In October 1997, Judge Richard Posner gave the prestigious Oliver Wendell Holmes lectures at Harvard Law School. He used the occasion to launch a bruising attack on the members of his audience and their pretensions to virtue. "Academic moralists," he tartly proclaimed, "pick from an à la carte menu the moral principles that coincide with the preferences of their social set." With considerable aplomb, he proceeded to accuse the nation's leading moral and legal philosophers of hypocrisy and worse: "They have the intellectual agility to weave an inconsistent heap of policies into a superficially coherent unity and the psychological agility to honor their chosen principles only to the extent compatible with their personal happiness and professional advancement."

Slighted and vexed, several scholars from the ranks of moral philosophy, legal scholarship, and the judiciary responded to Posner in a subsequent issue of the Harvard Law Review. The liberal legal philosopher Ronald Dworkin charged that Posner's talk contributed to "a populist antitheoretical movement that is now powerful in American intellectual life." The University of Chicago philosopher and classicist Martha Nussbaum called it "an occasion for sadness." Charles Fried, an associate justice of the Supreme Judicial Court of Massachusetts and solicitor general under former president Ronald Reagan, said that Posner's harangue was "too gross and unnuanced to dispose of the arguments he seeks to refute," though with his rhetorical skills he presumably "made converts."

Provocation comes naturally to Posner. Like his hero Oliver Wendell Holmes, whom he has called the "American Nietzsche," Posner has sought to combine the roles of intellectual gadfly and authoritative lawgiver. The object of scholarly envy and awe, he is the chief judge of the United States Court of Appeals for the Seventh Circuit and was the court-appointed mediator for the Microsoft antitrust case. Anthony Kronman, the dean of the Yale Law School, considers the "law and economics" movement that Posner has pioneered to be the most influential development in the last two decades of legal scholarship. The author of thirty books and more than fifteen hundred judicial opinions (which he writes himself), he is the most frequently cited American legal scholar alive.

And yet for all his visibility and near superhuman productivity, Posner is maddeningly hard to pin down. At sixty-one, he is quiet, calm, and courteous, with a measured style of speech; he expresses his often incendiary opinions in an unhurried, almost blasé manner. The best description of his political views may be "eclectic libertarian," but even that label doesn't capture the quirky cast of his thought. On his conservative side, he is a Reagan-appointed judge who warns against market regulation and wealth redistribution. He professes distaste for the student riots and antiwar demonstrations of the 1960s, which he characterizes as an "anarchic outburst." He puts a good deal of stock in current theories of evolutionary psychology and sociobiology, believes that the exclusion of women by the Virginia Military Institute was not plausibly an instance of "sex subordination," and agrees with Supreme Court justice Antonin Scalia that "people who look to the courts for social reform do not take democracy completely seriously."

That said, Posner seems to make a point of infuriating conservatives. In a December 1999 New York Times Book Review article, he roundly criticized neoconservative Gertrude Himmelfarb's jeremiad One Nation, Two Cultures, warning that "unless we want to go the way of Iran, we shall not be able to return to the era of premarital chastity, low divorce, stay-at-home moms, pornography-free media and the closeting of homosexuals and adulterers." As a self-styled pragmatist, he most closely resembles, in his philosophical views, such b&#ecirc;tes noires of the right wing as Stanley Fish and Richard Rorty. In the fall 1999 Raritan, he casually dismissed the hallowed notion of "the rule of law" by noting that it is "an accidental and readily dispensable element of our legal ideology." His books are enthusiastically blurbed by liberals, he is the highest-ranking American judge to have publicly advocated the legalization of marijuana, and he resists nostalgic views of a more stately, less rapacious American legal profession, claiming that "the bar in the 1950s was a regulated cartel."

Posner's work may be elusive in its implications and almost absurdly wide ranging in subject matter, but it is also largely unified in method. Since 1988, he has written books on sex, old age, literature, and AIDS. Yet for all his enlightened dilettantism, the discipline of economics, as he put it in Aging and Old Age (1995), "wields the baton of my multidisciplinary orchestra." He believes firmly in the ability of rational choice theory — the economic model of appetitive, self-interested human behavior — to dispel the myths that cloud other disciplines. In Sex and Reason (1992), for instance, he described prostitution as a "substitute for marriage," since married couples compensate each other for services with other services, while prostitution is simply a case of those same services being traded for ready money. Typically erudite, syncretic, and hard-nosed, Aging and Old Age was inspired by a quotation from Aristotle's Rhetoric — "youth has a long future before it and a short past behind it" — in which Posner saw the glimmer of cost-benefit calculation.

