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人間の本性はどこまで個人主義なのか?

人間の本性はどこまで個人主義なのか?

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September 8, 2010

Winter 2005 -- “You’re right to point out the contrast I make between capitalism and morality.” So said New York Times columnist John Tierney in response to my 2002 article about his ongoing efforts to defend free markets. I had called my piece “Two Cheers for John Tierney,” because, after praising the libertarian columnist, I took him to task for the ethical sentiment embodied in one of his headlines: “Good? No, But Greed Is Useful.” “That expresses Tierney’s view perfectly,” I wrote. “Benevolence, generosity, the holiday season, kindness to strangers, and acts not motivated by self-interest are good. Greed is not good, but it works.”Shortly afterward, Tierney wrote to me, pointing out that he does not compose his own headlines, but admitting his ambiguous attitude toward self-interest. Citing science writer Matt Ridley as his authority, Tierney maintained: “We evolved in clans with an apparently innate sense that goodness equates with altruism—it’s a belief common in every culture. . . . Beyond the clan, we need to rely on selfishness to produce the best moral outcome. So in that sense, selfishness is good, but we instinctively recoil at that thought.”

Is it true, as Tierney suggested, that mankind’s resistance to ethical individualism is innate or instinctive? Recently, I decided to examine the book Tierney recommended—Ridley’s The Origins of Virtue: Human Instincts and the Evolution of Cooperation—to see if its arguments for man’s predisposition to altruism were as convincing to me as to him.

THE FRAMEWORK

Ridley’s book draws heavily from the methods of evolutionary psychology, a relatively recent theory that interprets basic human behaviors and attitudes in light of certain assumptions about man’s evolutionary background. According to this theory, our brain—like the rest of our body—was shaped by natural selection during eons of biological evolution, tens of millions of years of primate evolution, and 2.5 million years of human evolution. Over that time, the brain slowly improved its ability to process information and initiate behavior in ways that led to successful survival and procreation. But the abilities that evolved were abilities to foster successful lives and procreation under the circumstances that prevailed in the Stone Age. The human brain has not had nearly enough time to adapt to modern conditions. The result is summarized by evolutionary psychologists Leda Cosmides and John Toobyin “Evolutionary Psychology: A Primer”: “ Our modern skulls house a Stone Age mind”.

But why should that matter? Successful lives in the Stone Age, like successful lives today, surely required action rationally based on problem-solving. In any age, it would seem, a successful person gathers evidence, sifts it, forms hypotheses, tests them, draws conclusions, and adapts his behavior to the realities he thus comes to know.

Evolutionary psychologists dissent from that view in two major ways. First, on the basis of certain experiments, they reject the idea that the human mind works with generalized logical methods: “gathering evidence as such” or “testing hypotheses as such.” Instead, they claim to have shown that evolution has produced human minds with myriad structures for solving highly concrete problems. Secondly, they dissent from the idea that most problem-solving is carried out consciously. Rather, they hold, much of our thinking goes on subconsciously, with conclusions generally appearing in the conscious mind only after they have been formed.

Thus, evolutionary psychologists might observe that most people do not know how to employ the scientific method, with its rules for accumulating data and drawing conclusions. Yet a person’s subconscious seems able, with amazing accuracy, to accumulate data and reach conclusions about the faithfulness of his or her spouse. Why should this be? Evolutionary psychologists might explain the fact by pointing out that natural selection would highly favor such an ability, because Stone Age man needed urgently to know if his spouse was violating the pair-bond that lies at the heart of human society.

In his book, Ridley employs the methods of evolutionary psychology to solve the two mysteries mentioned in his title—the evolution of cooperation and the origins of virtue. Natural selection, he maintains, favored instincts that promoted the human individual’s survival and procreation. To that extent, human nature is individualist. But two puzzles must be solved in light of that individualist premise: How did a process promoting individual survival and procreation bring about the human instinct for cooperation with strangers? And: How did such a process bring about the human instinct for preaching—and occasionally practicing—a morality of self-sacrifice?  

ALTRUISM AS VIRTUE

Ridley begins his argument by asserting that all cultures hold altruism to be the human moral standard.

    Selfishness is almost the definition of vice. . . . Virtue is, almost by definition, the greater good of the group. . . . The conspicuously virtuous things we all praise—cooperation, altruism, generosity, sympathy, kindness, selflessness—are all unambiguously concerned with the welfare of others. This is not some parochial Western tradition. It is a bias shared by the whole species. . . . Consciously or implicitly, we all share a belief in pursuing the greater good. We praise selflessness and decry selfishness (p. 38).

Here, then, is the key puzzle. If natural selection has so constructed human nature that men act in their own self-interest (or occasionally in the interest of their propagation), why has natural selection also led men to establish a moral standard contradicting human nature? Ridley cites naturalist George Williams as stating the paradox: “‘How could maximizing selfishness [via natural selection] produce an organism capable of often advocating, and occasionally practicing, charity towards strangers and even towards animals?’” (p. 38).

THE INVISIBLE HAND

As part of his search for the evolutionary source of altruistic attitudes, Ridley examines the proclivity of primitive men to exchange favors with strangers. Is such exchange a form of altruism? Ridley rejects that conclusion, invoking Adam Smith’s famous analysis of trade:

    Man has almost constant occasion for the help of his brethren, and it is in vain for him to expect it from their benevolence only. He will be more likely to prevail if he can interest their self-love in his favour, and show them that it is for their own advantage to do for him what he requires of them. . . . It is not from the benevolence of the butcher, the brewer, or the baker that we expect our dinner, but from their regard to their own interest.

Still, cash-on-the-barrel-head trade is not the whole of human interaction, not even of human interaction outside families. Humans also give gifts. They are generous. Does generosity contain the seeds of altruistic morality?

