1 Introduction: Cognitive Science of Religion and Its Philosophical Implications Helen De Cruz and Ryan Nichols Cognitive science and experimental philosophy Philosophy of religion examines questions about the existence and nature of God and other religious entities and about religion as a cultural and cognitive phenomenon. Until the early modern period, philosophy of religion was one of the central areas of philosophical inquiry. Prominent philosophers of religion, such as Thomas Aquinas, believed that there were three sources on which we could rely in answer to questions about God and religious matters: our own reasoning skills, divine revelation (e.g., scriptures), and what other thinkers have said (tradition). These tools are still used in contemporary philosophy of religion, which places more emphasis on reasoning than on scriptures or tradition. Commonly philosophers rely on reasoning from the armchair, that is, using their own intuitions in conceptual analysis, argumentation, and thought experiments. However, some philosophical branches, such as epistemology and philosophy of mind, have engaged increasingly with methods and results from the empirical sciences. Using a quantitative analysis, Knobe (2015) found that the majority of works by philosophers of mind from the 1960s to the 1990s relied on armchair reasoning, whereas of the papers published between 2009 and 2013, only a minority relied purely on armchair methods. There are two ways in which philosophy can be empirically informed. It can be informed directly, by testing philosophical claims through experimental techniques (experimental philosophy). It can also be informed indirectly, by relying on the empirical findings of others (e.g., published studies in psychology, cosmology, or evolutionary biology) to support philosophical claims. Philosophical work that relies on scientific studies of other researchers is sometimes called “empirical philosophy” (Prinz 2008). This distinction between 9781474223843_txt_rev.indd 1 8/25/15 6:45 PM 2 Advances in Religion, Cognitive Science, and Experimental Philosophy experimental and empirical philosophy might blur as experimental philosophy matures and comes closer to cognitive psychology in its methodology, but for now, it remains useful. Experimental philosophy is a new and still controversial branch of philosophy, spanning diverse areas such as epistemology, moral philosophy, and metaphysics. Many experimental philosophers examine whether the intuitions of professional philosophers match those of nonphilosophers by employing experiments and surveys (Alexander et al. 2014). For example, Gettier cases (1963) provide evidence that knowledge is not merely justified true belief: when someone comes to believe it is 3 pm by reading her watch, and it is really 3 pm but that is a lucky coincidence as her watch has stopped, her belief is not knowledge. This is so even though her belief is both true and justified. Experimental philosophers (e.g., Weinberg et al. 2001) have found that this intuition is not universally shared among laypeople, and that there might be gender and ethnic differences in response to Gettier scenarios (Buckwalter and Stich 2014). However, in follow-up studies, this effect failed to replicate (see Kim and Yuan 2015, and Nagel et al. 2013 for a methodological critique and reply). More recently, experimental philosophers have examined whether philosophers might enjoy expert knowledge not available to laypeople. For instance, Schwitzgebel and Cushman (2014) investigated whether professional ethicists might be less susceptible to ordering and framing effects in moral dilemmas compared to non- ethicists and laypeople. Philosophers were as susceptible as laypeople to such distorting effects. Consider trolley case vignettes. Participants are told to imagine a trolley speeding out of control, destined to kill several people who are tied to the track. Participants are commonly asked whether they would be willing instead to do one or the other of several options. They might be asked if they are willing to flip a lever to send the trolley down a different track that will kill only one person; willing to physically push with their hands a fat person over the railing and onto the track stopping the trolley but killing the fat person; or willing to push the fat person over the railing by using a pole to do so, etc. In the particular version of this experiment given to philosophers, they judged trolley scenarios more as equivalent if pushing a person off a bridge was presented first than if pulling a lever was presented first. In other words, philosophers were biased by ordering effects just like laypeople. The expertise hypothesis, which holds that philosophers would be less biased, is thus not empirically