To his admirers, this is classic Posner: the impossibly well-read, mind-bogglingly prolific Renaissance judge; the forthright, courageous, and accurate critic of all that is soft and imaginary in legal and social thought; and the economic wizard who captures the complexity of human beings by teasing out their crude self-interests. To his detractors, however, Posner's work reveals considerably less: a gifted but wayward mind, given to reductive, simple minded analysis of the variegated human experience, seduced by a cynical narrative of power and survival; a dogmatic, heartless, calculating machine in pursuit of cold-blooded efficiency; a "fetishist," as Dworkin once put it, "of little green paper."

To the delight of his fans and the dismay of his critics, Posner published two especially controversial books last year: The Problematics of Moral and Legal , an expanded version of his 1997 Holmes lectures; and An Affair of State: The Investigation, Impeachment, and Trial of President Clinton. Both advance audacious arguments with great confidence. An Affair of State has attracted the lion's share of attention in the media for its assertion that the president was clearly guilty of perjury — in The New York Review of Books, Dworkin even accused Posner of possibly violating the Code of Conduct for United States Judges by commenting publicly on "pending or impending" cases.

But Problematics has struck many insiders as the more revealing document in the often perplexing archive of Posner's worldview. Certainly his condemnations of moral philosophy are passionate. "I hate the moral philosophy stuff. It is theology without God," he says bluntly. "I don't like theology with God, I don't like theology without God. It's preachy, it's solemn, it's dull. It's not my cup of tea at all." Jules Coleman, a Yale law professor, feels Problematics is crying out for some sort of deeper explanation: "It's a multipronged, migraine headache-inducing attack on moral philosophy. It's so vehement, and it comes from so many different angles, that you feel like applying appropriate social science to the investigation of it — namely, what's going on inside this guy's head?"

Born in New York City in 1939, Posner grew up in the city and its suburbs. His mother was "stridently left-wing," he says, and had many radical friends, including the couple who adopted the children of Julius and Ethel Rosenberg. In fact, as a youngster, Posner gave away his train set to the Rosenbergs' children, Michael and Robby. Posner's father was a lawyer, and, growing up, Posner "always had it in the back of my mind that I might end up being a lawyer," though he majored in English at Yale. After graduating in 1959, he went on to Harvard Law School, became president of the Harvard Law Review, and finished first in his class. In 1962, he went to Washington, D.C., to clerk for a year with the great liberal Supreme Court justice William Brennan.

Though he was a self-described "standard liberal type" at the time, Posner remarks that "if I had been picked to clerk for a conservative judge — that would have been Harlan then — that would have been fine also. I wasn't any kind of zealot." During his clerkship, Posner showed early hints of his gifted legal mind. On one occasion, he mistook Brennan's instructions, and drafted an opinion arguing the exact opposite of what Brennan had intended. Posner's statement was so persuasive that Brennan and his colleagues changed their minds and signed it.

If Posner had defining enthusiasms as a young law clerk, they were economic ones. He discovered his interest in the intersection of economics and the law while cite checking an article on merger law and then while working on a major antitrust case with Brennan, United States v. Philadelphia National Bank (1963). He left his clerkship to spend two years at the Federal Trade Commission, followed by two years working for Thurgood Marshall in President Lyndon Johnson's solicitor general's office. "My last job in Washington," Posner recalls, "working on the staff of a telecommunications task force, was very economics-intensive, so by the time I started teaching, I did think I was going to do law and economics. I don't think it was even called that then, but I did want to apply economics to the law."

Previously in LF All the President's Men: A historians' petition takes on the impeachment process. Showdown!: The new legal scholarship on "the embarrassing Second Amendment" is fired upon by historians.

The law and economics movement began from the observation that in a perfectly free market, every deal advances the interests of both its parties; otherwise, someone would opt out. Furthermore, since both parties gain something of greater value to them through the transaction, the total amount of social wealth increases. On the strength of those insights, Posner suggested that common law — the judge-made body of decisions that governs tort, property, and contract law — can be understood as a tool for promoting social wealth. A law that interferes with free bargaining will draw challenges in the courts, since it constrains people from buying and selling as they wish and thus from advancing their interests. On the other hand, a law that does not obstruct free bargaining will remain on the books, season, and become precedent.

