There is a piece of wisdom, an ‘is’ can not make an ‘ought’. But also the opposite is true, an ‘ought’ can not make an ‘is’. Just because we feel we ought to have a rational moral sense, does not mean we do have. Just because utilitarianism (least total harm/greatest total benefit) is considered by many to be the right way to make moral decisions, does not mean that is how we have evolved. We do not even have much evidence that our morality is a unified system that could be described in a few principles. In fact, it is doubtful, in an evolutionary sense, that our moral sense has the function of making us good. It is much easier to envisage it as having the function of protecting the integrity of social groups.
I once brought some criticism down on my head from many different directions, not just utilitarians, by giving the option that morality was trying to avoid guilt and shame especially, but also regret. Of course this is way to simplistic but it has a grain of truth about it morality is about emotion and not cognition. The person who says that they would murder one person to save five, very probably could not do it in the few seconds they had to do the murder. They would be emotionally incapable of the action unless they had been prepared for it over some time.
Bartels and Pizarro (see citation) have looked at who endorses utilitarian decisions to moral questions. Of course this does not mean that in real life they would actually do similar things, but some might. What they found was that the type of person that choose the utilitarian option in stark but improbable scenarios, was the type of person that in ordinary circumstances we would regard as lacking morality. Here is their abstract:
Researchers have recently argued that utilitarianism is the appropriate framework by which to evaluate moral judgment, and that individuals who endorse non-utilitarian solutions to moral dilemmas (involving active vs. passive harm) are committing an error. We report a study in which participants responded to a battery of personality assessments and a set of dilemmas that pit utilitarian and non-utilitarian options against each other. Participants who indicated greater endorsement of utilitarian solutions had higher scores on measures of Psychopathy, machiavellianism, and life meaninglessness. These results question the widely-used methods by which lay moral judgments are evaluated, as these approaches lead to the counterintuitive conclusion that those individuals who are least prone to moral errors also possess a set of psychological characteristics that many would consider prototypically immoral.
The bottom line I think is that groups and most individuals in groups, people who rely on one another, are under the thumb of some powerful emotional forces that are protective of the group and so also of most individuals in the group. We distrust those that are emotionally callous and manipulative because we cannot rely on their emotional responses. We do not want to live with people who will commit murder because it happen to be logical to them and do not feel an emotional brake on their actions.
One implication of adopting a utilitarian framework as a normative standard in the psychological study of morality is the inevitable conclusion that the vast majority of people are often morally wrong. For instance, when presented with Thomsons footbridge dilemma, as many as 90% of people reject the utilitarian response .
In the end morality is not about least harm or most good or rules or logic, it is about maintaining societies that are stable, safe and livable. Maybe morality ‘ought’ to be unemotional and that does not mean it ‘is’. I do not think it even ought to be unemotional.
Bartels, D., & Pizarro, D. (2011). The mismeasure of morals: Antisocial personality traits predict utilitarian responses to moral dilemmas Cognition, 121 (1), 154-161 DOI: 10.1016/j.cognition.2011.05.010