The first chapter of Patricia S. Churchland's recent book, over at Princeton University Press:
So what is it to be fair? How do we know what to count as fair? Why do we regard trial by ordeal as wrong? Thus opens the door into the vast tangled forest of questions about right and wrong, good and evil, virtues and vices. For most of my adult life as a philosopher, I shied away from plunging unreservedly into these sorts of questions about morality. This was largely because I could not see a systematic way through that tangled forest, and because a lot of contemporary moral philosophy, though venerated in academic halls, was completely untethered to the “hard and fast”; that is, it had no strong connection to evolution or to the brain, and hence was in peril of floating on a sea of mere, albeit confident, opinion. And no doubt the medieval clerics were every bit as confident.
It did seem that likely Aristotle, Hume, and Darwin were right: we are social by nature. But what does that actually mean in terms of our brains and our genes? To make progress beyond the broad hunches about our nature, we need something solid to attach the claim to. Without relevant, real data from evolutionary biology, neuroscience, and genetics, I could not see how to tether ideas about “our nature” to the hard and fast.
Despite being flummoxed, I began to appreciate that recent developments in the biological sciences allow us to see through the tangle, to begin to discern pathways revealed by new data. The phenomenon of moral values, hitherto so puzzling, is now less so. Not entirely clear, just less puzzling. By drawing on converging new data from neuroscience, evolutionary biology, experimental psychology, and genetics, and given a philosophical framework consilient with those data, we can now meaningfully approach the question of where values come from.