From these premises, Posner drew some provocative conclusions. When deciding truly novel cases, judges should not think of their task as preventing harm by honoring rights, but rather as distributing rights and harms in the same way that a free market would have done. For instance, rather than making slippery arguments about which party to a property dispute has an abstract claim to the contested goods, a judge ought to determine which party would have acquired the right to the property by bargaining for it in a perfectly free market. When judges distribute rights in the way that an ideal market would, they, like the market, are maximizing total social wealth.

Posner further argued that legislators should be concerned principally with protecting people's ability to bargain freely, and not with redistributing wealth. Indeed, from the law and economics standpoint, redistribution actually decreases total social wealth, since it takes something from those who value it and puts it in the service of those who, not having transacted for it, will not feel the market pressures to wring the most efficient use out of it.

These were bold, politically charged proposals, and they infuriated many liberals and leftists in the academy. In 1980, the Harvard legal historian Morton Horwitz predicted in the Hofstra Law Review that "the economic analysis of the law has 'peaked out' as the latest fad in legal scholarship." Over the next twenty years, however, Horwitz's prediction proved stunningly wrong. Virtually every major law school today has a program in law and economics, as well as an economist on the faculty. And although Posner was never able to convince the legal academy that economics explains the history and hidden logic of the law, he and many other legal scholars, including his Chicago law school colleague Richard Epstein, maintain allegiance to the idea. Certainly the policy suggestion that the law ought to promote greater economic growth is very much alive. "There have been a lot of faddish movements in the law," Posner says. "Critical legal studies, postmodernism, critical race theory. Some leave little deposited insights; they directed our attention to aspects or perspectives that we hadn't seen." But, he notes with satisfaction, "only law and economics has had real staying power."

The staying power has not been merely academic. Antitrust law, for instance, stands as the shining example of success to proponents of law and economics. In the early days of the Sherman Antitrust Act (1890), Posner points out, the "very goal of antitrust policy was obscure and contested — was it to promote economic efficiency or to reduce the power of big business? It is hard to do both." With a few exceptions, antitrust law until the 1970s was driven by what Posner calls "populist" sentiment about the inherent evil of bigness, rather than by any empirical understanding of whether specific legal decisions actually improved economic efficiency. But with the rise of law and economics in the 1970s and the Reagan revolution of the 1980s, antitrust law effectively became a branch of applied economics, and economic efficiency became the only widely accepted goal of antitrust efforts. "On its frontiers, the law and economics movement looks wacky," concedes Harvard law professor and cyberlaw expert Lawrence Lessig, who clerked for Posner from 1989 to 1990, "but this is the nature of a frontier, not the movement.... We are all law-and-economists now."

Unsurprisingly, Posner's conservative economic views caught the eye of President Reagan, who nominated Posner to the bench in 1981. In retrospect, Posner was probably lucky to have been nominated so early in Reagan's term. "I think I was the second nominee to the federal courts of appeals by Reagan and the first professor," he remembers. "So it wasn't yet realized that he was trying to fill up the bench with conservative professors." Nor was it likely that the senators realized that in the Journal of Legal Studies, Posner had discussed buying and selling babies on the free market in lieu of government- regulated adoption, or that he had argued that the archetypal antitrust infraction of predatory pricing rarely, if ever, exists. Without having to pass through Borkian rings of fire, Posner took his seat on the bench, though he continued to teach a partial course load at Chicago and to write book after book elaborating his economic approach to the law. There was only one sticking point: How could such a radical thinker function as a responsible judge?

As ambitiously technocratic as Posner's law and economics program may seem, his practice of judging has a more commonsensical, pragmatic bent. In recent years, he has overruled a controversial Illinois statute that prohibited candidates for judicial office from taking political stands on issues that might come before them as judges, and he dissented when his colleagues voted to uphold bans on "partial-birth" abortions, arguing that the laws were a blatantly unconstitutional restriction of a woman's right to abortion. He treats economic research as only one especially powerful tool among the many from which judges choose.

