The Phenomenon of Moral Dumbfounding and Its Evolutionary Explanation

People often struggle to explain why they feel something is morally wrong. In the case of siblings having sex, some people may say it's wrong because it could lead to disabled offspring. However, if there is no chance of offspring, they still feel it's wrong. This is called moral dumbfounding. It might be explained by evolution - in our past, siblings having sex could result in abnormalities, so we developed an inhibition against it to ensure survival and healthy offspring.