STEVEN PINKER: I don't consider myself to be that radical a thinker. My opinions about human nature are shared by many psychologists, linguists, and biologists, not to mention philosophers and scholars going back centuries. The connections I draw between human nature and political systems in my new book, for example, were prefigured in the debates during the Enlightenment and during the framing of the American Constitution. Madison, for example, asked "What is government itself but the greatest of all reflections on human nature?" People today sometimes get uncomfortable with empirical claims that seem to clash with their political assumptions, often because they haven't given much thought to the connections. But a conception of human nature, and its connections to other fields such as politics and the arts, have been there from time immemorial.

EDGE: What questions are you asking yourself, and what do you hope to accomplish by going after the intellectual establishment in terms of their denial of human nature?

PINKER: The main question is: "Why are empirical questions about how the mind works so weighted down with political and moral and emotional baggage? Why do people believe that there are dangerous implications of the idea that the mind is a product of the brain, that the brain is organized in part by the genome, and that the genome was shaped by natural selection?" This idea has been met with demonstrations, denunciations, picketings, and comparisons to Nazism, both from the right and from the left. And these reactions affect both the day-to-day conduct of science and the public appreciation of the science. By exploring the political and moral colorings of discoveries about what makes us tick, we can have a more honest science and a less fearful intellectual milieu.

EDGE: Why do we need to assuage people's fears? What's the matter with telling the truth?

PINKER: It's harder to find the truth if certain factual hypotheses are third rails—touch them and die. A clear example is research on parenting. Hundreds of studies have measured correlations between the practices of parents and the way their children turn out. For example, parents who talk a lot to their children have kids with better language skills, parents who spank have children who grow up to be violent, parents who are neither too authoritarian or too lenient have children who are well-adjusted, and so on. Most of the parenting expert industry and a lot of government policy turn these correlations into advice to parents, and blame the parents when children don't turn out as they would have liked. But correlation does not imply causation. Parents provide their children with genes as well as an environment, so the fact that talkative parents have kids with good language skills could simply mean that and that the same genes that make parents talkative make children articulate. Until those studies are replicated with adopted children, who don't get their genes from the people who bring them up, we don't know whether the correlations reflect the effects of parenting, the effects of shared genes, or some mixture. But in most cases even the possibility that the correlations reflect shared genes is taboo. In developmental psychology it's considered impolite even to mention it, let alone test it.

EDGE: Why?

PINKER: Most intellectuals today have a phobia of any explanation of the mind that invokes genetics. They're afraid of four things.

First there is a fear of inequality. The great appeal of the doctrine that the mind is a blank slate is the simple mathematical fact that zero equals zero. If we all start out blank, then no one can have more stuff written on his slate than anyone else. Whereas if we come into the world endowed with a rich set of mental faculties, they could work differently, or better or worse, in some people than in others. The fear is that this would open the door to discrimination, oppression, or eugenics, or even slavery and genocide.

Of course this is all a non sequitur. As many political writers have pointed out, commitment to political equality is not an empirical claim that people are clones. It's a moral claim that in certain spheres we judge people as individuals, and don't take into account the statistical average of the groups that they belong to. It's also a recognition that however much people might vary, they have certain things in common by virtue of their common human nature. No one likes to be humiliated or oppressed or enslaves or deprived. Political equality consists of recognizing, as the Constitution says, that people have certain inalienable rights, namely life, liberty, and the pursuit of happiness. Recognizing those rights is not the same thing as believing that people are indistinguishable in every respect.

The second fear is the fear of imperfectability. If people are innately saddled with certain sins and flaws, like selfishness, prejudice, sort-sightedness, and self-deception, then political reform would seem to be a waste of time. Why try to make the world a better place if people are rotten to the core and will just screw it up no matter what you do? Again, this is a faulty argument. We know that there can be social improvement because we know that there has been social improvement, such as the end of slavery, torture, blood feuds, despotism, and the ownership of women in Western democracies. Social change can take place, even with a fixed human nature, because the mind is a complex system of many parts. Even if we do have some motives that tempt us to do awful things, we have other motives that can counteract them. We can figure out ways to pit one human desire against another, and thereby improve our condition, in the same way we manipulate physical and biological laws—rather than denying they exist—to improve our physical condition. We combat disease, we keep out the weather, we grow more crops, and we can jigger with our social arrangements as well.

A good example is the invention of democratic government. As Madison argued, by instituting checks and balances in a political system, one person's ambition counteracts another's. It's not that we have bred or socialized a new human being who's free of ambition. We've just developed a system in which these ambitions are kept under control.