Statesmen understand human nature. Why not psychologists and social scientists?

Most psychologists don’t like human nature, or at least not the idea of it. Clinicians, life coaches, and corporate motivators dislike it because it implies unchangeability. Anyone who took college psychology knows how to modify behavior, from direct instruction to manipulative advertising.

And then, what fool surveying the huge variety of human personalities, needs, and tastes would dream of trying to characterize all that as one thing? Well, some fool might, but not the philosophers, evolutionists, historians and political leaders who have long used the phrase. They’ve always meant something complex, varied, and big-but not limitless.

 Barack Obama, for instance. He talked about it in his Nobel Prize acceptance speech, a stark contrast to his famous speech in Cairo in the first spring of his presidency, when he reached out to the world. In Oslo he stepped up to accept the peace prize, and said, “[W]ar is sometimes necessary, and war is at some level an expression of human feelings.” He quoted John F. Kennedy, who said we should “‘focus on a more practical, more attainable peace, based not on a sudden revolution in human nature but on a gradual evolution in human institutions.'”

Leaders have long invoked human nature, and they don’t always accentuate the negative. Thomas Jefferson, in an early draft of the Declaration of Independence, denounced the British slave trade, saying the King “has waged cruel war against human nature itself , violating its most sacred rights of life and liberty in the persons of a distant people who never offended him.”

Ironic, of course, since Jefferson owned slaves, but a clear statement that slavery is contrary to human nature. In 1859, in his famous Cooper Union speech, Lincoln echoed the sentiment: “Human action can be modified to some extent, but human nature cannot be changed . There is a judgment and a feeling against slavery in this nation…” Four years later, amid a horrendous war, he signed the Emancipation Proclamation.

George Washington was no less a human nature theorist. As the Articles of Confederation stumbled, he wrote John Jay, the future Chief Justice, “We have probably had too good an opinion of human nature in forming our confederation,” and stressed the need for a “coercive” government power, which emerged in the Constitution.

But a hallmark of that second try was the separation and balance of powers, the direct result of the founders’ dim view of human nature . Power corrupts because human nature yields to temptation. Institutions must pit one corrupt group against another; power can only be checked by the countervailing power-lust of other humans.

In fact the Constitution was a kind of monograph on human nature, and at the same time one of the greatest of all inventions-a well-oiled, robust, intricate machine designed to keep the worst parts of human nature in check.

The founders were also influenced by the ideas of Benjamin Rush, the colonies’ leading physician and psychiatrist. He wrote of “the anatomy of mind,” and it included variation. In a model that Jefferson explicitly accepted, Whig and Tory-what we would now call liberal and conservative-were innate dispositions that could neither persuade each other nor be reconciled. Thus the machine of government had to allow them to grind at each other in controlled wars of words so they would not fall to civil wars of steel.

But again, it’s not just about the dark side. Here’s what Winston Churchill said at MIT a few years after the worst war in history:

“Scientists should never underrate the deep-seated qualities of human nature and how, repressed in one direction they will certainly break out in another. The genus homo if I may display my Latin – is a tough creature who has travelled here by a very long road. His nature has been shaped and his virtues ingrained by many millions of years of struggle, fear and pain, and his spirit has, from the earliest dawn of history, shown itself upon occasion capable of mounting to the sublime, far above material conditions or mortal terrors.”

Churchill invokes not just human nature but the “many millions of years” behind it. Obama the liberal and Churchill the conservative agree: Human nature has a dark side but also a spirit that can mount to the sublime. It embraces a broad but definable range of people, and there will always be a struggle not just among, but within each of us, as our ideal of the good contends with the selfish need to survive.

Without both, natural selection would long ago have consigned us to the trash heap of evolutionary history. This struggle, between our worst and best inclinations, is permanently part of us. Human nature is real, and it will not change soon.

For more on the founders’ ideas about human nature, see “Darwin’s Truth, Jefferson’s Vision.”

Note: By invitation, I’ve started a blog on the Psychology Today website , and my latest post can be read there or here, although different (and likely more numerous) comments will be  posted there.