In her recent book entitled “That’s Disgusting,” Brown University psychologist Rachel Herz makes the case for understanding what makes human beings gag with revulsion. In short, her thesis is that what people find disgusting is “an unfolding and cognitive emotion” that protects us from dangers such as disease, contamination, and decomposition. So while disgust is culturally based, there is, nonetheless a seemingly universal revulsion at anything oozy, wriggly, putrid or moist.

It is an interesting thesis and one that supports the work of evolutionary psychologists who want to believe that all human behaviour is, at root, influenced by the way people are hard-wired to survive. Yet it is hard to imagine what, precisely, a “cognitive emotion” might be. If it is cognitive, it is a product or reason. If it is an emotion, it is not. And patterns that are “almost universal” means that they are not universal at all. Basing conclusion on patterns that are almost universal are, therefore, is dubious.

Despite all this, Herz brings to her reader’s attention a fact that most people – myself included – do not know. A sense of what is disgusting is unique to human beings. There are no other creatures in our world that have it.

I would like to think that the uniquely human sense of revulsion applies to things are not necessarily oozy, wriggly or putrid. Lapses in personal conduct should be assessed with the same intensity of revulsion. Certainly the Torah believes that they should, and thus applies the words “abomination” (to’eivah) and “lechery” (zimah) to a range of activities that are considered essentially abhorrent.   Further, the concept of “desecrating God’s name” is nothing other than an expression of profound revulsion towards an act that is fundamentally at odds with what is considered proper and expected.

My understanding of Judaism suggests that the beginning of moral confusion is related directly to a loss of the sense of revulsion.   The moment that we observe all kinds of crimes and sins with equanimity rather than disgust is the time our society is in peril.

Herz thus does us a service, whether her arguments are valid or not. She brings to our attention that fact there are valences to all things. And there are some things that are simply revolting.