A quick moral question. Imagine a runaway trolley headed for five people. All will certainly be killed unless you throw a switch that diverts the trolley onto another track, where it will kill one person. Should you throw the switch?
Another quick moral question. Imagine a runaway trolley headed for five people. The only way to stop the trolley requires that you push a large stranger onto the tracks, where he will die as his body stops the trolley. Should you push the stranger?1
How did you react to these two situations? If you were like me, then you accepted the first situation as okay, while the second one seemed irrational. However, take a second look. In the first situation, you save five people at the cost of one person. In the second situation, you save five people at the cost of one person. It's the exact same situation, and yet your reaction was different. Even though the logic is exactly the same. Why is this?
Jonathan Haidt's "social intuitionist" theory claims that moral feelings proceed moral feeling. Basically, he believes that during a moral decision, we first have a moral intuition (a gut level feeling), which we then create moral reasoning to explain. Therefore, most of our moral reasoning exists merely to defend our moral intuition. Dr. Joshua Greene at Princeton performed a study with the situation from above where he observed brain scans of people as they tried to answer the question. He found that the emotional center of the brain activated before they made any decision to act.
So much for the purely rational man. Emotions, no matter how we try to disassociate or label them away in our modern society, remain with us. Even during our most "rational" decisions. Better to know this truth and work with it than try to escape from our "primal" core.
1 This scenario comes from Psychology by David G. Meyers, and the case study was done by a Princeton team led by Joshua Greene.