Friday, September 19, 2014

A New Study of Chimpanzee Warfare: Hobbes Versus Rousseau


 A chimpanzee war party of males on patrol typically moves in a single-file pattern.

I have written a series of posts on the debate over chimpanzee warfare, which can be found here and here. 

As I have indicated, this is ultimately a debate in political philosophy between Hobbesians who argue that war is rooted in human nature and Rousseaueans who argue that war is a purely cultural trait and that the original state of nature was peaceful.  Since chimpanzees and bonobos are the living primates most closely related to human beings, the dispute over whether chimps and bonobos are naturally warlike or peaceful becomes part of the dispute over the evolutionary roots of human warfare.

A new article favoring the Hobbesian position has just been published in Nature:  Michael L. Wilson, et al., "Lethal Aggression in Pan Is Better Explained by Adaptive Strategies than Human Impacts," Nature 513 (18 September 2014): 414-417.  Here's the abstract:
"Observations of chimpanzees (Pan troglodytes) and bonobos (Pan paniscus) provide valuable comparative data for understanding the significance of conspecific killing.  Two kinds of hypotheses have been proposed.  Lethal violence is sometimes concluded to be the result of adaptive strategies, such that killers ultimately gain fitness benefits by increasing their access to resources such as food or mates.  Alternatively, it could be a non-adaptive result of human impacts, such as habitat change or food provisioning.  To discriminate between these hypotheses, we compiled information from 18 chimpanzee communities and 4 bonobo communities studied over five decades.  Our data include 152 killings (n = 58 observed, 41 inferred, and 53 suspected killings) by chimpanzees in 15 communities and one suspected killing by bonobos.  We found that males were the most frequent attackers (92% of participants) and victims (73%); most killings (66%) involved intercommunity attacks; and attackers greatly outnumbered their victims (median 8:1 ratio).  Variation in killing rates was unrelated to measures of human impacts.  Our results are compatible with previously proposed adaptive explanations for killing by chimpanzees, whereas the human impact hypothesis is not supported."
This is impressive evidence for the Hobbesian argument.  But as indicated by a news story in The New York Times and a  blog post by Marc Bekoff, the Rousseaueans are not ready to surrender.  Four points need to be made here.

First of all, notice that after 50 years of studying 22 communities, there have been only 58 directly observed killings and 41 inferred.  Even if one concedes that intraspecific killing occurs, one can see that it is remarkably rare, and generally these animals are peaceful and cooperative.  The Hobbesians have to admit this.

The second point here for the Rousseaueans is that the bonobos still look even more peaceful than the chimps.  And that's why the hippie bonobos are so loved by the Rousseaueans.

The third point is that Rousseaueans like Brian Ferguson will argue that this study does not go deeply enough into the long history of human disturbance of chimpanzee habitats to see its effects.  Ferguson is writing a book--Chimpanzees and War--that will elaborate his case for the Rousseauean position.  Meanwhile, Ferguson has written a good response to the Nature article.

The final point is that even if lethal coalitional raiding is a natural adaptation for chimpanzees and human hunter-gatherers, complex human warfare as it arose first with bureaucratic states is a largely cultural invention that can be changed through cultural evolution.  Richard Wrangham, one of the senior authors of the Nature article, has stressed this.  And, indeed, if Steven Pinker is correct, the cultural history of recent centuries has shown declining violence.

Sunday, September 14, 2014

How Adam Smith Predicted the Financial Crisis of 2008

As a friend and follower of Ayn Rand and then Chairman of the Federal Reserve, first appointed by Ronald Reagan, Alan Greenspan was regarded as one of the leading proponents of free-market economic thinking.  But in October of 2008, as the global financial crisis created a deep recession, Greenspan admitted at a Congressional hearing that he was in "a state of shocked disbelief" that free markets had failed to steer the economy away from disaster. 

Matt Ridley (now Viscount Ridley, and a member of the House of Lords in Great Britain) has also, like Greenspan, been a proponent of free markets and libertarian thought.  In The Rational Optimist, he has even argued that the entire history of human evolution can be understood in the terms of Adam Smith as the progressive expansion of trade and the division of labor as spontaneous orders that foster wider and more productive cooperation.  Ridley's scorn of government verges on anarchism.  

And yet, he was quick to call for the help of government when he needed it.  He was the non-executive chairman of the Northern Rock bank from 2004 to 2007, having joined the board of the bank in 1994.  The bank fell into crisis in 2007 after making risky investments with money borrowed from other banks, and it became the first British bank since 1878 to face failure from a run of withdrawals by depositors.  The bank was forced to petition the Bank of England for a bailout.  Ridley was forced to resign.  In response to this scandal, some of Ridley's critics accused him of hypocrisy. 

In The Rational Optimist, Ridley writes one passage about this.  He expresses his regret, and explains: "The experience has left me mistrustful of markets in capital and assets, yet passionately in favour of markets in goods and services. . . . Speculation, herd exuberance, irrational optimism, rent-seeking and the temptation of fraud drive asset markets to overshoot and plunge--which is why they need regulation, something I always supported. (Markets in goods and services need less regulation.)" (9).  Previously, I have written a post on this.


Experiences like this have created a general belief that the financial crisis showed the failure of Adam Smith's optimistic vision of how the "invisible hand" could achieve prosperity and social stability through the spontaneous orders of free markets.

This belief is mistaken, however, because it ignores Smith's deep pessimism about whether his "system of natural liberty" was achievable, given the propensities of human nature to foolishness, fraud, and injustice that create economic crises.  When one looks at his reasons for pessimism, one can see that he foresaw all of the human mistakes that led to the financial crisis of 2008 and the Great Recession that it created. 

This also shows Smith's understanding of how markets depend on morals, so that markets fail without a healthy moral culture.  That explains why Smith saw political economy as part of moral philosophy, and thus his Wealth of Nations needs to be read together with his Theory of Moral Sentiments.

When one reads the whole of Smith's published writing with care, one of the main themes that emerges--perhaps surprisingly--is that Smith was pro-market but not pro-business.  As economist John Kay has noted, "both supporters and critics of the market economy have often confused policies that are pro-business with policies that are pro-market," and this has led to serious policy mistakes, while also weakening the moral and political legitimacy of market economies. 

Elaborating ideas that can be found in Smith, Kay sees three elements in the market economy: prices as signals for allocating resources, markets as a process of discovery that allows for adaptation to chaotic change, and diffusion of political and economic power.  The success of a market economy with all of these elements is manifest as what Kay calls "disciplined pluralism": "When prices act as signals, decentralized enterprises and decentralized information are brought together to create a coherent result.  Markets as a process of discovery are based on freedom to experiment, combined with discipline: unsuccessful experiment is acknowledged and terminated.  Markets as a means of decentralizing power are the determinant of the areas where politics and economics meet."

