Evolutionary psychology: Moral judgement based on "rather primitive emotion"

In "Psychologists Shed Light On Origins Of Morality" (ScienceDaily Mar. 2, 2009), we read,

In everyday language, people sometimes say that immoral behaviours “leave a bad taste in your mouth”. But this may be more than a metaphor according to new scientific evidence from the University of Toronto that shows a link between moral disgust and more primitive forms of disgust related to poison and disease.

“Morality is often pointed to as the pinnacle of human evolution and development,” says lead author Hanah Chapman, a graduate student in the Department of Psychology. "However, disgust is an ancient and rather primitive emotion which played a key evolutionary role in survival. Our research shows the involvement of disgust in morality, suggesting that moral judgment may depend as much on simple emotional processes as on complex thought."

See also: Neuroscience: Mirror neurons - cracks appearing?


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The U of T team found that people make similar facial movements in response to both primitive forms of disgust and moral disgust.

Ah, so that proves it then!

The problem with evolutionary psychology is not just its untethered speculation but its reflexive tendency to define explicitly human activities via non-human, subhuman, or prehuman models.

Moral disgust is an explicitly intellectual activity. Consider the following situations:

- a nursing home attendant flushes an old lady's dinner down the toilet so she doesn't have to help feed her, and steals from her purse when she is asleep. The old lady is too frightened to say anything.

- a social worker pressures clients to sleep with him, in which case he will put through the paperwork for benefits (to which they are legally entitled).

What provokes disgust is the difference between the way things are and the way they ought to be

So the question is, how do we know what ought to be?