"Judges have a terrible anxiety about being thought to base their opinions on guesses, on their personal views," Posner has said. "To allay that anxiety, they rely on the apparatus of precedent and history, much of it extremely phony." By contrast, he believes that a pragmatic, reasonable judge will weigh the available evidence, including the relevant social science, to determine which decision produces results that best further society's goals. "I do think judges can and should get away with a lot more candor," he explains, "so that the public sees what a court is — not geniuses, or even particularly erudite people, but just lawyers trying to give some reasonable ground for their opinions."

Posner's own considerable candor has made for some highly unusual opinions. Back in 1990, the judges of the Seventh Circuit decided the case of Miller v. Civil City of South Bend. At issue in Miller was the constitutionality of an Indiana public-indecency statute prohibiting "the showing of the female breast with less than a fully opaque covering of any part of the nipple, or the showing of covered male genitals in a discernibly turgid state." Darlene Miller and several other nude dancers affiliated with the Kitty Kat Lounge of South Bend, Indiana, challenged the constitutionality of the statute on grounds that "non-obscene nude dancing of the barroom variety, performed as entertainment," was a form of artistic expression protected by the First Amendment.

The court decided in favor of Miller, and Posner concurred with the majority on the grounds that nude dancing is a form of expression entitled to limited protection under the First Amendment. But his separate opinion was very much his own. It seemed he was not particularly interested in the legalistic arguments advanced by either side in the case:

The true reason I think for wanting to exclude striptease dancing from the protection of the First Amendment is not any of the lawyers' classification games... such as expression versus nonexpression, ideas versus emotions, art versus entertainment, or speech versus conduct. It is a feeling that the proposition, "the First Amendment forbids the State of Indiana to require striptease dancers to cover their nipples," is ridiculous. It strikes judges as ridiculous in part because most of us are either middle-aged or elderly men, in part because we tend to be snooty about popular culture, in part because as public officials we have a natural tendency to think political expression more important than artistic expression, in part because we are Americans — which means that we have been raised in a culture in which puritanism, philistinism, and promiscuity are complexly and often incongruously interwoven — and in part because like all lawyers we are formalists who believe deep down that the words in statutes and the Constitutions mean what they say, and a striptease is not a speech. But the element of the ridiculous is not all on one side. Censorship of erotica is pretty ridiculous too. What kind of people make a career of checking to see whether the covering of a woman's nipples is fully opaque, as the statute requires?... The history of censorship is a history of folly and cruelty.

In a seminar at the Chicago Law School, surrounded by a handful of students and fellow Chicago law professors — Cass Sunstein, Richard Epstein, Martha Nussbaum, David Strauss, and others — Posner presents a paper on privacy law. Sitting still and slightly stooped, he broaches the topic by sketching his theory of the self that privacy law is designed to protect. People create useful personas, he explains, that facilitate advantageous transactions. Privacy law protects these personas from being exposed as fronts. This deception, Posner argues, though not exactly fraud, is certainly not in the interest of the larger public good. Thus, legal thinking about privacy has reason to begin with a prejudice against privacy rights rather than in favor of them.

Strauss is the first to object. Such reasoning, he proposes, might justify forcibly removing a kidney from someone if it turns out that the organ could be used to synthesize helpful drugs for others. In certain cases, a violation of privacy, Strauss suggests, is akin to a violation of one's actual person. "Oh, that's different," Posner says dismissively. "Is it?" demands Strauss. Posner pauses thoughtfully for a moment. "Isn't it?" he replies. Everyone laughs. "Do I have the burden of proof here, or do you?"

Posner's critics often protest that his attacks are flippant and idiosyncratic — especially when he takes on his latest bugbear, moral philosophy. Even Posner admits that his assault on ethics has a sharp personal edge, but the case he marshals against it, he insists, stands independent of his own "visceral dislike" of the discipline. The structure and vocabulary of academic moral discourse, he believes, are so spongy that it's impossible to determine whether any of its claims are right. Further, even if moral theory could demonstrate moral truths, Posner does not believe its arguments would, as a matter of psychological fact, convince people to change their behavior or beliefs. "If they can show me cases where moral reasoning has actually changed people's views," he challenges, "well, that's fine; but there don't seem to be any of those cases."