Smith makes it clear that rich and powerful businesspeople--merchants, manufacturers, and bankers--don't like this kind of market economy that diffuses and decentralizes power, because they want to use their concentrated power to engage in rent seeking by extracting wealth created by other people rather than creating it themselves.  Rent seeking can never be completely eliminated.  But the success of a market economy depends on limiting it.  The financial crisis was the product of too much rent seeking.

Kay observes:
"Rent seeking takes, and has taken, many forms--castles on the Rhine, the Wars of the Roses; ten per cent on arms sales, or seven per cent on new issues; awarding yourself control over former state assets, stealing the revenues from your country's resources deposits, seeking protection from foreign competition, blocking market access by new entrants; winning sinecures or overpaid positions by ingratiating oneself with public servants or corporate employees.  The mechanisms of rent seeking range from the application of armed force to victory in democratic election; the methods pursued range from lobbying on Capitol Hill and in the restaurants of Brussels, through access to the King or the Chief Executive."
I have been thinking about this while teaching my graduate seminar this semester on Smith.  Some papers by Maria Pia Paganelli have been helpful to me--particularly, "Is a Beautiful System Dying? A Possible Smithian Take on the Financial Crisis," The Adam Smith Review, 6 (2011): 269-282.  Much of what follows here draws from her article.

In Book IV of The Wealth of Nations, Smith refutes two false systems of political economy--the mercantile system that assumes that money or gold and silver is the sole or primary source of wealth and the agricultural system that assumes that land is the sole or primary source of wealth.  Both systems require that government enforces preferences and restraints on trade that favor some kinds of economic activity over others.  Such governmental intervention grants unfair privileges to those selfish interest groups that have influence over the government, and this violates the public interest, because it reduces the productivity of land and labor below what it would have been if economic activity had been free from such intervention.

At the end of Book IV, he concludes:
"All systems either of preference or of restraint, therefore, being thus completely taken away, the obvious and simple system of natural liberty establishes itself of its own accord.  Every man, as long as he does not violate the laws of justice, is left perfectly free to pursue his own interest his own way, an to bring his industry and capital into competition with those of any other man, or order of men.  The sovereign is completely discharged from a duty, in the attempting to perform which he must always be exposed to innumerable delusions, and for the proper performance of which no human wisdom or knowledge could ever be sufficient; the duty of superintending the industry of private people, and of directing it towards the employments most suitable to the interest of society" (Liberty Fund edition, 687).
According to the system of natural liberty, the government has three duties: the military defense of society against other societies,  securing the administration of justice to protect each individual against the injustice and oppression of other individuals, and erecting and maintaining certain public works and public institutions necessary for the public good that would never be erected or maintained by private individuals.  Book V lays out how government might fulfill these three duties.

The careful reader of The Wealth of Nations will notice, however, that this "natural system of liberty" does not really arise naturally.  In fact, Smith admits that "perfect liberty and perfect justice" is unattainable (674), that expecting to establish complete freedom of trade is utopian because it's opposed by public prejudices and private interests (471), that rich merchants and manufacturers "naturally" seek monopolistic privileges to satisfy their natural concern for their own self interest (462), that restrictions on the freedom of global trade satisfy some natural passions (467), and that in some circumstances, it is advantageous to restrict free trade to favor domestic industry (463).

 Smith also admits that the public interest requires governmental restraints on banking transactions, although these restraints are "in some respect a violation of natural liberty."  He explains: "these exertions of the natural liberty of a few individuals, which might endanger the security of the whole society, are, and ought to be, restrained by the laws of all governments; of the most free, as well as of the most despotical.  The obligation of building party walls, in order to prevent the communication of fire, is a violation of natural liberty, exactly of the same kind with the regulations of the banking trade which are here proposed" (324).

Smith suggests that what one sees in banking and financial systems generally are the impediments to a natural system of liberty that come from the distorting effects of three propensities of human nature.  What he says about these three propensities goes a long way towards explaining the recent financial crisis.

The first troublesome propensity is the tendency of many human beings to irrational risk-taking, because they overestimate their chances of success and underestimate their chances of failure.  Smith observes that "the chance of gain is by every man more or less over-valued, and the chance of loss is by most men under-valued" (WN, 124-25).  This creates problems in lending markets.  Borrowers are too optimistic about their prospects for paying back their loans, and lenders who are rewarded for each loan they issue ignore the risks incurred in their loans.  This was a big part of the mortgage crisis.  Too many borrowers were asking for mortgages they could not repay, and too many lenders were giving out loans that were too risky.  Both groups assumed that housing prices would go up perpetually without the bubble ever bursting.  For this reason, Smith proposed regulations on lending by banks, even though this was a violation of natural liberty.

Smith thought that the foolish optimism of human beings about their luck was illustrated by their gambling on lotteries (WN, 125).  Similarly, as I indicated in my post on John Kay's lecture at the MPS conference in the Galapagos Islands on evolution and liberty, he has observed that many of the casino gamblers in London are successful entrepreneurs who play games of pure chance (like roulette and black jack) as if they know they're going to win.  They're irrational risk-takers who exaggerate their control over things.

The problem irrational risk-taking in banks and other financial institutions extending too much credit is exacerbated by excessive concentration of financial power.  When firms become "too big to fail," they are not punished for their imprudent decisions by going into bankruptcy, because they will be saved by governmental intervention.  For the free market economy to work in financial markets, there must be many small banks and financial institutions, which is what Smith recommends (WN, 329).  Allowing a bank to fail teaches bankers a lesson.  This needs to be done, Smith observes, because banks often do not understand their own interests, and they need to be taught to be prudent (WN, 300-21).  The failure of a small bank is not a great shock to the economy.  But if banks grow too large, their failure is too great a shock for the public good.

The second troublesome propensity is the tendency for our moral sentiments to be corrupted by our disposition to admire the rich and the great (TMS, 61-66, 226, 252-53).  The massive financial frauds of recent years can be explained by this tendency.  When deceptive financial practices yield billions of dollars of wealth, and when "the great mob of mankind are the admirers and worshippers, and, what may seem more extraordinary, most frequently the disinterested admirers and worshippers, of wealth and greatness" (TMS, 62), then it should not be surprising that great financial frauds are committed.

The success of financial transactions depends upon a moral culture of trust, because it depends on promise-keeping.  Daniel Friedman has written:  "Financial markets are where promises are traded: borrowers sell new promises to the highest bidder in the primary market, and investors buy and sell old promises in the secondary market" (Morals and Markets: An Evolutionary Account of the Modern World, 2008, p. 100).  When moral norms of trust decay, the financial system collapses.

