A Liberal Realist Answer to Debunking Skepticism: The Empirical Case for Realism Abstract: Debunking skeptics claim that our moral beliefs are formed by processes unsuited to identifying objective facts, such as emotions inculcated by our genes and culture; therefore, they say, even if there are objective moral facts, we probably don't know them. I argue that the debunking skeptics cannot explain the pervasive trend toward liberalization of values over human history, and that the best explanation is the realist's: humanity is becoming increasingly liberal because liberalism is the objectively correct moral stance. 1. Debunking Arguments for Moral Anti-Realism 1.1. Three Skeptical Accounts of Moral Belief Can we ever know what is objectively right or wrong, good or bad? Moral realists answer yes. Anti-realists answer no: they believe that either there are no objective moral truths, or we have no knowledge of these truths. Anti-realists have often defended their position by appealing to one or another debunking explanation for moral beliefs. According to debunking explanations, our moral beliefs are chiefly or entirely produced by psychological mechanisms that are not suited to arriving at objective truths; hence, even if such truths exist, we probably don't know them. In principle, indefinitely many kinds of debunking theories are possible. For instance, if it turned out that your moral beliefs were implanted in your mind by a capricious hypnotist, those beliefs would thereby be 'debunked'. In practice, however, the debunking explanations seriously advanced have generally been of just three sorts. First, some hold that the moral beliefs of an individual are entirely a function of that individual's particular emotions and desires, understood as purely non-cognitive states. Thus, David Hume states that "morality is determined by sentiment" and that "to have the sense of virtue, is nothing but to feel a satisfaction of a particular kind from the contemplation of a character."1 Second, some say that our moral beliefs are chiefly or entirely the product of our particular culture. For example, those raised in strongly Christian or Islamic communities today often judge homosexuality to be morally wrong. But if they had been born in ancient Greece, they would more likely have accepted homosexuality.2 Furthermore, many theorists deny that our culture reflects any objective evaluative facts; it is just the set of practices that we happen to have adopted, no better or worse, objectively speaking, than any other set of practices.3 Third, in recent years, evolutionary explanations of moral attitudes have grown in popularity. For example, on the assumption that our genes influence our moral beliefs4 (perhaps indirectly, perhaps through our emotions), we can understand why most Hume 1975, p. 289; 1992, p. 471, emphasis in original.1 See for example, Plato 1977.2 Benedict 1934.3 Dawkins 1989, ch. 12; Wright 1995, ch. 10; Ruse 1998, pp. 218–22.4 1 people believe in a strong moral obligation to care for one's own children, but no parallel obligation to care for unrelated persons: in our evolutionary past, ancestors who accepted such an obligation tended to leave behind more surviving offspring than those who denied any such obligation. Enthusiasts for evolutionary psychology claim that there are many other cases in which common moral attitudes are most naturally explained by natural selection. Perhaps the most plausible debunking theory is a combination of the above three accounts: perhaps moral judgments are caused by emotions, desires, or other noncognitive states, and these non-cognitive states, in turn, are products of both genes and culture. Some recent work in psychology has lent credibility to this hypothesis. Psychologist Jonathan Haidt has done research suggesting that moral judgments are largely a product of gut reactions and that moral reasoning often functions merely as post-hoc rationalization. The dramatic differences in moral beliefs across societies5 surely lend credence to the claim that moral beliefs are largely caused by one's culture. That there is also a large genetic component is at least suggested by the recent research finding that the heritability of political orientation is approximately 0.53.6 1.2. Why the Debunking Theories Engender Skepticism Debunking accounts of moral belief could not show that there are no objective moral facts. What they might show, however, is that if there are objective moral facts, our belief-forming mechanisms are ill-suited to identifying them. Suppose that our moral beliefs are solely or chiefly produced by emotions. Emotions are typically not reliable guides to objective facts. Given the plausible assumption that knowledge requires a reliable belief-forming mechanism, this supposition would tend to suggest that our moral beliefs do not constitute knowledge of any objective facts; hence, that either there aren't objective moral facts, or there are but we don't know them.7 But suppose one thought that emotions, or at least some emotions, are actually evaluative representations. For example, perhaps to feel anger is, among other things,8 to feel that an injustice has been done. (This view differs from Hume's in the order of explanation: this view explains the nature of emotions in part by reference to moral propositions, whereas Hume