In Posner's mind, the most vivid example of the irrelevance of moral philosophy to the law was the so-called Philosophers' Brief, a defense of the right to assisted suicide submitted to the Supreme Court by a dream team of liberal moral philosophers: Ronald Dworkin, Thomas Nagel, Robert Nozick, John Rawls, Thomas Scanlon, and Judith Jarvis Thomson. Invoking the moral principle of individual autonomy and a philosophical argument against the distinction between acts of commission and acts of omission, the brief was intended to bolster the case for euthanasia. But all nine justices voted to uphold state statutes banning the practice, overturning lower-court decisions and apparently ignoring the Philosophers' Brief entirely. None of the brief's philosophical claims was debated by the Court in its deliberations. In The Problematics of Moral and Legal Theory, Posner gleefully took note of this, pronouncing the philosophers' effort elitist and shameful. "People favoring the status quo," he recounted, "had the strength of inertia and intense conviction behind them, while the people favoring change [Dworkin et al.] were by and large the wealthier and better educated, who usually get their way in the political process as elsewhere."

But can moral philosophy be dismissed so easily? For Dworkin, who believes that the law consists not merely of rules imposed by legislatures but also of underlying moral principles that judges have a responsibility to draw on, Posner's effort to debunk moral theory amounts to little more than infuriating sleight of hand. Not only, he argues, does Posner rest his case on an empirical claim — that moral arguments never change people's minds — for which he offers nothing but conjecture and anecdotal support, but his pragmatic view of judging and morality begs all the important questions for which it is offered as a solution. After all, Posner argues that a novel judicial decision or moral claim is justified only if it advances the goals of a society. Therefore, he needs to be able to identify what the goals of society are. If he appeals to a higher notion of the good in order to do that, then he will have to offer a moral theory of his own. But if he suggests that the goals of society are just the ones that people happen to have, he is presuming a consensus whose absence is precisely the reason moral theory or judicial opinions are needed in the first place. "Posner's argument," Dworkin wrote in his Harvard Law Review response to the "Problematics" lectures, consists of "empty calls for action in pursuit of goals it cannot even describe, let alone justify.... [I]t encourages forward-looking efforts in search of a future it declines to describe."

Ironically enough, Posner did not always look on moral philosophers so harshly: Indeed, in his earlier years, he aspired to the calling himself, setting out to be an ethicist of pure capitalism, the Immanuel Kant of the free-market counterrevolution. In a Journal of Legal Studies article, "Utilitarianism, Economics, and Legal Theory" (1979), and a Hofstra Law Review article, "The Ethical and Political Basis of the Efficiency Norm in Common Law Adjudication" (1980), Posner ambitiously sought to give free-market economics a moral foundation. Why, he demanded, is wealth maximization a good thing?

In an intriguing move, the young Posner suggested that the market's maximization of wealth was not only an effective way of realizing a society's goals but a valuable moral principle in its own right. "It seems to me that economic analysis has some claim to being regarded as a coherent and attractive basis for ethical judgments," he wrote. By this, he did not mean that wealth itself was the sole thing that society valued. Rather, he claimed that because markets place goods and rights in the hands of those who value them most, a free market — and legal decisions that mimic the distribution of rights in market transactions — will necessarily produce a compelling and just distribution of goods and rights.

Dworkin, Jules Coleman, and Anthony Kronman waged a battle against Posner's moral project, and Posner, by his own admission, lost badly. "Economists," Posner noted in his "Problematics" lectures almost twenty years later, "have sometimes tried to make economics a source of moral guidance.... These are doomed efforts." In a modest footnote, he added simply, "I speak from experience," and then cited Dworkin's rebuttal. "There was no doubt that Dworkin and I, and to a lesser extent Tony Kronman, basically wiped the floor with him," says Coleman.

The problem with Posner's argument was glaring. The principle of wealth maximization dictates that goods and rights are to be distributed to those who value them most. At the same time, the value you place on a right is determined by how much you are willing to pay while bargaining for it, and how much you are willing to pay for something often depends on how much money you already have. By this logic, the principle of wealth maximization suggests that there is no justification for making those who are already wealthy share what they have; it even suggests that their wealth alone is justification for giving them more. Worse, people with no wealth have no rights. Posner had tried to plug these gaps by arguing that wealth maximization was actually a principle for explaining how basic rights are originally distributed in, say, a hypothetical auction. But the unsettling idea that a person is entitled to a right only insofar as she can produce the wealth needed to acquire it recurred here as well. Posner's theory was, in effect, a tautology: Maximizing wealth was good because it created a just distribution of rights, and the reason that distribution was just was because it maximized wealth.