The third troublesome propensity is the tendency for human beings to form factions to advance their special interests at the expense of the public interest.  (Here is where James Madison picked up much of his thinking about the "problem of faction.")  "Sometimes the interest of particular orders of men who tyrannize the government," Smith warns, "warp the positive law of the country from what natural justice would prescribe" (TMS, 341).  "To hurt in any degree the interest of any one order of citizens, for no other purpose but to promote that of some other, is evidently contrary to that justice and equality of treatment which the sovereign owes to all the different orders of his subjects" (WN, 654).

Rich merchants, manufacturers, and bankers show this behavior.  "People of the same trade seldom meet together, even for merriment and diversion, but the conversation ends in a conspiracy against the public, or in some contrivance to raise prices" (WN, 145). 
"The interest of the dealers . . . in any particular branch of trade or manufactures, is always in some respects different from, and even opposite to, that of the public.  To widen the market and to narrow the competition, is always the interest of the dealers.  To widen the market may frequently be agreeable enough to the interest of the public; but to narrow the competition must always be against it, and can serve only to enable the dealers, by raising their profits above what they would naturally world be, to levy, for their own benefit, an absurd tax upon the rest of their fellow-citizens.  The proposal of any new law or regulation of commerce which comes from this order, ought always to be listened to with great precaution. . . . It comes from an order of men, whose interest is never exactly the same with that of the public, who have generally an interest to deceive and even to oppress the public, and who accordingly have, upon many occasions, both deceived and oppressed it" (WN, 267).
Thus, Smith foresaw that big business would always be lobbying government to advance the special interests of big business at the expense of the public interest by engaging in rent seeking (WN, 434, 468, 493-94, 496, 647-48).

For this reason, the greatest enemies of a free market economy are big businesspeople.  This was manifest in the financial crisis of 2008.

Some of my other posts on Adam Smith can be found here, here, here, here, here, here, here, here, here, here, here, here, here, here, here, and here,.

Wednesday, September 10, 2014

Joshua Greene's Global Meta-Tribe: Liberals or Libertarians?

In Moral Tribes: Emotion, Reason, and the Gap Between Us and Them, Joshua Greene argues that while our evolved intuitive morality overcomes the Tragedy of the Commons through cooperation within groups, only an abstract rational morality can overcome the Tragedy of Commonsense Morality through cooperation between groups.  Our evolved intuitive morality is a tribal morality:  we have evolved instincts for cooperating with others in our tribal group in order to better compete with other tribal groups.  Our tribal morality allows Us to prevail over Me.  But now our problem in the modern world is the conflict between Us and Them.  We need to form a global tribe or meta-tribe that can resolve our conflicting tribal loyalties and foster universal cooperation.  To do that, we need a common currency of shared values to which all tribes can agree.  As a utilitarian, Greene believes the only common currency is happiness, which should allow us to resolve tribal disputes by agreeing to maximize happiness impartially.

What kind of political philosophy is best for promoting this trans-tribal pursuit of happiness?  Greene suggests that there are only two candidates--either the collectivism of left liberalism or the individualism of libertarianism (or classical liberalism).  These are the "two global meta-tribes--post-tribal tribes" (334).  He identifies himself as a liberal, because he believes the policies of the liberal tribe tend to make the world happier.  But his commitment to that tribe is weak.  "With the right kind of evidence," he says, "you could talk me out of my liberalism" (334).  He says that he was once a libertarian (385), and he still agrees with many libertarian ideas.  He even identifies the libertarians as "the least tribal people of all, eschewing the moderate collectivism of their modern liberal counterparts" (341).

The libertarians believe that the best way to maximize happiness is to secure the individual liberty to pursue happiness.  As a modern liberal, Greene thinks this is insufficient, because we need the "moderate collectivism" of government intervening in the economy to coerce people to do what promotes the greater good of society.  Greene never elaborates the evidence and argumentation to support this position. 

As far as I can tell, his only argument depends on his comparison of individualism and collectivism through a parable about some tribes of herders.  Here is how he describes the individualist tribe:
"To the north of the forest is yet another tribe.  Here there is no common pasture.  Each family has its own plot of land, surrounded by a fence.  These plots vary greatly in size and fertility.  This is partly because some Northern herders are wiser and more industrious than others.  Many such herders have expanded their lands, using their surpluses to buy land from their less prosperous neighbors.  Some Northern herders are less prosperous than others simply because they are unlucky, having lost their flock, or their children, to disease, despite their best efforts.  Still other herders are exceptionally lucky, possessing large, fertile plots of land, not because they are especially wise or industrious but because they inherited them.  Here in the North, the council of elders doesn't do much.  They simply ensure that herders keep their promises and respect one another's property.  The vast differences in wealth among Northern families have been the source of much strife.  Each year, some Northerners die in winter for want of food and warmth.  Despite these challenges, the Northern tribe has survived.  Most of its families have prospered, some much more than others" (2).
Here is how he describes the collectivist tribe:
"To the south of the forest is a fourth tribe.  They share not only their pasture but their animals, too.  Their council of elders is very busy.  The elders manage the tribe's herd, assign people to jobs, and monitor their work.  The fruits of this tribe's labor are shared equally among all its members.  This is a source of much strife, as some tribe members are wiser and more industrious than others.  The council hears many complaints about lazy workers.  Most members, however, work hard.  Some are moved to work by community spirit, others by fear of their neighbors' reproach.  Despite their challenges, the Southern tribe has survived.  Its families are not, on average, as prosperous as those in the North, but they do well enough, and in the South no one has ever died in winter for want of food or warmth."
Apparently, this collectivist tribe is a socialist society with no markets and very little private property.  Everything is organized by the government of the "council of elders," who are assumed to be selfless managers with the knowledge and virtue to manage everything for the greater good of all.  Most importantly for Greene, no one in this collectivist tribe ever dies from want of food or warmth, while people do die from neglect in the individualist tribe.

Much of what Greene writes in the rest of his book casts doubt on the accuracy of his parable.  First of all, he recognizes that people in collectivist societies often do die from starvation.  In fact, millions of people starved to death under the rule of communists like Stalin and Mao.  And Greene concludes from this that we should "be very wary of people with big plans who say that it's all for the greater good" (168).  "The full-blown collectivism of the Southern herders is dead," he admits, "and the question today is not whether to endorse free-market capitalism, but whether and to what extent it should be moderated by collectivist institutions such as assistance for the poor, free public education, national health insurance, and progressive taxation" (341).

