I feel like the problem is that people hate contrived examples. "You have to choose whether to kill one person to save five." Well, I don't want that choice, so the first thing I'm going to do is look for alternatives that don't kill anybody. In the hypothetical that isn't allowed but in real life it is. A sufficiently clever person can in many cases figure out a way to save everybody, and either way the person who tries is justifiably more valued than the person who doesn't.<p>So what's wrong isn't choosing to save five people at the expense of one, it's the easy acceptance of killing anyone as a reasonable option.
It provides (or exhibits, or is indicative of [I'm not sure on any direction of causality]) maximum motivation for (especially collective) action.<p>I don't know about anyone else, but the more I see in shades of grey, the more I devolve into Hamlet-like indecision ("the best lack all conviction" is a self-flattering way to put it).
I don't think you have to bring evolution into it to explain why people like absolute moral rules. Take 'do not steal' vs maximise human happiness. Go with the latter and someone will nick your kit and claim it was for social good.
Disappointing to see such a supposedly august institution jumping on the current 'science communication' bandwagon of trumpeting minor psych results under clickbaity headlines. This is just trolling for REF impact points.
I'll admit I haven't and won't read the article. I would bother if it didn't really bother me. I'll reply to the essay in itself that is the title. Really, people favor black and white because of distrust. They don't trust others, or even themselves, with what they evaluate as slippery slopes. Maybe you need to differentiate. Maybe you can exercise good judgment and know when what. People, in practice, do this. They'll never hit a person who has good reason to be physically weak, unless the unthinkable and only reactable happens and that person starts aggressing their child. And boom, hard and fast describes the response, not the rules followed. And it doesn't count, and they don't feel guilty. But talking about this is difficult.<p>Also, look at it from the perspective of debt. The concept and many realities of debt permeate everything in modern life, especially morality. Black and white is really red and black: what I mean is that the concepts of evil and good :: heaven and hell :: serving and receiving interest are linked. Spending leads to debt / Serving yourself is evil: in death, you'll fall to hell, which is nothing other than payment for an unpayable debt that compounds faster than one can serve it. And heaven is not only the opposite, but the counterpart too: you have so many debtors paying you interest for all your good done or goods sold you are living off the interest.