GENEROSITY AS SELF-INTEREST

Ridley examines the universal practice of food-sharing, particularly meat-sharing, and asks what purposes primitive men might have for sharing food with their group. He finds two explanations current in anthropological circles. The first is that sharing meat is a straightforward attempt to reduce the risk of meat shortages: The hunter shares meat with “his friends from whom he had had, or expects to have, a reciprocal favour. This evens out his supply of meat by giving him to expect a share of others’ carcasses in the future” (p. 114).

That, however, cannot be the whole explanation, Ridley notes, because incompetent and idle men, from whom future meat cannot be expected, are also allowed to share. The fuller explanation must be that meat-sharing reduces risk because the sharer’s generosity gains him prestige and he can later trade that prestige for meat or sex or some other good he lacks. In that way, meat-sharing welds primitive individuals into a group that looks forward to future exchanges of many and diverse kinds. It creates a standing group of potential traders, which Ridley rightly calls “the very basis of society” (p. 88).

Yet all of this generosity can be explained in terms of self-interested trade, if one looks at it in a broad enough context. So, although Ridley may be closing in on his search for “the evolution of cooperation,” he seems no closer to locating the origins of virtue, understood as altruism.

GENEROSITY AS CHARITY

What about the sort of generosity exemplified by charitable donations to impersonal institutions or unknown individuals? Ridley’s examples are giving blood and working in Rwanda. Are such deeds altruistic? Or can they, too, be motivated by self-interest?

Well, what might be the self-interested reasons for engaging in such generosity? Perhaps it is just that altruists take pleasure in being generous. Ridley admits that they do. Yet that is not a satisfactory answer to an evolutionary psychologist. Why would natural selection produce humans who took pleasure in giving away values (goods or time) that they could better employ to foster and insure their survival or self-propagation? It seems not to make sense. And so Ridley comes back to the paradox stated by George Williams: How could natural selection, a process that maximizes selfishness, produce a charitable species? What is the evolutionary origin of altruism?

Ridley has an answer: If we are going to reap the gains of cooperation through trade, he argues, we must demonstrate to potential partners that we will not “take the money and run,” even if we have an opportunity to profit by doing so. The point of adhering to moral principles (such as generosity and honesty) is that it lets us prove we will “do the right thing,” even if we suffer concrete losses by it. If individuals did not have a way to demonstrate such moral character, Ridley believes, “rational people would be unable to convince each other of their commitment and would never close the deals” (p. 135).

But doesn’t this analysis again slip self-interest in through the back door? As Ridley puts it: “A cynic might reasonably reply that the reputation for trustworthiness that honesty earns is itself just reward amply balancing the costs of occasional altruism. . . . Therefore, far from being truly altruistic, the cooperative person is merely looking to his long-term self-interest, rather than the short term” (p. 137).

According to Ridley, however, this pursuit of long-range interest through generosity is altruistic and not selfish, because a person wishing to signal that he is trustworthy and not calculative must perform virtuous acts because of “moral sentiments,” not calculation. Natural selection makes service to others an integral part of pursuing our long-range interest—but it demands that pursuing our long-range interest not be the motive of such service to others.

In the end, then, Ridley says: Human nature is individualist through and through—if one looks only at acts and their consequences. At the same time, however, humans have a deep-seated inclination to urge (and occasionally to perform) acts motivated by self-sacrifice, in order to reap the benefits of trade by demonstrating their non-calculative attitudes and thus their trustworthiness.

AN EVOLVING ARGUMENT

What shall we say of this? Was John Tierney correct when he wrote that “selfishness is good but we instinctively recoil at that thought”? Is the Stone Age mind that we carry in our modern skulls thoroughly selfish yet ineradicably endowed with altruist sentiments? Even if we grant Ridley all his game-theory notions, animal-behavior reports, and anthropological studies, I think he has not proven his case. Two major flaws undercut his argument.

First, the whole framework of evolutionary psychology is questionable. I am not competent to judge the discipline’s details, but anyone can see that it tries to explain human nature and social behavior while denying free will. In “Evolutionary Psychology: A Primer,” Cosmides and Tooby say flatly: “The brain is a physical system whose operation is governed solely by the laws of chemistry and physics. What does this mean? It means that all your thoughts and hopes and dreams and feelings are produced by chemical reactions going on in your head.” And Ridley ridicules those who believe that “we are conscious, rational, and free-willed, not like those inferior things called animals.” The problem is that, in fact, we have all those characteristics he mocks, and Ridley’s failure to take account of reason and volition fatally weakens the lessons he draws from animal behavior and primitive culture.

Secondly, The Origins of Virtue uses ethical terms in a very confused way. For example, when discussing short-range self-interest and long-range self-interest, Ridley writes: “Amartya Sen has called the caricature of the short-sighted self-interested person a ‘rational fool.’ If the rational fool turns out to be taking short-sighted decisions then he is not being rational just short-sighted” (p. 137). Obviously, that truth is central to any argument about self-interest and altruism. Yet immediately after this passage, Ridley writes: “such quibbling aside.” His all-too-frequent equation of short-term gain with rational self-interest muddies his discussions of selfishness and altruism.

Nevertheless, Ridley’s case studies of animal behavior and primitive culture do raise provocative questions for those of us who look to organisms, human and subhuman, in order to understand life and death, self and others, personal existence and personal identity, values and virtues, actions and emotions. If Ridley has not found the basis of human morality, he has at any rate provided additional tools for its discovery. If he has not demonstrated the roots of men’s hostility to individualism, he has demonstrated that philosophical and psychological explanations of such hostility need to rest on a foundation of biology and anthropology.

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