The evolution of atheism

Nicholas C. DiDonato

Typically, when researchers study religion, they find that it brings various benefits to society: cohesion, cooperation, trust, etc. Religion evolved and persisted because of the gains religious cultures reaped. However, these findings implicitly seem to uplift religious people and make a puzzle out of atheists. If atheism (by implication) hurts the fabric of society, why did it evolve? What’s the evolutionary purpose of atheists? Political scientist Dominic Johnson (University of Edinburgh), rather than offering a definitive answer, instead suggests no less than ten possible hypotheses.

Before delving into what he takes as ten plausible hypotheses for why atheism evolves, Johnson must first define what he means by “atheism” and an “evolutionary explanation.” Johnson defines “atheism” as “the phenomenon of individuals who do not hold religious beliefs, such as a belief in a supernatural agent.”

As for his working definition of “evolutionary explanation,” he follows Niko Tinbergen’s “four causes”: phylogeny, proximate mechanism, development, and function. An evolutionary explanation, then, considers all four of these causes. First, phylogeny asks: what is the evolutionary history and ancestral state of the feature to be explained? In the case of atheism, at some point humanity’s evolutionary history, non-belief in religion was the ancestral (i.e., default) state. A problem arises for the evolution of atheism because the benefits of religion had so much strength that they reversed this state.

Second, proximate mechanism looks for the physiological mechanisms that caused the feature to be explained to occur. Third, development asks how the feature to be explained develops from birth to maturity (i.e., in the life cycle of an organism). For atheism, children believe in supernatural agency by default and may become atheists as they grow older. Finally, function seeks the evolutionary purpose of the feature to be explained.

With these four causes in mind, Johnson moves on to analyze ten hypotheses accounting for the evolution of atheism. First, he personally favors the null hypothesis, that is, atheism has no evolutionary effects at all. Evolution relies on variation, and non-belief simply represents a variation of belief. Atheism does nothing more than attest to the variety of belief put forth in the normal course of evolution.

Second, Johnson considers the hypothesis that “There are no atheists.” Given the human brain’s natural tendency to see supernatural agency at work, so-called “atheists” can only condition themselves against this biological default to a certain extent. In fact, when tested, they too display signs of supernatural thinking (they of course deny this). Perhaps humanity’s supernatural agency detection rests so deeply embedded in the human brain that no one can remove it despite the best of efforts. Furthermore, atheists’ moral and behavioral norms reflect those of their religious community (e.g., Christian values in the West, Islamic in Saudi Arabia, Hindu in India, etc.). While their beliefs are atheistic, their actions betray a religion.

Third, the “unnatural variation” hypothesis states that atheism arose recently and unnaturally because of increased (especially philosophical and scientific) education. Nature did not create atheism—people did.

Fourth, the “frequency dependence” hypothesis postulates that, given the right proportion of believers to atheists, evolution selects for atheism. If too few believers or too many atheists exist, then atheism will cease to grow. For instance, since religion encourages cooperation but also demands certain sacrifices (e.g., time, money), a small pocket of atheists may exploit this situation by enjoying the benefits of a cooperative society but not expending any of the costs of religion. In other words, atheists freeload off of believers. Evolutionary game theory indicates that a society cannot sustain too many freeloaders, and this caps the number of atheists that can exist at the same time in a particular society.

In a related theory, the exploitation hypothesis conjectures that religion exploits people and so atheism evolved for the leaders of a society so that they do not have to bear the costs of the very religion they use to control the masses.

Sixth, Johnson analyzes the “ecological contingency” hypothesis. Here, the evolutionary selection of atheism or religious belief depends on the socio-ecological context. Some contexts select for atheism while others select for belief. As these contexts change across time and place, society will have acquired a mix of atheists and believers.

The seventh hypothesis treats atheists as catalysts. Religious identity only makes sense against a contrast of non-identity. In other words, the perceived benefits and costs of religion only matter when they differentiate an in-group from an out-group. If everyone belongs to the in-group, identity disappears. Atheists, then, actually facilitate belief by incentivizing believers to signal their religious identity to each other.

Similarly, the eighth hypothesis, “bolstering,” suggests that the presence of atheists bolsters religious doctrine. Atheists antagonize believers, forcing them to secure the grounds of their beliefs against the atheists’ criticism. This results in a stronger, more well-reasoned belief structure. At the same time, the threat of atheism may result in higher religious education. Of course, atheists may convert believers to their side and so hurt religion. Thus, the bolstering hypothesis only works if atheists antagonize but do not successfully convert believers. Historically speaking, every human society has had religion, and therefore one may reasonably conclude that atheism has in fact primarily succeeded only in bolstering religious doctrine.

Ninth, counter to the bolstering hypothesis, the restraint hypothesis theorizes that atheism forces religious doctrine to moderate. As religious belief grows extreme, atheists step in, reject it, and thereby force religious leaders to tone it down. Extreme religious doctrines could damage society, and atheism acts as a force of correction, ensuring religion does not become harmful. Atheism may continue to spread until the religious leaders end their most dangerous practices.

The tenth and final hypothesis treats atheism as a religion. Perhaps mildly appalled at the evangelical rigor of the “new atheist” movement, Johnson observes that “the behavior of serious atheists seems to resemble the behavior of believers.” He quotes David Sloan Wilson on the similarities between the new atheism and religion: “a polarized belief system that represents everything as good, good, good or bad, bad, bad (‘how religion poisons everything’), the unquestioned authority of its leaders, and even the portrayal of bad ideas as like demons (parasitic memes) that need to be cast out (‘breaking the spell’).’’ Atheists share a worldview, value system, rival (usually a religion), and a belief in “the superiority of their beliefs.” As Johnson puts it: “…(many) atheists are a collection of like-minded individuals who identify themselves by certain beliefs about the world, who differentiate themselves from people with different beliefs, and who stick together. They may, therefore, be gleaning the same adaptive benefits that religious believers do from membership of a group with shared values and beliefs.” Johnson quickly notes that this hypothesis tends to explain atheism as a contemporary phenomenon rather than a product of a long evolutionary past.

From the start, while admitting he prefers the null hypothesis, Johnson did not intend to argue for any particular hypothesis. Few of the hypotheses exclude each other, meaning that many more possible hypotheses exist when combined in various ways. At bottom, though, remains the historical question of why atheism actually did evolve. What reallycaused it? For the answer to that, God only knows.

For more, see “What are atheists for? Hypotheses on the functions of non-belief in the evolution of religion” in the journal Religion, Brain, and Behavior.