So while he rejects "full-blown collectivism," Greene sees the need for some collectivism so that no one starves to death in the Northern tribe.  But that people will necessarily die from neglect in a free society without a collectivist government is an assumption for which he provides no support.  He assumes that when people take care of themselves in a free society, they won't take care of those who need help.  And yet he contradicts this when he acknowledges that people in an individualist society do feel sympathy for those who need help, and so they are charitable (67-68).  He also concedes that "people living in more market-integrated societies, rather than being hopelessly greedy, tend to be more altruistic toward strangers and more adept at cooperating with them" (98).  Indeed, the history of charity and mutual aid societies in the United States and Great Britain before the establishment of welfare-state programs suggests that people in classical liberal societies will help those who need help through voluntary associations.

It is interesting that Greene ends his book by recommending that his readers should increase their charitable giving to groups like Oxfam International (352-55).  This is surprising, because given what he has said about the need for a collectivist redistribution of wealth, we might have expected him to end his book by calling for more governmental coercion to force people to give away their property to the needy.

It is also surprising that Greene endorses Steven Pinker's argument in The Better Angels of Our Nature that "gentle commerce" and the moral culture of classical liberalism have solved 90% of our problems (97-98).

That evolutionary moral psychology supports classical liberalism is a claim that I have elaborated in some of my posts on Haidt and Pinker here and here.
 

Saturday, September 06, 2014

Churchill's Dilemma and the Neuroscience of Moral Judgment

In 1944, one week after the D-Day landing in Normandy, Winston Churchill faced a moral dilemma that philosophers today recognize as a "trolley problem."

During the evening of June 12/13, the Germans launched the first ten flying bombs or V1s towards London.  For the next few months, thousands would be launched, and over 2,000 reached London.  By the end of August, the British had become adept at shooting them down.  But then the Germans replaced the VI with the V2, a long-distance rocket with a warhead.

Scientists working for British Military Intelligence (MI5) had gathered information about the testing of the V1, and they concluded that the VI bombs often fell short of their targets.  This was confirmed when most of the V1s first launched fell on the neighborhoods of south London rather than on their intended targets in the center of London, which was densely populated and where the main offices of government were located.

Some people in MI5 realized that casualties and damage to the government could be reduced if the Germans could be deceived, so that they would not correct the targeting of the V1s.  The Germans had secret agents in England, but the Germans did not know that all of their agents had become double-agents for the British, and they had been supplying the Germans with misleading information.  The Germans asked their agents to report on the locations where the V1s were landing.  So if their agents reported that many of the V1s were overshooting their targets and landing north of London, the Germans would adjust their targeting so that the flying bombs would actually hit the south of London rather than the center.  People in MI5 recommended this plan to the government.  If it worked, thousands of people in south London would be killed, but many more people in central London would survive.

One of the scientists recommending this--R. V. Jones--knew that this would threaten his own family.  Years later, he explained: "I realized well that what I was doing was trying to keep the mean point of impact in the Dulwich area, where my own parents lived and where, of course, my old school was.  But I knew that neither my parents nor the school would have it otherwise" (Most Secret War, 1978, p. 421).

One member of Churchill's cabinet--Herbert Morrison--vehemently opposed this proposal as an "interference with Providence" that was immoral, because they would be responsible for killing some people who might otherwise have lived.  Churchill, however, accepted the argument that it was better to allow the foreseeable but not directly intended deaths of some people in the south of London if this prevented the deaths of many more people in the center of London.

As David Edmonds has pointed out in his new book--Would You Kill the Fat Man?--this dilemma resembles the trolley problem that I have written about previously.  In the Switch Case, we can prevent a runaway trolley from killing five people on the tracks by switching it onto a side track where it will kill one person.  When presented with this dilemma, most people around the world say they would pull the switch and thus sacrifice one life to save five lives.  That seems close to what Churchill chose in allowing thousands of innocent people to die so that many more could live.

In the Footbridge Case, by comparison, we can save the five people on the tracks by pushing a very fat man off a footbridge onto the tracks, and he's big enough to stop the train.  From a utilitarian point of view, we should decide this case the same way we decide the other case, because in both cases, the killing of one person is morally justified by the greater good of saving five people.  But most people around the world say they would not push the fat man.  And when they are asked to explain their reasoning, they often admit confusion about their motivation, and sometimes they'll say that pushing the fat man just feels wrong, even though the utilitarian principle of taking one life to save five apparently applies here.  (We might imagine Churchill having to decide whether he should personally push some people into the path of a flying bomb to save the lives of others.)

Edmonds and most philosophers today see this as a refutation of utilitarianism, or at least of pure utilitarianism.  Although our moral intuitions sometimes approve of utilitarian reasoning, as in the Switch Case, sometimes we reject utilitarianism, as in the Footbridge Case.

Fervent utilitarians like Peter Singer and Joshua Greene disagree with this.  They insist that maximizing happiness impartially is the fundamental principle of morality.  We all want to be happy, and we don't want to be miserable.  This universal pursuit of happiness becomes moral when we consider it from an impartial perspective.  I think I'm special in valuing my happiness and the happiness of those close to me.  But I can understand that you think you're special in the same way.  I can see, then, that if we are to achieve the benefits of social cooperation, we must recognize that each person's happiness is equal to the happiness of any other, and thus that the happiness of many might count for more than the happiness of few.  So if we are to maximize happiness impartially, we must push the fat man. 

The differences between the Switch Case and the Footbridge Case are not morally relevant, Singer and Greene claim, because all that counts morally are the consequences, which are the same: five lives are rightly saved at the expense of one.  The two cases might be different emotionally, but not rationally.  And morality requires that our rational comprehension of moral principles should prevail over any conflicting emotional responses.

How do we explain the fact that most people think the differences between these two cases really are morally relevant?  One explanation is that most people intuitively apply the doctrine of double effect, which was stated by Thomas Aquinas, and which has been associated with the moral teaching of the Catholic Church.  To explain why we prohibit intentional killing but permit killing in self-defense, Aquinas explained: "One act may have two effects, only one of which is intended and the other outside of our intention."  When we kill in self-defense, the death of the person threatening us is foreseen but not directly intended.  Our direct intention is to defend our life.  Killing the assailant is an unintended side-effect of our action.  So if the assailant were to stop his attack, we would not kill him, and this would be our preference.  If we could remove his threat to our life without killing him that would be the morally preferable choice.

This principle has become a fundamental standard in both domestic law and international law.  Homicide can be justified if the death is a foreseen but not intended side-effect of defending our lives or the lives of others.  In war, it is unjust to directly target innocent people--civilians or soldiers who have surrendered.  But it is just for some innocent people to die as a side-effect of an attack on a military target, as long as there have been reasonable efforts to minimize the danger for innocent people.

