For me, the really interesting aspect of disgust and the associated contamination fears is that they show all the hallmarks of supernatural thinking.46 This is because they trigger psychological essentialism, vitalistic reasoning, and sympathetic magic. For example, sympathetic magic states that an essence can be transferred on contact and that it continues to exert an influence after that contact has ceased. This is known as the ‘once in contact, always in contact’ principle.47 Something you cherish can be ruined by coming into contact with a disgusting contaminant in exactly the same way. For example, the briefest touch of your food by someone you think is disgusting makes the dish unpalatable. There’s an old saying that a drop of oil can spoil a barrel of honey, but a drop of honey can’t ruin a barrel of oil. This is the negative bias that humans hold when it comes to contamination.48 We intuitively feel that the integrity of something good can be more easily spoiled by contact with something bad rather than the other way around.
However, it’s difficult to be reasonable about contamination once it’s occurred. It’s as if the contaminant has energy that can spread. For example, imagine that your favourite dessert is cherry pie and that you have the option of choosing between a very large slice and a much smaller piece. Unfortunately, your waiter accidentally touches the crust of the large slice with his dirty thumb. The same thumb that you just saw him pick his nose with. Which slice would you choose? Given the choice, most of us would opt for the smaller slice, even though we could cut off the crust where the waiter touched it and still end up with more pie. As far as we are concerned, the whole slice has been ruined – as well as our appetite.
THE WISDOM OF REPUGNANCE
Disgust affects more than just our attitudes toward the things we put in our mouths. It clouds our moral judgements too. Many people rely on disgust in deciding what they think is right or wrong. Leon Kass, the former chief ethical adviser to President George W. Bush, argued that disgust is a reliable barometer to what we should find morally unacceptable, the so-called knee-jerk response. In his essay ‘The Wisdom of Repugnance’, he makes the case that disgust reflects deep-seated notions and should be interpreted as evidence for the intrinsically harmful or evil nature of something.49 If you feel disgusted when you hear about some event, then that’s because it is wrong. The problem with this view is that what people find disgusting depends on whom you ask.
Consider incest between a consenting brother and sister. In most societies, brother and sister incest is regarded as disgusting. Why? What is wrong with two genetically related people having sex? We could argue that this response evolved because of the risks of inbreeding. For example, mating with your sibling is a genetic no-no, as there is an increased chance that any offspring would have genetic abnormalities. And yet if a brother and sister have consensual sexual intercourse in private so that no one would ever know, using birth control and basically avoiding any possible chance of pregnancy, we still consider such sex morally unacceptable. Then there are all the other weird things that people might get up to. Why is cleaning the toilet with the national flag or eating a chicken carcass you have just used for masturbation disgusting? These acts might be weird, but there is no intrinsic reason for why they are wrong.50What’s wrong with wearing a killer’s cardigan? In fact, people are often lost for words when trying to give reasons. They are morally dumb-founded, as the psychologist Jonathan Haidt says.51 By the way, just in case you wondered about the warped state of my own mind, these disturbing examples all come from Haidt’s work. So write to him if they upset you.
Biological explanations are too limited for explaining all the things we find disgusting. Rather, the answer must be some other mechanism that uses disgust responses for some other purpose. One possibility is that disgust works as a mechanism for social cohesion. To form a cohesive group we must have sets of rules, beliefs, and practices that define our group and that each member must agree to abide by. This is how one gang distinguishes itself from another. These are the moral codes of conduct found throughout the different cultures of the world. When these rules are violated, a taboo has been broken, and a negative emotional response must be triggered. The perpetrator must feel guilt, and the rest of us must punish that person. This is how justice works. The net effect is to strengthen the cohesion of the group.
Culturally defined taboos may engender social cohesion, but they are not based on any reason other than that they define the group. This is why those individuals who are happy to touch a killer’s cardigan are outsiders. By taking a behaviour and linking it to a visceral response, we can use disgust to control individual group members. We can also use disgust to ostracize others. In the next chapter, we examine how such essential thinking is at the root of bigotry directed towards people who some would rather keep at arm’s length because of their colour or social background. When we say the peasants are revolting, we mean it in a disgusted way. It provides the emotional reason for treating them the way oppressors do. We can treat others badly who do not share our values because it feels right. And why does it feel right? I think the answer is that a supersense of invisible properties operating in the world makes these feelings seem reasonable, and disgust is the negative consequence of violating our sacred values.
WHAT NEXT?
In this chapter we have looked at an emerging biological understanding of the world that depends on categorization based on outward appearances and inferred invisible properties. Our mind design seems set to look for patterns and deeper causal explanations for the different kinds of things we think exist in the living world. This process leads to spontaneous untaught concepts of essences, life energies and holistic connection. Many of these beliefs can also be found in ancient models of the natural world where hidden structures and mechanisms were thought to reflect a supernatural order in the universe.
While these intuitive concepts have true scientific validity to some extent, our naive way of thinking about them leads us to attribute additional properties that would be supernatural if true. For example, supernaturalism forms the basis of belief for those who advocate the sympathetic power of diluted potions and magical foods that share some resemblance to the affliction under question. In these situations, belief alone is sometimes sufficient to produce the desired result even though there is no active ingredient in the potion or food. Like the illusion of control discussed in chapter 1, believing that you will benefit is sometimes good enough.
Such beliefs also influence the way we see ourselves as members of a group. In particular, our supersense leads us to infer something essential and integral to the group that should not be violated or contaminated by outside influences. When this happens, we feel revulsion and disgust. These are emotional states triggered by mechanisms that exhibit many supernatural properties of sympathies, antipathies and spiritual contamination. In this way, our supersense operates to unite the group members by shared sacred values.