; 299–309). Socrates argued that there are two possible explanations for how living things are brought into being: design and chance. It is clear that living beings exhibit teleology. Products of chance typically do not exhibit teleology, unlike products of design, which often do. Therefore, that which produced living beings did so by design. Later on, Roman Stoic philosophers such as Cicero argued that the orderliness of the world provided strong evidence for the existence of the gods (see chapter 4). In his review of creationism in antiquity, David Sedley (2007) attributes the emergence of natural theological arguments in the ancient world to the rise of atomism, a competing, nontheistic worldview. According to atomism, as espoused by Democritus and Lucretius, the apparent design features came about by chance: long ago, chance produced a variety of life forms, most of them unviable but some of them viable. The living forms today are descendants of these fortuitous results of a blind trial-and-error process. Atomism provided a plausible alternative to creationism. As a result, theism was no longer the default position, and theists such as Socrates and Cicero felt obliged to provide explicit arguments that outlined a positive case for it.

This dialectical function of natural theology can also be discerned in non-Western traditions (see De Cruz 2014 for a detailed treatment). For instance, Hindu natural theologians formulated design and cosmological arguments as a reaction to nontheistic philosophical schools that included materialism, atomism, some varieties of Buddhism, and Sāmkhya, an atheist form of evolutionism. These views threatened a developing creationist form of Hinduism, according to which Brahman is the personal creator of the world. Although theistic authors like Śaṅkara and Udayana thought that scripture was authoritative and superior to reason, they still felt compelled to go against these schools by using natural theological arguments because proponents of these movements did not accept their interpretation of scripture or even rejected scripture altogether (Brown 2012, chapters 2–4).

Western natural theology became prominent again during the Middle Ages, first with Islamic philosophical theologians such as al-Farabi, Ibn Sīnā (Avicenna), and Ibn Rushd (Averroes), and somewhat later with Christian authors including Anselm, Duns Scotus, Thomas Aquinas, and William of Ockham. Many of these authors were influenced by the natural philosophy of Aristotle, which became known through Arabic translations. For instance, Aristotle’s concept of a prime mover, a first cause, became important in the development of cosmological arguments in medieval Christianity and Islam. This period saw the development of a variety of sophisticated natural theological arguments.

In the seventeenth and eighteenth centuries, the emergence of the natural sciences led to a thorough reconsideration of the project of natural theology. Devastating religious wars throughout the sixteenth and early seventeenth centuries brought about disenchantment with ecclesiastic authority and organized religion. Since natural theology is concerned with empirical observation and reason, its methodology overlaps to some extent with that of the natural sciences. It became clear that the sciences contradicted scripture, for instance, in the calculation of the age of the earth, its cosmology (heliocentric versus geocentric), and in its model of the origin of species. These scientific challenges to scriptural accuracy put revealed theology under pressure.

Another source of tension for revealed theology was historical biblical criticism, which developed and flourished in eighteenth-century Enlightenment Europe. For the first time in Christian history, the Bible was not seen as the inerrant word of God. Already during the patristic period and beyond, some authors (e.g., Augustine [416] 2002) favored a metaphorical interpretation of some biblical passages that seemed inconsistent with factual knowledge of the world. However, only in the early modern period did a historical view arise of the Bible as the result of a gradual, historical genesis with multiple authors. Biblical scholars began to investigate their historicity through textual analysis (e.g., the internal contradictions and inconsistencies between biblical texts) and by examining the historical and cultural contexts in which these books were recorded.

In this intellectual climate, natural theology became an attractive enterprise. Unlike other forms of theology, it could be conducted independently from scriptural sources and from ecclesiastic authority. But there were also positive reasons for its popularity in the early modern world, particularly the emerging mechanistic worldview, which made analogies between divine and human craftsmanship natural to draw. In England, natural theology flourished between the end of the seventeenth and the middle of the eighteenth centuries. Many natural theologians were natural philosophers (the closest term then for what we now call scientists), such as Robert Boyle and John Ray (see McGrath 2011 for a detailed overview). In the Netherlands, too, natural philosophers such as Bernard Nieuwentijt and Antonie van Leeuwenhoek were impressed by the orderliness and apparent design of the natural world, offering explicit arguments from design.

Many authors have assumed that the early modern project of natural theology collapsed as a result of scientific discoveries, in particular, the theory of natural selection, which provided a viable explanation for design without invoking a designer. Steve Stewart-Williams (2010, 62, n. 16) echoes this familiar sentiment when he writes, The view that faith rather than reason is the path to true knowledge of God was held long before Darwin promulgated his theory. But the theory provided all the more reason to jettison reason and evidence, and to base one’s beliefs entirely on faith (i.e., on nothing).

There is little historical evidence for this purported role of Darwinism in the destruction of reasoned religious belief. Natural theology continued until well into the early twentieth century. Many theistic authors, such Asa Gray and Frederick Tennant, reacted favorably to Darwin’s theory and sought to incorporate it within their natural theology (see Bowler 2007 for a historical overview). Moreover, philosophical criticisms by Kant and Hume predate Darwin by nearly a century. The design argument, the flagship argument of early modern natural theology, came under attack from naturalistic theories such as the pre-Darwinian transmutation theories that were developed in France, Germany, and the United Kingdom. For example, Jean-Baptiste Lamarck (1809) proposed that transmutation of species occurred through the transmission of acquired characteristics. These ideas enjoyed wide currency across Europe, where they were translated within a few years of publication in several European languages and were further developed by authors in Italy and Belgium. When William Paley wrote his Natural Theology, this work already reflected an ongoing debate on the viability of the natural theological project (see chapter 4). It was published at the tail end, not even in the thick of the debate.