A full statement of the principle of double effect has been suggested by John Mikhail: "an otherwise prohibited action, such as battery or homicide, which has both good and bad effects may be permissible if the prohibited act itself is not directly intended, the good but not the bad effects are directly intended, the good effects outweigh the bad effects, and no morally preferable alternative is available" (Elements of Moral Cognition, 149).

Mikhail explains that most people feel that they should not push the fat man off the footbridge, although they would switch the trolley onto the side track and thus kill the man on the track, because they have an instinctive knowledge of the norm of double effect, and they sense that pushing the fat man is intentional homicide, while pulling the switch results in foreseeable but unintentional homicide.

Utilitarians like Greene and Singer argue that this distinction between foreseeing and intending a death is irrelevant to moral judgment: if it is right to kill one person to save five, then it doesn't matter morally whether this killing was directly intended or only a foreseeable side-effect of directly intended action to save the five, because the consequences are the same.

Greene concedes, however, that the human brain has evolved to recognize the principle of double effect.  In Greene's own research, in scanning the brains of people while they pondered trolley problems, he has shown that when people are thinking about the Switch Case, there is increased neural activity in the dorsolateral prefrontal cortex (DLPFC); and when they are thinking about the Footbridge Case, there is increased neural activity in the ventromedial prefrontal cortex (VMPFC) and the amygdala.  The neural circuits in the DLPFC enable cognitive control in which the brain organizes thought and action in accordance with decision rules that might require overriding competing impulses.  The neural circuits in the VMPFC and the amygdala enable strong emotional responses.




So when we are making utilitarian judgments (such as sacrificing one life to save five), Greene infers, our DLPFC is active, and the emotional response in the VMPFC and the amygdala is weak, which is what happens to most people in deciding the Switch Case.  But in the Footbridge Case, the thought of pushing the fat man arouses such a strongly negative emotional response in the VMPFC and the amygdala in most people that the utilitarian judgment is overridden.  Those people who do accept the utilitarian judgment in the Footbridge Case are able to exercise cognitive control in applying the utilitarian decision rule ("Do whatever will produce the most good") while suppressing the emotional inhibition against directly killing someone (Moral Tribes, 116-131). 

Here, then, we can actually see the conflict in the brain between reason and emotion in deciding whether the rights of the individual should take precedence over the greater good.  Greene sees this as supporting his "dual process theory" of moral judgment as based on the interaction between automatic emotions and deliberate reasoning.

It is a mistake, however, to think of this "dual process" in the brain as a sharp dichotomy or conflict between reason and emotion, with utilitarianian judgment requiring reason to conquer emotion.  Green thinks that neuroscience confirms David Hume's argument that reason is the "slave of the passions" (134-37, 184-85, 190-92, 201, 291, 328, 352, 385).  Pure reason by itself cannot move us to action without some motivating emotion or desire.  After all, utilitarianism is rooted in the natural fact that our wanting to be happy, and wanting not be miserable is an evolved gut feeling. 

Greene notes that the DLPFC and the MVPFC are interconnected, and he also observes: "the DLPFC, the seat of abstract reasoning, is deeply interconnected with the dopamine system, which is responsible for placing values on objects and actions.  From a neural and evolutionary perspective, our reasoning systems are not independent logic machines.  They are outgrowths of more primitive mammalian systems for selecting rewarding behaviors--cognitive prostheses for enterprising mammals.  In other words, Hume seems to have gotten it right" (368).

The Footbridge Case sets off emotional alarm bells in our brains in a way that the Switch Case does not.  Why?  Greene explains this through a "modular myopia hypothesis": "First, our brains have a cognitive subsystem, a 'module,' that monitors our behavioral plans and sounds an emotional alarm bell when we contemplate harming other people.  Second, this alarm system is 'myopic,' because it is blind to side effects. . . . These limitations make us emotionally blind--but not cognitively blind--to certain kinds of harm" (224).

Our evolutionary ancestors had an enormous capacity for premeditated violence.  Hobbes was right that in the state of nature human beings were roughly equal in that any healthy adult could kill anyone else, even the strongest.  And Hobbes was also right that anyone who was violent would provoke retaliation from his victims or their relatives.  Therefore, there was a natural need for all to seek peace so that they could enjoy the benefits of living together in cooperative groups.  We can assume, Greene argues, that this would have created evolutionary pressures for the evolution of an emotional alarm system in the brain to inhibit premeditated acts of aggressive violence, which would be adaptive for both individuals and groups.

This emotional alarm system would require that we have the ability to mentally inspect our premeditated plans of action, Greene reasons, so that if we see our actions directly causing the killing of someone, this would trigger our emotional alarm bells.  But perhaps this system is so simple that it cannot keep track of multiple causal chains, so that it sees the primary causal chain but not any branching causal chain.  In the case of the Footbridge Case, we think about the personal force in pushing the fat man onto the tracks in front of the trolley, which sets off our emotional alarm bells.  But in the Switch Case, we think about diverting the trolley away from the five people on the tracks as our primary end, and we are rather blind emotionally to the secondary effect of killing the man on the side track, although we are cognitively aware of this.

If this is right, then the utilitarian is someone whose neural circuitry does not attach more emotional weight to the killing of someone as the primary effect of an action than to the killing of someone as the secondary effect of the action.  That's why the utilitarian, with the rule that five lives are worth more than one life, will both pull the switch and push the fat man to save five lives.

Greene's general conclusion about all this is that "our moral intuitions are generally sensible, but not infallible," and whenever those moral intuitions deviate from utilitarian reasoning, the intuitions are mistaken, and they must be overridden by deliberate reasoning that suppresses the moral emotions.

So would Greene push the fat man?  No!  Here's what he says:
"Now, you may be wondering--people often do--whether I'm really saying that it's right to push the man off the footbridge.  Here's what I'm saying: If you don't feel that it's wrong to push the man off the footbridge, there's something wrong with you.  I, too, feel that it's wrong, and I doubt that I could actually bring myself to push, and I'm glad that I'm like this.  What's more, in the real world, not pushing would almost certainly be the right decision.  But if someone with the best of intentions were to muster the will to push the man off the footbridge, knowing for sure that it would save five lives, and knowing for sure that there was no better alternative, I would approve of this action, although I might be suspicious of the person who chose to perform it" (251).
This is complicated.  First, Greene admits that it's not clear that pushing people off footbridges to save others is really going to promote the greater good in the long run, because such behavior is likely to have bad consequences.  Second, Greene warns that the sort of people who could push people off footbridges are suspicious characters.  And, finally, Greene assures us that he is not one of those suspicious characters, because he feels that it is wrong to push people off footbridges, and he is proud that he has such virtuous emotions.

