> It's very rare that things are black or white, I can see it being all very grey
Yes, it's much easier to paint the whole world one color than trying to paint it in two colors: you'd have to make distinctions and that's quite hard. But on the other hand, if two colors are not enough to paint the whole world, surely one color is even less enough?
That might be an interesting experiment. Poll people on a large scale about dozens of minuscule moral issues that can be determined as GOOD or EVIL, then try to assemble more complex moral issues out of these building blocks. You could end up with some sort of statistical model of morality.
Yes, it's much easier to paint the whole world one color than trying to paint it in two colors: you'd have to make distinctions and that's quite hard. But on the other hand, if two colors are not enough to paint the whole world, surely one color is even less enough?