A more plausible reason for the decline of natural theology in the late nineteenth century was the incipient influence of methodological naturalism in the sciences. While seventeenth-century natural philosophers still appealed to divine intervention, nineteenth-century scientists adhered more and more to a strict methodological naturalism. This growing popularity of methodological naturalism was partly due to the fact that it worked well. For instance, while Newton still required God to intervene in the movement of heavenly bodies, improved calculations made the appeal to God redundant. However, methodological naturalism was also successful because it was promoted by powerful lobbyists such as Thomas Henry Huxley and other members of the X-Club, a dinner club that aimed, among other things, to excise all appeals to supernaturalism from scientific discourse. In this way, they successfully lessened the competition from amateur-clergymen scientists for posts in scientific institutions and societies (Garwood 2008). This intellectual climate was not congenial to natural theology.

The situation for natural theology became even bleaker by the early twentieth century, when the epistemology underlying science stressed testability and verifiability as essential criteria for empirical claims. This not only widened the gap between natural theology and science but also cast serious doubts on the intellectual legitimacy of natural theology. Since its claims are not verifiable and not empirically testable, according to the logical positivists of the early twentieth century they were either meaningless or false. Logical positivism and its verification principle collapsed in the second half of the twentieth century; the verification principle failed to describe actual scientific practice and could not be coherently applied to itself—the claim that every claim has to be verifiable is itself unverifiable. The newly emerging epistemology was friendlier to natural theology and to philosophy of religion in general. These fields are currently experiencing a revival, with intensive discussion on topics such as the relationship between theism and evil, the nature of divine attributes, and whether or not God knows what people will freely do. Most prominent contemporary practitioners of natural theology, such as Richard Swinburne, Eleonore Stump, and William Lane Craig, are not theologians but philosophers.

Natural theology is conducted in dialogue with naturalistic, philosophical, and scientific worldviews. When religious beliefs are universal and the existence of God (or the gods) is considered obvious, there is little incentive to argue for his existence. By contrast, naturalistic worldviews and ways of thinking prompt the need for explicit and coherent arguments for or against God’s existence. Another reason for the close interrelatedness between the sciences and natural theology is an overlap in their basic ways of inquiry: both reason from observation of the empirical world. As we will see in chapters 4, 5, and 8, natural theologians frequently appeal to science, for instance, about the goal-directedness in biological traits (design argument), the big bang theory (cosmological argument), and the concept of scientific laws (argument from miracles). As this book shows, the results of cognitive science of religion are a novel source of inspiration for natural theology. Natural theology, unlike most other forms of theology, does not explicitly presuppose the existence of God. Ideally, natural theological arguments should be intelligible regardless of one’s metaphysical assumptions by appealing to observations and intuitions shared by all. In order to be successful, the intuitions to which natural theological arguments appeal should thus be widely shared or at least prima facie plausible. In this book, we will examine what makes these intuitions plausible by considering stable features of human cognition.

What Is Cognitive Science of Religion?

Religious beliefs and practices have been, and continue to be, widespread. About 85 percent to 90 percent of the world’s population believes in one or more gods (Zuckerman 2007). Most people worldwide also engage in religious practices at some point in their lives, such as attending weddings, funerals, or visiting religious devotional spaces. Anthropologists regard religion as a universal element of human culture, at least since Edward Burnett Tylor (1871) wrote about Australian aboriginal myths and rituals. He defined religion as beliefs and practices dealing with ancestors, spirits, and other supernatural agents. In the archeological record, evidence for religious belief dates back to at least 40,000 years ago, with imagery of imaginary beings such as sculptures that represent therianthropic (e.g., half-human, half-lion) beings. More tentatively, deliberate burials by Homo sapiens and Homo neanderthalensis may point to belief in an afterlife, which would push back the first evidence for religious belief to about 110,000 years ago. But these early burials do not contain uncontested grave gifts or other signs that warrant inference to such beliefs. From about 27,000 to 26,000 years ago, we see more definite evidence of intentional burial, including grave gifts in the double-child burial at Sungir, Russia (Kuzmin et al. 2004).

Although there is no generally accepted definition for religion, a suitable starting point is its etymology, the Latin religare, to bind or unite. In this view, religions are practices and beliefs that bind communities of people and that link them to a supernatural realm. By this broad anthropological working definition, religion is universal in the same sense that, for instance, music and fire-making are human universals.⁴ That is to say, although not all humans have religious beliefs, features of human behavior that are regarded as religious (e.g., belief in supernatural beings, engaging in rituals) are present in all human cultures, and almost everyone has some knowledge of one or more particular religious beliefs and practices, such as the dates and meanings of religious festivals and the properties of supernatural beings.

In the past, the cross-cultural prevalence of religious beliefs formed the main premise of the consensus gentium (common consent) argument, which was espoused by authors such as Cicero, John Calvin, and Pierre Gassendi. Roughly speaking, the argument holds that widespread theistic belief constitutes strong evidence for God’s existence. The rise of secularism combined with an increased emphasis on individual critical thinking in philosophy and science has led to the demise of this argument (but see Kelly 2011). Nevertheless, the ubiquity of religious beliefs even in the face of well-developed naturalistic worldviews as, in particular, offered by the sciences remains a fact that requires explanation. As the sciences are committed to methodological naturalism, scientists cannot invoke—as the common consent argument did—God’s existence to explain the prevalence of religious beliefs. Thus, scientific approaches to religion do not assume God’s existence but instead look at natural features of human cognition and social organization to explain its prevalence.

The near-universality of religion has been a focus of intense scientific study. Anthropologists and sociologists traditionally explained religious beliefs and practices as purely cultural phenomena that help humans to make sense of the world and to organize their society (e.g., Durkheim 1915). This cultural layer was regarded as a superstructure that was completely independent from our evolved, biological nature. This treatment of culture as a separate entity