The Enlightenment is often called the Age of Reason. Thinkers sought to remove the cloak of custom to understand the laws of the natural and human worlds supposedly underneath. As Tom Paine wrote in Common Sense, "A long habit of not thinking a thing wrong, gives it a superficial appearance of being right, and raises at first a formidable outcry in defense of custom." Reason, however, could see through custom to discover what Thomas Jefferson referred to as "self-evident" truths, none more so than natural rights. But what made these rights self-evident, asks Lynn Hunt in her important book Inventing Human Rights.

The American and French revolutions boldly asserted that all men are created equal, profoundly challenging custom. "How did these men, living in societies built on slavery, subordination, and seemingly natural subservience, ever come to imagine men not at all like them and, in some cases, women too, as equals? How did equality of rights become a 'self-evident' truth in such unlikely places? It is astounding that men such as Jefferson, a slave owner, and Lafayette, an aristocrat, could speak as they did of the self-evident, inalienable rights of all men," Hunt writes.

Self-evident truths about human equality did not emerge just because Paine, Jefferson and others reasoned their way back to nature; they also corresponded with eighteenth-century Europeans' emotional responses to human suffering. Claims for self-evidence rested on an "inner emotional reference point," Hunt argues. She seeks to tell us when and how this emotional reference point emerged and why it supported human rights.

Kings and nobles had once assumed that the world was naturally divided into distinct orders. Sometime in middle 18th century, however, elites came to believe that people in vastly different social realms were more alike than different because they feel pain and joy in the same way. When we see a person's suffering, Adam Smith wrote, "We enter as it were into his body and become in some measure him." This process-- what we now call empathy-- opened elites' eyes to the common elements of human nature, making it possible to talk about what unites rather than divides human beings from each other.

Why did we start to empathize in new ways in the 18th century? The most important factor was the experience of reading novels or accounts of torture that invited readers to identify with suffering characters. The epistolary style of Samuel Richardson's Pamela (1740) and Clarissa (1747-48) and Jean-Jacques Rousseau's Julie (1761), for example, enable readers to experience the main character's anguish directly. Despite the social space that might have separated an elite reader from Pamela, readers felt her pain.

Based on recent work in neuroscience, Hunt adds that the experience of empathizing with a character literally transformed the minds of readers. "Reading accounts of torture or epistolary novels had physical effects that translated into brain changes and came back out as new concepts about the organization of social and political life." The experience of identifying with Pamela's suffering was so intense that it re-oriented people's minds in ways that enabled them to assume that every human body experiences pain. Once our minds can empathize it becomes difficult to look away when we see human suffering.

Richardson's and Rousseau's readers had intensely "visceral" reactions. After finishing Clarissa, the poet Thomas Edwards wrote, "I never felt so much distress in my life as I have done for that dear girl." A reader of Julie told Rousseau, "You have driven me crazy about her. Imagine then the tears that her death must have wrung from me... Never have I wept such delicious tears. That reading created such a powerful effect on me that I believe I would have gladly died during that supreme moment." Such intense reactions demonstrate readers' emotional transformation as they, perhaps for the first time, empathized with a stranger from a different social sphere.

Once readers learned to see in strangers a common ability to feel pain and joy, the age-old practice of torture quickly came under attack. In 1762 a debate broke out after a Toulouse court convicted Protestant Jean Calas of murdering his son to prevent his conversion to Catholicism. Calas was sentenced to death by breaking on the wheel. First he was subjected to the "preliminary question," judge-overseen torture to get Calas to reveal any accomplices. Wrists tied tightly to a bar behind him and his legs held down by a weight, Calas's arms were stretched by cranks and pulleys. When Calas did not confess, pitchers of water were forced down his throat. Finally he was placed on the wheel.

Breaking on the wheel has two steps. The executioner first ties the body to a cross and then crushes the condemned's forearms, legs, thighs, and arms. A wince dislocates the vertebrae. The broken body is then attached to the wheel and left in anguish.

The Calas affair galvanized French public opinion. Voltaire, among others, argued that torture violates human nature. Before it could do so, Hunt argues, people had to learn to internalize the suffering of Calas, a man unknown to them. By the latter half of the eighteenth century, empathy convinced penal reformers in the Atlantic world that torture was barbarous. As Benjamin Rush noted in 1787, criminals "possess souls and bodies composed of the same materials as those of our friends and relations. They are bone of their bone."

It was in the context of these new emotional responses that the Declaration of Independence (1776) and the Declaration of the Rights of Man and Citizen (1789) were published. Once men like Jefferson and Lafayette, or Voltaire and Rush, concluded that other bodies respond to pain much like theirs would, it followed that rights were vital to protect the dignity of all persons. Empathy, Hunt concludes, was the precondition to making these documents plausible to their writers and readers.

If the European world underwent an emotional transformation in the eighteenth century, why have human rights been consistently violated in the years since? Hunt has two answers. First, during the nineteenth century the locus of rights shifted from nature to the nation-state. Second, and more disturbing, she concludes that the emotional transformation she traces produced its antithesis-- an ability to experience erotic pleasure from suffering, embodied in the Gothic novel. Like empathy, gothicism asks us to imagine ourselves in the position of others in pain. Before we can take pleasure in others' pain, however, we must first learn to empathize with them.

Hunt's emphasis on empathy over reason as the basis of human rights might trouble those who wish to found rights on transcendent principles, whether rational or divine. Yet Hunt never claims that human rights lack such justification, but that their vitality depends on our emotions. In Hunt's words, "Human rights are not just a doctrine formulated in documents; they rest on a disposition toward other people."

Hunt reminds us that reason alone cannot sustain human rights. This is what is really at stake in the current debate over whether Americans sanction torture as part of the Global War on Terror. We talk of law and its limits but ignore the real issue: how would we feel if we were America's prisoners? If we stop empathizing with the bodies of suspected or actual terrorists, we act as if their bodies are different than our own, dehumanize them, and thus open the door to relativism by making humans less, not more, alike.