Michael Egnor's ‘Waiter, My Steak Isn’t Altruistic Enough!’ discusses attempts by neuroscientists to account for altruism. From the article (in green).
The mainstream view among neuroscientists is that the mind, and such things as morality and altruism, are ‘emergent’ properties of the brain, caused entirely by neurons and chemistry. They believe that the brain is a sufficient cause for the mind, and they see human morality as a trait crafted by evolution. I think this view is wrong.
For one process to cause another there must be a point of contact, in the sense that the processes linked in cause and effect must share properties in common. In biology, the liver contains molecules of enzymes and bilirubin and cholesterol, which cause the secretion of molecules of bile. In physics, a moving billiard ball collides with another billiard ball, causing each to change course. Each billiard ball starts with momentum, and momentum is exchanged when they collide. The transfer of momentum mediates the cause and effect. “Cause and effect’ presupposes commonality of at least one property- enzymes or bilirubin or cholesterol or momentum. Without commonality, there is no link through which cause can give rise to effect.
Egnor makes a good point. Is morality and altruism explained by neurons and biochemistry alone? How does the notion that morality and altruism are manifestations of an "emergent property" of the brain indicate cause and effect linkage? What is the shared property? The phrase "emergent property" is a common one but its descriptive value does not enable us to pin down exactly what is the common link between thought and emotions on the one hand and brain matter on the other. We are able to associate biochemicals and reactions among them with brain activity but the predictive utility of such associations is far from a scientifically comprehensive level. Personality profiles give us a much better predictive yardstick than an individual's unique biochemical make-up.
The nature of thought and brain cells differ to such an extent that detailed causality models of altruism are more a dream than reality. Explanations of altruisitc behavoir have an ad hoc appearance. Selfishness reigning over altruism easily lends itself to a survival or pleasure enhancement interpretation but when the reverse occurs then what? A different kind of pleasure that comes with doing good? Group instinct dynamics? Explanations seem more driven by theory than particulars unique to a given situation.