In fact, Greene admits that he is a hypocrite, in that he professes to be a pure utilitarian, but he cannot live completely by utilitarian rules because he's a human being with human feelings (254-68).  So, for example, he knows that in buying expensive birthday presents for his children rather than spending more of his money to help starving children around the world, he is failing to maximize happiness impartially, because he is partial to his children.  But, after all, this is only human nature.

One might be reminded of Peter Singer's confession some years ago that he was spending too much money on the care of his mother with Alzheimer's disease.  By his utilitarian principles, this was immoral, because his mother was going to die soon, and if he had sent this money to Oxfam, it would have saved many lives and thus maximized global happiness.  Like Greene, he is a hypocrite.

Greene says that if he were God, he would replace the human species--or Homo justlikeus--with Homo utilitus: "The members of this species value the happiness of all members equally.  This species is as happy as it could possibly be, because its members care about one another as much as they care about themselves.  This species is infused with a spirit of universal love.  That is, the members of this species love one another with the same passionate intensity that members of Homo justlikeus love their family members and close friends.  Consequently, they're a very happy lot" (267).

So pure utilitarianism is literally inhuman, because it contradicts our evolved human nature.  Purely utilitarian animals would have to belong to a different kind of species.

But then one might wonder whether even Homo utilitus would be truly utilitarian.  After all, the "spirit of universal love" in Homo utilitus does not seem to be truly universal, because it's restricted to members of that species.  Isn't this what Singer calls "speciesism"?  Doesn't utilitarian impartiality require universal love for all sentient beings--all beings capable of the experience of happiness--and not just members of our own species?

Doesn't this show how pure utilitarianism becomes incoherent?  In Greene's case, this incoherence comes from his religious longing for transcendence that conflicts with his scientific naturalism.  He repeatedly makes a "case for transcendence" (15-16, 25-27, 55, 63, 102, 200, 204, 264-67, 344-46, 349, 353), which culminates in his vision of himself as the Divine Creator who would replace the human species with Homo utilitus so that human beings could show universal love.  This is Gnosticism--the idea that we were created by an evil God who designed us so that we would be imprisoned in bodies with evil desires, and that our salvation requires a transcendence of our human nature through an enlightenment that transports us to a new realm of perfect universal love.

Thursday, September 04, 2014

The Scientific Study of Moral Emotion and Moral Reason in the Brain: Joshua Greene's Dual Process Theory

For thousands of years, political philosophers have debated the role of emotion and reason in moral judgment.  We can now study this question scientifically through evolutionary theory and neuroscience.  If the brain is a product of Darwinian evolution, then we can explain how the brain supports moral judgment as shaped by evolutionary selection.  We can also study the activity of the brain as engaged in moral judgments to identify the interaction between the more rational capacities and the more emotional capacities.  One way to do this is to use functional MRI brain scanning while people are thinking about moral dilemmas presented to them.  Some of this research uses the trolley problems developed by philosophers as thought experiments in experimental neuroscientific studies.  For me, this shows how we can turn political philosophy into an empirical science.  So, for example, I think we can see much of this scientific research as supporting the moral psychology of David Hume and Adam Smith.

One of the leaders in this research is Joshua Greene, who directs the Moral Cognition Lab at Harvard, and who has recently published a book surveying his work--Moral Tribes: Emotion, Reason, and the Gap Between Us and Them (Penguin Press, 2013).  In explaining moral philosophy as rooted in an evolutionary moral psychology, Greene shares a lot in common with Jonathan Haidt, who has been the subject of previous posts here and here.  But they disagree about exactly how emotion and reason are related in moral experience.  Haidt thinks Hume was right about reason being the slave of the passions.  As Haidt suggested in the title of one of his articles, the emotional dog wags his rational tail.  On the contrary, Greene argues, our capacity for rational deliberation can sometimes set aside what our moral emotions tell us, and this capacity for reasoning can lead us to embrace the principles of utilitarianism as the best moral philosophy, even though utilitarian thinking sometimes requires the denial of our emotional moral intuitions.  He believes that we can see this in the responses of the brain to trolley problems--and particularly in comparing our responses to the Switch Case and the Footbridge Case.

I agree that Greene's research illuminates the evolutionary and neural grounds of moral psychology.  But his argument for utilitarianism (of the sort developed by Peter Singer) seems incoherent to me.  I agree that we are partial utilitarians, because we all want to be happy, and we don't want to be miserable.  But we are not pure utilitarians of the Singer kind, because while we care for the happiness of all human beings to some degree, we care more for the happiness of ourselves and those close to us.  Pure utilitarianism in which we would maximize happiness impartially, so that no one's happiness would be any more important than anyone else's, is inhuman in its denial of our evolved human nature.  Oddly, Greene admits this when he says that utilitarians must be hypocrites, because their human nature forces them to love themselves and love their own more than strangers.  That's what I mean by incoherence.

I also disagree with Greene's claim that his research supports left liberalism as the best way to overcome the conflicts between moral tribes.  As he himself admits, libertarians are "the least tribal people of all" (341).  But he fails to see how the libertarian appeal to the individual liberty to pursue one's happiness provides the broadest foundation for moral tribes to live together in peace.  I have made a similar argument in my posts on Haidt.

I'll elaborate these points in subsequent posts.

Sunday, August 24, 2014

Trolleyology and Rawlsian Moral Grammar

 
                                                               Trolley Problem 1: Spur

 
                                                          Trolley Problem 2:  Footbridge


You are walking along the tracks of a trolley in San Francisco.  You notice that there is a runaway trolley that will kill five people who have become somehow bound to the tracks.  You also notice that there is a switch that will turn the trolley onto a side track, a spur, and thus save the lives of the five people.  Unfortunately, however, there is one person bound to the side track, and so if you throw the switch, he will be killed.  Should you throw the switch?

On another day, you are walking on a footbridge over the tracks.  You see another runaway trolley speeding toward five people bound to the track.  This time, there is no possibility of switching the trolley to a side track.  You could jump onto the track to try to stop it, but you are such a small person that you probably could not stop the trolley.  You notice that there's a big fat man on the bridge who is big enough to stop the train if you push him onto the track.  Should you push the fat man?

These stories might seem too cartoonish to be taken seriously as moral dilemmas.  But in recent decades, ever since they were first proposed by philosophers Philippa Foot and Judith Jarvis Thomson, they have become some of the most debated thought experiments among moral philosophers.  They have also been introduced into scientific experimentation conducted by philosophers, psychologists, and neuroscientists to test whether our moral intuitions about the trolley problem manifest an innate and universal moral sense shaped by human evolution and written into the neural circuitry of the brain.  This shows how a fundamental question in moral and political philosophy can be translated into experimentally testable propositions.  This trolleyology (as it has been called) has become a crucial part of the recent movement towards "experimental philosophy."

