It’s difficult to imagine religion without the capacity to experience these emotional elaborations for the same reason it’s difficult to imagine close social groups without them: such an emotional palette binds us to one another at a visceral level. “Human solidarities are only possible by emotional arousal revolving around positive emotions – love, happiness, satisfaction, caring, loyalty – and the mitigation of the power of negative emotions, or at least some negative emotions,” says Turner. “And once these new valences of positive emotions are neurologically possible, they can become entwined with rituals and other emotion-arousing behaviours to enhance solidarities and, eventually, produce notions of power gods and supernatural forces.”

Not to jump ahead too far, but it’s important to understand how pivotal feeling is in the evolution of religion. As far as Darwin was convinced, there wasn’t any difference between religious feeling and any other feeling. “It is an argument for materialism,” he wrote in a journal entry, “that cold water brings on suddenly in head, a frame of mind, analogous to those feelings, which may be considered as truly spiritual.” If this is true, then that means the causes of religious feelings can be pinpointed and studied just like any other feeling.

Ritual

As selection worked on existing brain structures, enhancing emotional and interpersonal capacities, certain behavioural propensities of apes began to evolve. Some of the propensities that Turner lists as already present in apes include: the ability to read eyes and faces and to imitate facial gestures; various capacities for empathy; the ability to become emotionally aroused in social settings; the capacity to perform rituals; a sense of reciprocity and justice; and the ability to see the self as an object in an environment. An increase in the emotional palette available to apes would, according to Turner, result in an increase in all of these behavioural capacities.

Though many if not all of these behaviours have been documented in apes, I want to concentrate on two of them – ritual and empathy – without which religion would be unthinkable.

In archival footage, primatologist and anthropologist Jane Goodall describes the well-known waterfall dance which has been widely observed in chimpanzees. Her comments are worth quoting at length:

When the chimpanzees approach, they hear this roaring sound, and you see their hair stands a little on end and then they move a bit quicker. When they get here, they’ll rhythmically sway, often upright, picking up big rocks and throwing them for maybe 10 minutes. Sometimes climbing up the vines at the side and swinging out into the spray, and they’re right down in the water which normally they avoid. Afterwards you’ll see them sitting on a rock, actually in the stream, looking up, watching the water with their eyes as it falls down, and then watching it going away. I can’t help feeling that this waterfall display or dance is perhaps triggered by feelings awe, wonder that we feel.

The chimpanzee’s brain is so like ours: they have emotions that are clearly similar to or the same as those that we call happiness, sad, fear, despair, and so forth – the incredible intellectual abilities that we used to think unique to us. So why wouldn’t they also have feelings of some kind of spirituality, which is really being amazed at things outside yourself?

Goodall has observed a similar phenomenon happen during a heavy rain. These observations have led her to conclude that chimpanzees are as spiritual as we are. “They can’t analyse it, they don’t talk about it, they can’t describe what they feel. But you get the feeling that it’s all locked up inside them and the only way they can express it is through this fantastic rhythmic dance.” In addition to the displays that Goodall describes, others have observed various carnivalesque displays, drumming sessions, and various hooting rituals.

The roots of ritual are in what Bellah calls “serious play” – activities done for their own sake, which may not serve an immediate survival capacity, but which have “a very large potentiality of developing more capacities”. This view fits with various theories in developmental science, showing that playful activities are often crucial for developing important abilities like theory of mind and counterfactual thinking.

Play, in this evolutionary sense, has many unique characteristics: it must be performed “in a relaxed field” – when the animal is fed and healthy and stress-free (which is why it is most common in species with extended parental care). Play also occurs in bouts: it has a clear beginning and ending. In dogs, for example, play is initiated with a “bow”. Play involves a sense of justice, or at least equanimity: big animals need to self-handicap in order to not hurt smaller animals. And it might go without saying, but play is embodied.