proposes to explain moral "propositions" by reference to emotions.) On this view, it would not be strange that emotions should be reliable guides Haidt 2001.5 Alford, Funk, and Hibbing 2005, p. 162. "Political orientation" refers to a composite of6 responses to questions about various political controversies. The data show that genetically identical twins are much more similar in political orientation than are fraternal twins raised in the same home. Because political beliefs are strongly dependent on moral beliefs (Graham, Haidt, and Nosek 2009), this suggests that moral beliefs too have a substantial genetic influence. Does this argument require a process reliabilist analysis of knowledge? No, because the7 argument only assumes that reliability is one necessary condition for knowledge. This is compatible with, e.g., a defeasibility account of knowledge, where the unreliability of a beliefforming process counts as a defeater (for exposition of the defeasibility account, see Klein 1971). A related view is that desires are evaluative representations; see Oddie 2005. The same8 points apply to this view as to the view about emotions. 2 to evaluative facts even though they are poor guides to non-evaluative facts. For this reason, it will not suffice merely to observe that emotions are typically (in descriptive matters) poor guides to objective facts. We must rather consider the causes of our relevant emotions (the emotions that are plausible sources of moral beliefs) and ask whether these causes make it plausible to hold the resulting emotions to be reliable guides to the objective evaluative facts, if such facts exist. Thus, proponents of the first kind of debunking explanation for morality are naturally driven to elaborate their theory by appeal to one or both of the other debunking explanations: perhaps our moral emotions are caused by our culture or our genes. If so, there is no good reason to suppose that our moral beliefs will reflect the objective moral facts, even if such facts exist. Begin with the case of culture: there is so much variation in moral beliefs across cultures that culture, in general, cannot be a reliable guide to objective moral truths. Furthermore, there is no independent reason to think that our culture in particular should have the correct moral beliefs. Here, by "independent," I mean independent of our moral beliefs – of course, if one assumes the general correctness of one's current moral beliefs, one can go on to argue that one's own culture is peculiarly attuned to moral reality; but to the extent that one's moral beliefs are the product of that culture, this sort of bootstrapping reasoning seems illegitimate. Consider next the case of beliefs explained by natural selection. What nature selects for is reproductive success. If correctly identifying the objective moral truths does not contribute to reproductive success, then there is no reason why evolutionary processes should have endowed us with the capacity to identify those truths. And there seems to be no reason independent of our current moral beliefs to suppose that knowing the objective moral facts would have contributed to reproductive success. Indeed, because moral properties seem to have no causal impact on the physical world, it is hard to see how moral reliability could impact reproductive success.9 The debunking explanations for morality thus engender skepticism as to the reliability of our moral belief-forming mechanisms, on the assumption that there are objective moral facts. This in turn leads us to doubt that our moral beliefs could constitute knowledge of objective facts. 2. A Modest Liberal Realism 2.1. Three Realist Accounts of the Source of Morality Most moral realists would dispute the anti-realists' characterization of the source of moral beliefs. The realist need not, and of course should not, maintain that no moral beliefs are caused by emotions, culture, or genes. We need not make that claim, since realism is not the view that all moral beliefs constitute knowledge of objective facts; realism holds only that some moral beliefs constitute knowledge of objective facts. Therefore, it need only be held that some moral beliefs derive from reliable beliefforming mechanisms. Realists have advanced at least three accounts of the nature of these reliable mechanisms. First, some have held that we have empirical knowledge of moral facts, Street 2006, pp. 129-31. For a reply to this sort of argument, see Huemer 2005, pp. 218-19.9 3 through observation or inference to the best explanation. Second, some have held that10 there is a dedicated moral sense, that is, a faculty that functions specifically to cognize moral facts (or evaluative facts more generally) and nothing else. I shall not discuss11 these first two views further, however, because I find them improbable. The third account, by far the dominant one among intuitionists over the last century, is a rationalistic intuitionism. This account holds that our moral knowledge is of12 a kind with our other a priori knowledge, such as our knowledge of mathematics and of necessary truths of metaphysics. Obviously, the nature of this other a priori knowledge is a matter of controversy. Fortunately, we need not settle that controversy here. Rationalist intuitionism simply needs the assumption that there is some substantive, a priori (non-evaluative) knowledge. Knowledge requires a reliable belief-forming mechanism (that was a presupposition of the debunking arguments of section 1), so there must be a reliable mechanism that produces these non-evaluative a priori beliefs. Whatever that mechanism is, the rationalist intuitionist maintains, that mechanism is also capable of producing some moral beliefs. This is why it is plausible to think that some moral beliefs might be sufficiently reliable to qualify as knowledge. There are some who deny the existence of a priori knowledge altogether. Others13 admit only analytic a priori knowledge, which is supposed to be explicable purely in terms of one's understanding of the meanings of words. This would make rationalistic14 intuitionism very implausible. I think, however, that these views have been refuted elsewhere. Here, I shall simply assume that these empiricist views are wrong. The aim15 of this paper is not to debate rationalism versus empiricism. Rather, the target of this paper is the theorist who thinks there is something specially problematic about objective moral knowledge, such that, even if synthetic a priori knowledge in general is possible, our knowledge of morality would not be an example thereof. This is precisely the sort of position supported by the debunking arguments discussed in section 1. Those arguments do not appeal to some general empiricist doctrine; rather, they purport to show something specifically about how moral beliefs are formed, something that would not apply to other allegedly a priori beliefs (mathematical beliefs, for example, are not usefully explained by emotion, culture, or genes). 2.2. Liberal Realism I am not only a realist but a liberal realist: I think that the objectively correct values are liberal values. When I speak of liberalism, I intend, not any precise ethical theory, but rather a certain very broad ethical orientation. Liberalism (i) recognizes the moral equality of persons, (ii) promotes respect for the dignity of the individual, and (iii) opposes gratuitous coercion and violence. So understood, nearly every ethicist today is a liberal. But while this broad orientation is mostly uncontroversial today, this does not On moral perception, see McGrath 2004; Moore 1992, p. 2517. On explanation, see10 Sturgeon 1985; Railton 1998. For objections to these views, see Huemer 2005, section 4.4. Reid 1983, pp. 319-23; Butler 1964. This view appears to be Street's (2006) main target,11 though she does not name it as such. Prichard 1957, pp. 7-8; Ross, 1988, pp. 29-30; Huemer 2005, pp. 99-102, 215-16.12 Quine 1951.13 Ayer 1952; Mackie 1977, pp. 38-40.14 Bealer 1992; BonJour 1998.15 4 render the category of liberalism uninteresting, for, as we shall see below, human history was in fact dominated by highly illiberal views. The three aspects of liberalism named above are not simply three unrelated moral commitments. They are not like, for example, the commitments of "schliberalism", which is the conjunctive ethical theory that (a) fetuses have rights, (b) pleasure is good, and (c) breaking promises is permissible. Schliberalism is just a concatenation of unrelated views. By contrast, liberalism is a coherent ethical perspective. The idea that individuals should be treated with dignity fits together with the idea that individuals are moral equals, and that one should eschew violence and coercion against the individual. This point is of some import, since it helps to explain why it is a priori plausible to think that, if there are objective values, liberalism might be the objectively correct ethical orientation. This is not to deny that there might be other reasonable candidates for correct ethical orientations; it is only to say that liberalism ought to be counted high on the list of initially plausible candidates. 2.3. Modest Realism There are more and less extreme forms of realism. My realist view is relatively modest, in at least three respects. First, I do not hold that all or most moral beliefs constitute knowledge; indeed, it may be that only a small minority of moral beliefs constitute genuine knowledge of the objective moral facts. Second, though I deny that culture and genes provide a complete explanation for our moral beliefs, I do not doubt that culture and genes play an important role in explaining moral beliefs. Even if we have rational, ethical intuitions that are sometimes reliable, these intuitions are not anything close to the whole explanation for our moral beliefs. Third, though I insist that moral knowledge is possible, I do not claim that it is easy. Some moral knowledge might require careful reflection and skill in judgment. Some might emerge from a long and difficult process. Our society may need to accumulate its moral wisdom over a period of centuries, and a great deal of moral knowledge may yet elude us. All of this is compatible with the claim that moral knowledge rests ultimately on intuition. 3. The Phenomenon of Moral Progress I shall contend that certain empirical facts are difficult to explain on any of the debunking theories mentioned in section 1, and that by contrast, the modest, liberal realist can offer a plausible account of the data. Roughly, the data in question concern the development of moral values over the course of human history. 