Having failed to provide a solid philosophical defense of wealth maximization, Posner fell back on a more limited claim. He argued that a wealth-maximizing society would as a matter of well-established fact have an attractive mixture of everything else — welfare, autonomy, respect, equality. "This is an empirical claim for which he has absolutely nothing resembling evidence, other than hypotheticals and suppositions," Coleman charges. "As a social scientist one would think you could do better on this.... On the face of it, maximizing wealth doesn't seem to connect in any interesting way to any of these things."

After abandoning the effort to give law and economics an ethical foundation, Posner turned toward the more modest tradition of pragmatism: We don't need universal moral foundations, only ad hoc solutions to practical problems. He insists that he has reached his present position on account of his subsequent years of experience, not as a fall-back plan following his unsuccessful philosophical project. "Dworkin's criticisms were good," he acknowledges, "but those were criticisms from within moral philosophy. [My present] skepticism comes from another ten or fifteen years of observing the indeterminacy of this kind of philosophical debate."

Today's Posner is more inclined to criticize the presumptions of high-minded theory. He takes great pleasure in citing The Altruistic Personality: Rescuers of Jews in Nazi Europe (1988), by Samuel Oliner and Pearl Oliner, a statistical study of German and Polish rescuers of Jews that shows that higher levels of education were negatively related to the propensity to rescue. The study lends credence to Posner's hypothesis that intellectual fluency allows people to rationalize inactivity. He is also fond of using the findings of evolutionary biology to suggest that morality, to the extent it is prevalent and shared, is encoded in our genes: True examples of moral or self-sacrificing behavior "may illustrate an instinctual" extension of our evolutionarily ingrained impulse to protect our kin.

The consequences of Posner's pragmatic view of morality can be peculiar, to say the least. "One reason for the widespread condemnation of the Nazi and Cambodian exterminations," Posner wrote in The Problematics of Moral and Legal Theory, "is that we can see in retrospect that they were not adaptive to any plausible or widely accepted need or goal of the societies in question. The genocidal policies that the United States pursued toward the American Indians were adaptive and so receive less criticism, especially as Americans who are not Indian...are the beneficiaries of those policies." But Judge John T. Noonan Jr. of the Ninth Circuit Court of Appeals noted in his response to "Problematics" in the Harvard Law Review: "No one I know criticizes Hitler because after twelve years of power he came to a bad end; he is criticized because he was a bad man doing bad deeds."

If Posner's debunkings of morality can sound outrageous, some speculate that they have extra-intellectual roots. For Nussbaum, Posner's urge to demystify ethics is partly rooted in his childhood. Posner's view of morality, she feels, "may well have something to do with having grown up as the child of a communist mother who...took his electric trains to give them to the Rosenberg children. I feel sometimes as if I am being treated by a brilliant and rebellious child. He wants to elude this parent's sermonizing, but he also doesn't want the parent to fail to notice him. So he sets out to shock and provoke, and the persistence of his shocking behavior is itself a way of engaging very deeply with the parent's sermons."

Her personal experience, Nussbaum notes, was exactly the opposite. "On a panel on literature...I asked him whether he could imagine that one might turn to literature for a joyful escape from a world of injustice into a world of justice," which was the situation for her, growing up "in an amoral wealthy environment and reading Dickens." Posner, she recalls, "stood in utter silence at the podium for about thirty seconds, and then, in his quiet way, simply said, 'No.' I would trace this, again, to his childhood experience: Whereas for me morality was a joyful escape from my father's amorality, for him an amoral stance was a gleeful escape from his mother's moralism."

"Like most of us," Coleman adds, "the people who are the strongest influences on our lives influence us in one of two directions: either by abduction or by repulsion. I think he fell in the repulsion category. I mean, it's like trying to kill your father."