confirmed (see De Cruz 2015, Rini 2015, for analyses, and Schwitzgebel and Rust 2015 for a meta-analysis). Empirical philosophy significantly predates experimental philosophy and can be traced back to early modern philosophers such as Hume, Reid, and Locke. Although these authors could not rely on controlled experimental results, they 9781474223843_txt_rev.indd 2 8/25/15 6:45 PM Introduction 3 were nevertheless able to use less systematic empirical observations to test philosophical problems. For instance, Molyneux’s problem (incorporated in Locke [1689] 1979) asks whether a person who was congenitally blind but could now see would be able to tell a cube from a sphere by sight alone. This was thought to have important implications for two major philosophical theories of the time: Rationalism and Empiricism. Natural philosophers in the eighteenth century believed that if a blind person newly given sight were to successfully visually discriminate between a cube and a sphere without touching those objects, then Rationalism must be true. (Their reasoning had to do with the unity of innate ideas across multiple sensory modalities.) Empiricists, however, typically predicted that such a person would not be able to discriminate between a cube and a sphere, or, if such a person could, it would only be under biased experimental conditions (see Nichols 2007, ch. 9, for this story). Philosophers like Diderot examined studies of patients with cataracts who were treated and visually presented with objects to draw conclusions about Molyneux’ problem (see Degenaar 1996). Adam Smith theorized about conditions of disuse in the region of the brain processing visual information in patients who were given sight later in life (Smith [1751] 1982, 161). The empirical tradition of analysis of the Molyneux problem continues to this day, for example, recently by Held et al. (2011), who studied the capacities of newly sighted patients in India to recognize shapes by sight. Empirical philosophy of religion dates to the eighteenth century, with authors like de Fontenelle and de Brosses, who, in the absence of careful observational fieldwork of anthropologists, used reports of religious beliefs, behaviors, and rituals from far-flung parts of the world. Today, the best known work from this period is Hume’s Natural History of Religion ([1757] 1988), which unified available data into a theory about the psychological origins of theism, rooting it in anthropomorphism and early polytheistic traditions. Empirical philosophy is gaining ground with the increasing influence of naturalism and naturalistic methods, where philosophy is regarded as continuous with the sciences. Two types of experimental input for the philosophy of religion: Cognitive science of religion and experimental philosophy of religion Philosophy of religion can benefit from two types of experimental input, cognitive science of religion and experimental philosophy, leading to empirical philosophy of religion and experimental philosophy of religion, respectively. 9781474223843_txt_rev.indd 3 8/25/15 6:45 PM 4 Advances in Religion, Cognitive Science, and Experimental Philosophy The cognitive science of religion (CSR) is a relatively new, multidisciplinary field of the study of religious beliefs and practices. CSR scholars hold that religious beliefs and practices are typically the result of evolved, ordinary cognitive biases and processes. A common dictum in CSR is that religion is natural. Naturalness is a polysemic concept denoting that religious beliefs are easy to acquire and that they easily spread through cultural evolution (e.g., Boyer 2001), that beliefs that commonly occur in religious belief systems, such as belief in a life after death, occur early in development (e.g., Bering 2006), and that acquisition of religious beliefs does not require high cognitive effort, unlike say, scientific concepts (McCauley 2011). CSR has a broad scope, investigating topics such as religious rituals (e.g., Liénard and Boyer 2006), belief in spirit possession (Cohen 2007), and the psychosocial effects of belief in Hell (Shariff and Aknin 2014). Although CSR focuses on the cognitive correlates of religious belief, there is a large body of research on closely related topics as well, such as the relation between religiosity and prosociality (e.g., Norenzayan and Shariff 2008). For example, belief in hell but not heaven is positively correlated with low rates of social crime, whereas belief in heaven but not in hell is positively correlated with high rates of social crime (Shariff and Rhemtulla 2012). Although religion seems to make people more prosocial, this could be caused by non-religious factors, such as concern for one’s reputation. Some experiments address such alternative explanations directly