Purity and Perception

You may think you don’t care about purity, but I’m here to convince you that you do—or at least you should. If you lean conservative or consider yourself spiritual, then words like purity and sanctity may already be part of your vocabulary. But for many—especially liberal and atheistic types—the concept of purity evokes the rituals of prescientific cultures, religious or totalitarian dogma, xenophobia, and puritanical attitudes towards sex. And for good reason. There is no question that a salvo of evils have been committed in the name of purity. The problem is that unthinkable acts have been committed under the banner of, well, pretty much every value imaginable (yes, empathy too).    

Purity’s tremendous power, as well as its notoriety, emanates from its relationship with the emotion of disgust. For many liberal-minded people, a display of disgust is tantamount to a moral failure, a blunder brought about by closed-mindedness and a lack of empathy.  In this narrative, disgust is often compared to our voracious appetite for sugar. When we were roaming about as hunter gatherers, the story goes, it was adaptive to consume whatever sugar we could get our hands on, because sugar was scarce and our next meal was a question mark. However, in times of plenty, our craving for sugar becomes maladaptive, and leads to obesity and disease. The same goes for disgust—when we were living in tribes and exposed to the elements, a sensitive disgust response would protect us from pathogens and parasites. But in the age of disinfectants, vaccines, and antibiotics, disgust is no longer necessary for survival. Instead, it is exploited by zealots and tyrants to pour kerosene on hateful rhetoric.

If this evolutionary story is true, shouldn’t we dispense with disgust? And if the goal is to outgrow disgust, shouldn’t we also nix the archaic notion of purity, which may be founded on the disgust response? Not so fast. According to Jonathan Haidt and his colleague’s Moral Foundations Theory, purity—along with its associated emotion of disgust—is one of the pillars of morality (although they term the foundation sanctity/degradation). Like the other pillars of morality (care/harm, fairness/cheating, authority/subversion, and loyalty/betrayal), a concern for purity is seen across cultures. But, interestingly, unlike most of the other foundations, a concern for purity—or the expression of disgust—is not seen in babies, toddlers, or non-human animals.

This is where a strange paradox emerges. On one hand, disgust is often condemned as a visceral instinct that may have once been central to our animal nature but must now be overcome. But on the other hand, the developmental, anthropological, and ethological research all seem to point to disgust being a uniquely human emotion. So, is purity an animal vice or a human virtue? Well, the jury is still out on that question. Like with most complex questions, the answer probably is—both. But even if we concede that purity was once a human virtue, is it really still relevant to the 21^st century?

You are what you consume   

We’ve all heard the phrase “you are what you eat”. Aside from serving as the slogan for many health food and diet campaigns, the phrase reminds us that we shouldn’t put just anything into our bodies. Many religions, cultures, and movements buy into this conception of food (kosher, halāl, transubstantiation). Paul Bloom suggests that “essentialism”—the idea that food carries an essence that is transferred to us when we consume it—contributes to many of our elaborate rules and rituals surrounding food. This may be the case. After all, how else could one explain the consumption of the body and blood of Jesus Christ in the form of a wafer? But what if we expand the phrase to include all forms of consumption?

“You are what you consume” highlights the way we fill our minds rather than our bodies. Do the people that we hang out with, the TV shows that we watch, the music that we listen to, and the social media that we scroll through shape who we are? Common sense tells us that they do and the science seems to support this intuition. As neurophysiological research on perception advances and proliferates, the brain is increasingly portrayed as a prediction machine. In the “predictive coding” account, perception is a “top-down” process, in which our brains draw on our vast reservoir of past experiences to generate best guesses of external reality. These predictions are then contrasted with the “bottom-up” signals streaming in through our senses. This iterative process of prediction and prediction error (the mismatch between the top-down and bottom-up information) informs both perception of the world and of ourselves. Have you ever seen an animal sprawled in the distance that turned out to be some leaves and twigs upon closer inspection? What about a spider scurrying in your periphery that was really a lurking shadow? If you have, you’ve experienced prediction error in real time. Your initial predictions were off-target, but your predictions were updated and a closer look cleared the confusion. 

One consequence of this “Bayesian brain” hypothesis (the predictive coding account of perception), is that it puts us in the driver’s seat. We are, in many ways, the architects of our experience.  As cognitive psychology and psychotherapy have been asserting for decades (and religions for centuries), we have the power to shape our perception. Our situation is similar to that of the Google search engine. Just as Google runs predictive algorithms to generate search suggestions, our brains run predictive algorithms to generate perceptive suggestions. The difference is that we can choose the data that we feed the algorithm, and in doing so, guide the suggestions that the algorithm spits out. In other words, by choosing what we consume, we are constructing the timbre of our reality. In a sense, we are fashioning the lens through which we see the world and ourselves.

Perhaps this is where disgust and purity can benefit perception. Our desire to remain untainted by disgusting images or thoughts is our desire to see the world through a certain moral, or humane, lens. In this light, disgust can be seen as the rudder steering us away from harmful input, like a firewall blocking threatening sites. It may be fun to subvert purity norms occasionally (like in games such as Cards Against Humanity or in comedy), but most of us crave to see the world through an ennobling lens, one in which human life is sacred and meaningful interactions are cherished.

In a recent podcast, Sam Harris described his experience of watching the first few episodes of Tiger King: “At a certain point I began to feel polluted by and somehow complicit in spectating upon obvious human misery.” In fact, Harris felt so polluted by the episodes that he chose not to finish the season. Still, in an earlier discussion with Jonathan Haidt, Harris explained how it is the humanist’s duty to transcend primal but ultimately pernicious emotions: “We have to get rid of our disgust circuitry that misfires in so many ways, leading us to condemn people for things that shouldn’t be considered moral infractions.” The prospect of excising outmoded emotions is a tantalizing one, especially when the very same emotions have bolstered the rallying cries for an endless list of crimes against humanity. But we must always ask ourselves—at what cost? How much of human nature can we discard without losing our basic humanity along the way?

Further Reading

Against Empathy by Paul Bloom

How Pleasure Works by Paul Bloom

Moral Foundations Theory: The Pragmatic Validity of Moral Pluralism by Graham et al.

Interoceptive inference, emotion, and the embodied self by Anil Seth