An engaging survey of this research has recently been published--Would You Kill the Fat Man? by David Edmonds (Princeton University Press, 2014).  The book elaborates an article by Edmonds that is available online.  A book by John Mikhail--Elements of Moral Cognition: Rawls' Linguistic Analogy and the Cognitive Science of Moral and Legal Judgment (Cambridge University Press, 2011)--shows how this research might confirm Rawls's account of moral knowledge as an innate moral sense analogous to what Noam Chomsky in linguistics has identified as the Universal Grammar that is innate in the minds of all normal human beings and allows them to learn any language.  This research has provoked a lot of criticism.  One of the most interesting lines of criticism comes from the Kantian utilitarian Peter Singer--in "Ethics and Intuitions," The Journal of Ethics 9 (2005): 331-52, which is available online.

Of the hundreds of thousands of people all around the world who have participated in formal trolley problem surveys, most people (up to 90% in some studies) would divert the trolley in the Spur case, but they would not push the fat man in the Footbridge case.  What is most striking about this is that most people react differently to the two cases although pulling the switch and pushing the fat man have identical consequences--one person dies to save five.

Joshua Greene and his colleagues have used brain scanning (functional magnetic resonance imaging) to study the brains of people as they think about trolley problems.  He found that there was a kind of neural wrestling between the calculating and emotional parts of the brain.  Responding to the Spur problem, most people decide to pull the switch, and the more calculating areas of the brain are active (the dorsolateral prefrontal cortex and the inferior parietal lobe), suggesting that they are calculating costs and benefits.  But in response to the Footbridge problem, most people decide that they cannot push the fat man, and the more emotional areas of the brain are active (amygdala, posterior cingulate cortex, and medial prefrontal cortex), suggesting that the idea of pushing the fat man is triggering emotional alarms.  For centuries, moral philosophers have argued about the relationship between moral reason and moral emotion in moral judgments.  Now, it seems, we can see that complex interaction between reason and emotion in the human brain.

For a Kantian utilitarian like Singer, the relevant moral principle in the trolley problem--that five deaths are worse than one death--is the same in both cases, and therefore Singer would pull the switch and push the fat man.  For Singer, the 10% of the people who would push the fat man are rightly following pure moral reason, while the other 90% are allowing their emotions to override their reason, because from the viewpoint of pure reason, there is no morally relevant difference between the two cases. 

Singer concedes that the reluctance to push the fat man probably shows a naturally evolved emotional predisposition against intentionally and directly killing an innocent person, even when such killing will save more lives.  But for Singer that only shows that moral reason should overcome the irrationality of our evolved psychology.  The fact that most people would not push the fat man is irrelevant to the normative question of what they ought to do.  Unlike the empirical sciences (such as the evolutionary science and neuroscience of human nature), normative moral and political philosophy belongs to a realm of pure reason that transcends the natural world of observable experience.  For these reasons, Singer rejects Rawls's claim that moral theory must be rooted in a moral psychology of moral intuitions.

In Section 9 ("Some Remarks About Moral Theory")  of A Theory of Justice, Rawls compared moral theory to Chomsky's linguistic theory that acquiring language depends on a Universal Grammar innate in all human beings.  Just as there might be an innate "sense of grammaticalness" that makes language possible, Rawls suggested, there might be an innate "sense of justice" that makes the practice and theory of justice possible (46-47).  And just as scientific linguists like Chomsky judge the truth of their linguistic theories by how well they explain the data of our linguistic practices, likewise moral philosophers can judge the truth of their moral theories by how well they explain the data of our moral judgments.  We must strive for "reflective equilibrium," Rawls argues, in which our general principles and our individual judgments about particular cases are in harmony.  We might have to revise our principles or revise our judgments until we reach some coherence between them, just as scientists revise their theories or reconsider their data until they reach sufficient harmony between theory and data.

Mikhail argues that Rawls was right to assert that moral theory can be rightly modeled on aspects of Chomsky's theory of Universal Grammar, and that the experimental study of how people solve trolley problems can uncover the Universal Moral Grammar that is innate in the minds of all normal human beings.  Just as there are some general principles of grammar innate in the minds of all normal language users making linguistic judgments, there are some general principles of justice innate in the minds of all normal moral agents making moral judgments.

Rawls argues that this moral grammar supports "justice as fairness" as grounded on the two principles of justice, including the difference principle.  Mikhail, however, is completely silent about these Rawlsian principles; and in place of these principles, Mikhail substitutes the legal norms of homicide and battery as manifested in the trolley problems and in legal tradition.

The trolley problems involve both homicide (the killing of one person to save five people) and battery (the pushing of the fat man).  Mikhail claims that the general principle that accounts for how most people solve the trolley problems is the principle of double effect as stated by Thomas Aquinas.  While the killing of innocent people is generally prohibited, killing can be permissible if the deaths are foresee but not directly intended and if there are good effects from this that outweigh the bad effects.  So, for example, if I kill in self-defense or in defense of the lives of others, and if the death of the victim is only a side-effect of my actions rather than a directly intended end, then the killing might be permissible.  Mikhail generalizes this principle to cover homicide and battery: "the principle holds that an otherwise prohibited action, such as battery or homicide, which has both good and bad effects may be permissible if the prohibited act itself is not directly intended, the good but not the bad effects are directly intended, the good effects outweigh the bad effects, and no morally preferable alternative is available" (149).  To apply this principle, we need to distinguish means, ends, and side-effects.

This allows Mikhail to explain the morally relevant distinction between the Spur case and the Footbridge case.  In the Spur case, the bystander creates a bad effect (the killing of the man on the spur) only as a side effect.  We know this, because we assume that if the man on the spur were able to free himself before he was hit by train, the bystander would prefer this.  The bystander directly intends to save the five people, but he does not directly intend to kill the man on the spur, although this is a foreseeable consequence.  The bystander must also assume that the bad effect of killing the man is outweighed by saving the five, and that there is no morally preferable alternative (such as throwing some object on the tracks to stop the trolley).

By contrast, Mikhail notes, if we suspected that the bystander was looking for a chance to murder the man on the spur, and so he used the runaway train as an excuse for switching the train towards his intended victim, then this might be considered intentional homicide.

The Footbridge case differs from the Spur case in one respect.  The bystander's pushing of the fat man is a directly intended battery and not just a foreseeable side effect, which most people judge to be forbidden.