However subterranean and personal the origins of Posner's views about moral philosophy may be, they are also arguably well-suited to a sitting judge. Many law professors, even those sympathetic to moral philosophy in general, feel that Posner is dead right that moral theory has no place in the law. The liberal Chicago law professor Cass Sunstein, for one, believes that "courts do not mostly make or engage abstract, theoretical arguments, and that is good, because usually they don't have to engage those arguments and they're likely to make mistakes if they do." Judges, after all, want to resolve cases by basing their decisions on the narrowest grounds possible, whereas philosophers want to base their arguments on the broadest grounds possible and contribute fuel to ongoing debates.

For Posner, though, the trouble with overly ambitious intellectuals goes far beyond their mischief in the courtroom. Equally egregious, he thinks, is the tendency for academics to take strong stances as "public intellectuals." By speaking outside their areas of expertise, academics "border on misrepresentation," he argues. "I have that view about Dick Rorty talking about labor unions and related economic issues," he notes. "He's a terrific philosopher and a brilliant person, but he has no relevant knowledge to talk about labor unions and the economy." For others, including Nussbaum, Hilary Putnam, and Noam Chomsky, he has the same criticism: "A lot of these people feel that in their primary field they're very rigorous and that when they go into these other fields, these fields are occupied by less rigorous people, and so they should have no trouble obtaining a minimal level of expertise. Which is wrong."

It might strike some as ironic that a scholar as wide ranging and interdisciplinary as Posner would advance such a charge, but he sees a distinction between what he does and what Rorty and others do. "If the Times or The New Republic asks me to write about something which I think I know something about," he explains, "and if I can write in a way that is interesting to a general audience, I'm happy to do that... [But] my sense of a public intellectual is someone who is more programmatic and trying to influence public policy."

Posner also likes to decry the hypocrisy of philosophers whose strongest moral views apply to the world afar. Academic moral philosophers, he notes, "have very safe positions in an institution which could be regarded as radically unjust." In his telling, academic stars become "pampered, cosseted full professors with light teaching loads and job security," which "makes them unavailable as charismatic leaders." If they want to change the world, Posner suggests they go out and do something about it. But "just to be a professor and preach this stuff and not even notice how the instructors and the TAs are living — it deprives you of any moral authority."

By contrast, Posner has every right to be proud of his own dealings with those around him. According to Coleman and countless others, he is a stunning model of the attentive professional, responding diligently, promptly, and exhaustively to papers, proposals, and argumentative e-mails from professors and students of all rank and caliber. "He is socially engaging, very professionally responsible," says Coleman. "And I can sympathize with [his] sentiment that there is often a troubling dissonance between the lives individuals lead and the ones they prescribe for others. But to me, this is all irrelevant with respect to the question whether or not they are good moral philosophers."

Posner's professional dedication reflects a combination of argumentative fierceness and humility. "After I left him as a clerk," Lawrence Lessig recalls, "he and I had a particularly ferocious exchange, and it had got extremely heated. I wrote him a note apologizing, saying that I was out of line to have been so extreme. His response was classic Posner. He said, ėThat's absurd. I spend too much of my life with people being overly deferential to me. It's not a good thing for judges to live such a life, and it's important to have critics who are direct and honest and strong in their criticism.' And I think he is sincere about that."

It's nice to imagine that at the heart of Posner's prodigious achievement lies this humble, workaday ethic of professional conduct and the pragmatic goal to help society achieve its stated aims. In important, everyday ways, this image is not far from the truth. And yet there remains a puzzling, invigorating friction between his homespun, empirically oriented, ad hoc demystification of the world and his prolific, single-minded sense of mission, his hard-line challenges to common pieties, his almost flamboyant claims of humankind's inherent limitations.

Nussbaum offers a telling anecdote. One day, over lunch, Posner shared a curious discovery: In reality, he explained, he is a romantic and she is a utilitarian. The irony, she notes, is that "he is known as the paradigmatic Utilitarian, and I've portrayed him as Mr. Gradgrind; I am thought to be a paradigmatic Romantic." But Posner had realized that Nussbaum, like many other moral philosophers, essentially thinks that "people should be made happy, and that is what is important in life," she remembers. "He, like Nietzsche, thought that life was all about struggle and suffering, in which not the greatest happiness of the greatest number, but heroic and creative achievement are the most important things." That is not, in any sense, an optimistic vision, but no doubt for Posner it is the most pragmatic one.

James Ryerson is associate editor of LF and managing editor of Arts & Letters Daily. His article "Games People Play: Rational Choice With a Human Face" appeared in the December/January issue of LF.