3.1. War and Murder In most societies throughout history, killing has been far more common than it is in our society today. The trend toward lower rates of violence is visible on the scale of decades, centuries, and millennia, it is consistent across countries, and it applies to both murder and warfare. These facts have been extensively documented elsewhere. Here, I will just16 Pinker 2011.16 5 mention one striking fact: in primitive societies, it is estimated that between ten and thirty percent of all deaths come at the hands of other humans, with most of these being deaths of men in war. Figure 1 shows estimates for the percentage of deaths due to war in seven contemporary primitive societies studied by anthropologists. Figure 2 shows17 estimated deaths due to war and murder in sixteen prehistoric primitive societies; these estimates are based upon sixteen archeological sites where human remains were found and examined for signs of death at the hands of other humans. In each figure, the18 death rate for Europe and the United States in the twentieth century is shown at the bottom for comparison. [ Insert Figure 1 ] [ Insert Figure 2 ] There are many factors that may have contributed to the decline in violence. But19 there is one that is of particular interest here: there has been a dramatic shift in human values over history. In primitive societies, including our own society in earlier20 centuries, physical combat was often regarded as glorious, honorable, and manly. Those who conquered others through violence were honored: Alexander "the Great" was so called because of his successful campaigns of violence in Asia and Northeast Africa. Likewise, Peter "the Great" earned his honorific through his successful attacks on other European nations. Today, such leaders would more likely be reviled as criminal aggressors. Consider these sentiments from prominent thinkers of the past:21 You say it is the good cause that hallows even war? I say to you: it is the good war that hallows every cause. (Friedrich Nietzsche, 1885) If war made men brutal, at least it made them strong; it called out the qualities best fitted to survive in the struggle for existence. [...] War, with all its horrors, could purify as well as debase [....] (Henry Adams, 1891) Would not the end of war be the end of humanity? War is life itself. Nothing exists in nature, is born, grows or multiplies except by combat. (Emile Zola, 1959) Murder has shown a marked decline over the centuries. In Europe, the murder rate has declined from about 35 per 100,000 population per year in 1300 A.D. to about 3 per Keeley 1996, pp. 196.17 Bowles 2009, p. 1295; Keeley 1996, p. 197. The two "Central California" entries refer to18 distinct sites in central California. For discussion of a variety of possible factors, see Pinker 2011.19 For discussion, see Mueller 2004; Huemer 2013.20 Nietzsche 2003, part 1, section 10, p. 35 (originally published 1883-1885); Adams 1891,21 p. 277 (discussing the war of 1812 and explaining the advantages of war over embargo); Zola quoted in Joll and Martel 2007, p. 275. 6 100,000 today. Again, many factors may have contributed to the decline – among them22 the changing attitudes toward murder. Men of the past perceived many more things as reasons for killing. Consider that in 1804, former American Treasury Secretary23 Alexander Hamilton died in a duel with sitting Vice President Aaron Burr. The duel was fought to settle a dispute over some disparaging remarks Hamilton had allegedly made about Burr. Such behavior on the part of respected men would be unthinkable today.24 3.2. Torture and Execution Governments of the past executed citizens at the drop of a hat, and in quite gruesome ways at that. In the middle ages, capital offences included sodomy, gossip, stealing cabbages, picking up sticks on the Sabbath, talking back to one's parents, and of course witchcraft. Execution methods included burning at the stake, drawing and quartering,25 boiling, and sawing. The last of these methods is depicted in figure 3.26 [ Insert Figure 3 ] Torture was accepted as a method of investigation. For instance, a suspected witch might be tortured until she (i) confessed to witchcraft, and (ii) named the other witches that she presumably knew about. The other accused witches could then be tortured to verify their guilt. Here I shall forebear from describing the medieval torture techniques, as their mere contemplation is more than should be asked of a reader in a civilized society. The good news is that over the past four hundred years, torture has been abolished throughout Europe and most of the world. 