But what should we say to Singer's objection to all this, which Mikhail calls "the objection from insufficient normativity" (188)?  The descriptive adequacy of Mikhail's account of how people respond to trolley problems says nothing, Singer complains, about the normative adequacy of our principles in deciding how people ought to respond to trolley problems.  Justifying moral principles is not the same as describing moral intuitions.  Normative moral theory is looking for universal and eternal principles of what is morally right or wrong that are true independently of what human individuals or human cultures believe to be right or wrong.  When Rawls appeals to the moral intuitions that are common among people who live in liberal democratic societies, Singer observes, he becomes a cultural relativist, so that liberal principles of justice are regarded as true only because they happen to be accepted in liberal cultures.  When Rawls suggests that there might be a universal moral sense that is expressed in liberal moral intuitions, and when Mikhail provides empirical evidence for this, this might escape the charge of cultural relativism; but this universal moral sense as imprinted in human psychology by human evolution is still only subjective, lacking in any objective truth, because it's a psychological projection of the evolved human mind rather than an objective truth about the universe.

Mikhail's response to Singer's objection is to admit that, yes, the moral grammar of human nature as a product of evolutionary history imprinted on the human brain is a projection of human psychology that has no mind-independent reality outside of the human mind.  If human beings did not exist as the kind of moral animals that they are, then their human morality would not exist.  Thus, there is no sharp distinction between the normative and the empirical, because normative morality is a projection of our empirical psychology.

The evolved rules of morality are more like the rules of baseball than the laws of physics:  the rules of baseball must be created by human beings, but the laws of physics exist independently of human beings.

What alternative is there?  Singer says that we need a cosmic morality--eternal and universal principles of right and wrong that are somehow woven into the frame of the universe and discoverable by human reason just as we discover principles of mathematics as somehow inherent in the structure of the cosmos.  But Singer never gives a clear explanation or proof of how this could be the case.  Notice that in his essay on "Ethics and Intuitions," he says that we need to prove the objective truth of morality as based on "pure reason" without intuition or emotion, but he indicates that no philosopher has ever successfully done this, and he will not do it himself.

In fact, as I have indicated in a previous post, Singer now admits that after many years of trying to prove that morality can be objectively true and rationally based, without any necessary foundation in evolved human psychology, he has failed, and so he doubts his previous arguments for a Kantian utilitarianism.  But, amazingly, after making this admission, he reaffirms "the existence of objective moral truths."  Although his Platonic longing for an eternal Idea of the Good has been frustrated, he still cannot give it up.

I say--better to be a satisfied Darwinian than a dissatisfied Platonist.

Some of these points are elaborated in other posts here, here, and here.

Wednesday, August 20, 2014

Experimental Testing of the Rawlsian Difference Principle

I have often argued on this blog that political philosophy is ultimately an empirical science that makes falsifiable claims about human nature and human history.  In arguing for Darwinian natural right, I am making falsifiable claims about Darwinian moral psychology that can be tested.

One can see this empirical falsifiability of political philosophy in John Rawls's Theory of Justice.  He makes a general claim that our capacity for justice requires a natural sense of justice or moral nature, which is comparable to what Noam Chomsky has identified in linguistics as the instinctive universal grammar that makes the acquisition of language possible (46-53).  He also makes a specific claim that under the conditions of the "original position" that are designed to ensure impartiality, human beings would unanimously choose certain principles of justice, including the "difference principle" that social and economic inequalities are justified only when they maximize the benefits for those who are worst off (60, 302). 

There is, I believe, some empirical evidence supporting Rawls's general claim for an evolved innate moral grammar or moral sense.  I will write about that in my next post.  His specific claim for the difference principle, however, has been empirically falsified.

Although it is impossible to replicate Rawls's original position completely, and thus it must remain a hypothetical thought experiment, it is possible to devise experimental conditions that approximate the original position.  Norman Frohlich, Joe Oppenheimer, and others have organized behavioral experiments in which people are put in conditions that approximate the procedures of the original condition.  Participants come together in small groups, and in choosing from a list of principles of justice for allocating resources in their group, they must reach unanimous agreement on their choice, without the participants knowing what their class position will be in that society.  They are then randomly assigned to high or low social positions, and they receive monetary payoffs based on the principle they have chosen.  Experiments of this sort have been conducted with university students in the United States, Canada, the Philippines, Japan, and communist Poland.

Remarkably, the outcome is uniform across all of these cultures.  Rawls's difference principle is almost never chosen.  By far the most common choice (in over three-fourths of the cases) is a floor constraint without a ceiling--that is, there is a minimum income guaranteed for the worst off, but there is no limit on the income that can be earned by the richest.  The next most common choice (in about 12% of the cases) is the principle of maximum income (no floor, no ceiling).  The third most common choice (in about 8% of the cases) is the principle of a range constraint--there could be economic inequality, but the gap between the richest and the poorest would be limited.  The difference principle--that no person's income can go up unless it increases the income of the people at the bottom--was chosen in only 1% of the cases, and they were all in communist Poland.

When participants are asked to explain their choices, they indicate that are trying to balance three distinct ethical claims--need, just deserts, and efficiency.  They think it's fair that those who are least well-off should have their minimal needs secured.  But they also think that those who earn higher incomes deserve this reward.  And they think that higher incomes for those who succeed is economically efficient in providing incentives for productivity that benefits everyone.

The most commonly chosen principle--floor constraint without a ceiling--looks a lot like what Friedrich von Hayek proposes in Part Three of The Constitution of Liberty: a largely free market economy combined with a welfare state that provides a minimal standard of security for all.

This seems to weaken Thomas Piketty's appeal to the Rawlsian difference principle as justifying confiscatory tax rates on high incomes and wealth for the sake of reducing inequality.

Remarkably, towards the end of his life, Rawls conceded what Frohlich and Oppenheimer had revealed in their experiments--that in circumstances of impartiality approximating the Rawlsian original condition, reasonable people would not all choose the difference principle but would rather choose the principle of a floor constraint without a ceiling.  In 1995, in his introduction to the paperback edition of Political Liberalism, Rawls admitted that while he still thought that "justice as fairness"--with its two principles of justice, including the difference principle--was the most reasonable conception of liberalism, there were other reasonable conceptions of liberal justice, including, for example, "one that substitutes for the difference principle, a principle to improve social well-being subject to a constraint guaranteeing for everyone a sufficient level of adequate all-purpose means" (xlvii).


REFERENCES

Frohlich, Norman, Joe A. Oppenheimer, and Cheryl Eavey, "Laboratory Results on Rawls's Distributive Justice," British Journal of Political Science 7 (1987): 1-21.

Frohlich, Norman, and Joe A. Oppenheimer, Choosing Justice: An Experimental Approach to Ethical Theory (Berkeley: University of California Press, 1992).

Lissowski, Grzegorz, Tadeusz Tyszka, and Wlodzimierz Okrasa, "Principles of Distributive Justice Experiements in Poland and America," Journal of Conflict Resolution 35 (1991): 98-119.

Rawls, John, Political Liberalism, expanded edition (New York: Columbia University Press, 2005).