Dealing with Disgust
Humans evolved to feel disgust because those who experienced the emotion were more likely to avoid infections (and therefore survive to produce successful offspring). Disgust works by assigning a strong negative modifier to things that would otherwise be positive stimuli—things like food, which normally we’d want to consume, but which is really important to avoid once it has become spoiled or otherwise contaminated.
As we mentioned ad nauseam in The Pragmatist’s Guide to Sexuality, evolution is a cheap programmer and it will reuse existing systems whenever possible. For this reason, when evolution “needed” a negative modifier for other categories of things likely to appeal to humans, the disgust modifier came into play. This can be seen in the disgust the average human feels around having sex with the same gender or a parent. While sex in general is appealing, evolution historically favored those whose disgust systems came to activate in response to non-reproductive mating that increases risk of disease transfer (such as gay sex) and negative genetic repercussions (such as incestuous sex).
While this development in isolation isn’t so troublesome, the fact that the human brain’s morality system also seems to have hijacked the disgust system causes a lot of grief. Why? Because the average human working on autopilot will assume a thing is immoral if it elicits a disgust response.[[33]](#_ftn33) In other words, if you show someone a video of a 25-year-old voluntarily having sex with an 80-year-old—or a person eating their own poop—they will tell you the act is immoral even if they cannot explain exactly what makes the act immoral.
This disgust-morality connection isn’t optimal because while things like gay sex may not lead to reproduction (and therefore not be all that favored from an evolutionary standpoint), there is no inherent reason why it should be categorized as immoral. If people didn’t instinctually regard things that commonly disgust them as immoral, we imagine that many fewer cultures would be homophobic, for example. It only makes logical sense for a culture to be homophobic if (a) It values population growth (b) most population growth comes from monogamous pairings rather than, say, harem-style arrangements, and (c) old-fashioned sex is the only way to produce humans.
In addition to explaining otherwise-confusing traditions around shunning gay people and menstruating women, this phenomenon may also explain some very strange religious prohibitions like Shatnez (the prohibition in Judaism against mixing wool and linen). This might have been the result of the childhood innate disgust response triggered when things mix and thus cross-contaminate (think of the kid who won’t eat his dinner after his peas touch his mashed potatoes). It could be that someone important in history felt a disgust reaction like this, did not know where it came from, and assumed mixing certain things was immoral.
Some cultivars choose to lean into this connection by using people’s innate disgust with specific things to try to emotionally prove the cultivar is “pure and accurate.” Alternatively, you can decide that finding disgust in things as a sign of immorality is itself immoral because it is not based on logic. You can probably guess where our cultivar stands given that we find all emotionally-motivated decisions and categorizations to be immoral. In fact, we see this odd creep of the disgust system—something most likely originally evolved to just stop us from eating festering food—as a great example of why we can’t universally trust emotions. Emotions that drove survival thousands of years ago may very well kill us in today’s strikingly different landscape.