Steven Pinker
The Blank Slate
The genes have metaphorical motives—making copies of themselves—and the organisms they design have real motives. But they are not the same motives. Sometimes the most selfish thing a gene can do is wire unselfish motives into a human brain—heartfelt, unstinting, deep-in-the-marrow unselfishness. The love of children (who carry one's genes into posterity), a faithful spouse (whose genetic fate is identical to one's own), and friends and allies (who trust you if you're trustworthy) can be bottomless and unimpeachable as far as we humans are concerned (proximate level), even if it is metaphorically self-serving as far as the genes are concerned (ultimate level).
I suspect there is another reason why the explanations are so easily confused. We all know that people sometimes have ulterior motives. They may be publicly generous but privately greedy, publicly pious but privately cynical, publicly platonic but privately lusting. Freud accustomed us to the idea that ulterior motives are pervasive in behavior, exerting their effects from an inaccessible stratum of the mind. Combine this with the common misconception that the genes are a kind of essence or core of the person, and you get a mongrel of Dawkins and Freud: the idea that the metaphorical motives of the genes are the deep, unconscious, ulterior motives of the person. That is an error. Brooklyn is not expanding.
Even people who can keep genes and people apart in their minds might find themselves depressed. Psychology has taught us that aspects of our experience may be figments, artifacts of how information is processed in the brain. The difference in kind between our experience of red and our experience of green does not mirror any difference in kind in lightwaves in the world—the wavelengths of light, which give rise to our perception of hue, form a smooth continuum. Red and green, perceived as qualitatively different properties, are constructs of the chemistry and circuitry of our nervous system. They could be absent in an organism with different photopigments or wiring; indeed, people with the most common form of colorblindness are just such organisms. And the emotional coloring of an object is as much a figment as its physical coloring. The sweetness of milk, the scariness of heights, and the vileness of carrion are fancies of a nervous system that evolved to react to those objects in adaptive ways.
The sciences of human nature seem to imply that the same is true of right and wrong, merit and worthlessness, beauty and ugliness, holiness and baseness. They are neural constructs, movies we project onto the interior of our skulls, ways to tickle the pleasure centers of the brain, with no more reality than the difference between red and green. When Marley's ghost asked Scrooge why he doubted his senses, he said, 'Because a little thing affects them. A slight disorder of the stomach makes them cheats. You may be an undigested bit of beef, a blot of mustard, a crumb of cheese, a fragment of an underdone potato. There's more of gravy than of grave about you, whatever you are!' Science seems to be saying that the same is true of everything we value.
But just because our brains are prepared to think in certain ways, it does not follow that the objects of those thoughts are fictitious. Many of our faculties evolved to mesh with real entities in the world. Our perception of depth is the product of complicated circuitry in the brain, circuitry that is absent from other species. But that does not mean that there aren't real trees and cliffs out there, or that the world is as flat as a pancake. And so it may be with more abstract entities. Humans, like many animals, appear to have an innate sense of number, which can be explained by the advantages of reasoning about numerosity during our evolutionary history. (For example, if three bears go into a cave and two come out, is it safe to enter?) But the mere fact that a number faculty evolved does not mean that numbers are hallucinations. According to the Platonist conception of number favored by many mathematicians and philosophers, entities such as numbers and shapes have an existence independent of minds. The number three is not invented out of whole cloth; it has real properties that can be discovered and explored. No rational creature equipped with circuitry to understand the concept 'two' and the concept of addition could discover that two plus one equals anything other than three. That is why we expect similar bodies of mathematical results to emerge from different cultures or even different planets. If so, the number sense evolved to grasp abstract truths in the world that exist independently of the minds that grasp them.
Perhaps the same argument can be made for morality. According to the theory of moral realism, right and wrong exist, and have an inherent logic that licenses some moral arguments and not others. The world presents us with non-zero-sum games in which it is better for both parties to act unselfishly than for both to act selfishly (better not to shove and not to be shoved than to shove and be shoved). Given the goal of being better off, certain conditions follow necessarily. No creature equipped with circuitry to understand that it is immoral for you to hurt me could discover anything but that it is immoral for me to hurt you. As with numbers and the number sense, we would expect moral systems to evolve toward similar conclusions in different cultures or even different planets. And in fact the Golden Rule has been rediscovered many times: by the authors of Leviticus and the Mahabharata; by Hillel, Jesus, and Confucius; by the Stoic philosophers of the Roman Empire; by social contract theorists such as Hobbes, Rousseau, and Locke; and by moral philosophers such as Kant in his categorical imperative. Our moral sense may have evolved to mesh with an intrinsic logic of ethics rather than concocting it in our heads out of nothing.
But even if the Platonic existence of moral logic is too rich for your blood, you can still see morality as something more than a social convention or religious dogma. Whatever its ontological status may be, a moral sense is part of the standard equipment of the human mind. It's the only mind we've got, and we have no choice but to take its intuitions seriously. If we are so constituted that we cannot help but think in moral terms (at least some of the time and toward some people), then morality is as real for us as if it were decreed by the Almighty or written into the cosmos. And so it is with other human values like love, truth, and beauty. Could we ever know whether they are really 'out there' or whether we just think they are out there because the human brain makes it impossible not to think they are out there? And how bad would it be if they were inherent to the human way of thinking? Perhaps we should reflect on our condition as Kant did in his Critique of Practical Reason: 'Two things fill the mind with ever new and increasing admiration and awe, the oftener and more steadily we reflect, on them: the starry heavens above and the moral law within.'