3.3. Slavery Slavery has been accepted in many societies throughout human history and was often endorsed by the moral authorities of the day. Aristotle, considered by many the27 greatest philosopher of all time, saw no problem with waging war to capture slaves: But the art of acquiring slaves, I mean of justly acquiring them, differs both from the art of the master and the art of the slave, being a species of hunting or war.28 The Bible, long considered by many a font of moral wisdom, advised readers on just how severely one may beat one's slaves: Spierenburg 2008, pp. 3-4; United Nations Office on Drugs and Crime 2013.22 On the acceptance of killing in primitive societies, see Oesterdiekhoff 2011, pp. 169-70;23 on honor-motivated killings in medieval Europe, see Spierenburg 2008, pp. 7-8. Library of Congress 2011.24 Pinker 2011, p. 149.25 From a fifteenth century print, reproduced in Held 1987, p. 47.26 Bradley and Cartledge 2011; Eltis and Engerman 2011.27 Aristotle 1941, 1255b37-40.28 7 If a man beats his male or female slave with a rod and the slave dies as a direct result, he must be punished, but he is not to be punished if the slave gets up after a day or two, since the slave is his property.29 If such passages were written today, the author would have to be insane. Obviously, these passages came across very differently in the societies for which they were originally written. Over the past two hundred years, the world saw a wave of abolitions, with the result that today, slavery is illegal in every country in the world. Figure 4 shows when slavery was abolished in 49 selected countries.30 [ Insert Figure 4 ] 3.4. Racism and Sexism Contemporary political activists sometimes decry the racism and sexism of our society. But again, for anyone with broadly liberal values, a look at our past provokes first shock, then gratitude that we no longer live in such bigoted times. In earlier decades, even in democratic societies, women were literally prohibited from voting, due in part to their supposed inferiority. That situation started to change around 1920 (see figure 5).31 Though it remains true today that many desirable professions are disproportionately occupied by men, in earlier ages, women were completely barred from most professions. [ Insert Figure 5 ] Even after slavery was abolished, Americans continued for decades to impose policies that were severely and explicitly racist. Black citizens were expected to ride at the back of the bus, use separate drinking fountains and restrooms, and attend separate schools – all to prevent contamination of whites by blacks. These laws ended in the United States in the 1960's. Since that time, attitudes have shifted dramatically: if32 someone today were to advocate the sort of laws that actually existed fifty years ago, listeners would assume the speaker needed to have his head examined. If the advocate were a politician, his career would be instantly ended. 3.5. Democratization Throughout human history, the vast majority of governments have been dictatorial. In the year 1800, there were, by modern standards, no genuine democracies. Since then, democracy has spread to about half of all the world's countries and appears poised to Exodus 21: 20-21.29 Data source: Wikipedia 2014a.30 Data source: Wikipedia 2014b. Dates used are the first year women could vote in any31 election in a given country. For an account of the American civil rights movement, see Williams 1987.32 8 take over the globe (see figure 6). In about the last twenty years, democracy has spread33 to about as many countries as it had reached during the previous two hundred years. [ Insert Figure 6 ] 3.6. Decolonization Throughout most of human history, building an empire through conquering other peoples has been viewed as a great achievement for a leader. The twentieth century witnessed two of history's greatest empires: the British Empire and the French Empire. Both of these empires also collapsed in the last century, as nearly all the conquered peoples regained independence. In some cases, independence was gained through bloody warfare; in others, as in that of India, it was gained through non-violent protest movements.34 The latter phenomenon is striking. What if, during the reign of Alexander of Macedon, the Persians had sought independence through non-violent protests, using civil disobedience, general strikes, and so forth? Why didn't the people conquered by Genghis Khan think of holding sit-ins and protest marches? If there had been a Gandhi in the time of Khan, he would most likely have been swiftly executed by the conqueror whose moral legitimacy he'd sought to call into question. The British Empire collapsed not because the British lacked the power to defend it, but because – to a much greater degree than earlier conquerors – the British had a conscience. 3.7. Summary There has been enormous moral progress over human history. This progress is not just a matter of changing practices but of changing moral beliefs. Modern humans are far more liberal than those of earlier ages; mainstream illiberal views of earlier centuries are shocking and absurd to modern readers. The trend toward liberalization is consistent across many issues. War, murder, slavery, democracy, women's suffrage, racial segregation, torture, execution, colonization: on all these issues we have seen dramatic attitude shifts, all in the liberal direction. It is difficult to think of any issue on which attitudes have moved in the other direction. This trend has been ongoing for millennia, accelerating in the last two centuries, and even the last fifty years, and it affects virtually every country on Earth. That is a very striking empirical fact – indeed, it is among the most important trends in human history. How are we to explain all this? 4. The Failure of Debunking Accounts 4.1. A Darwinian Trilemma There is one trivial sense in which an evolutionary account of ethics must be correct: human beings evolved, and therefore, however our capacity for moral judgment works, Data source: Center for Systemic Peace 2011. I count as democracies all countries with33 scores of 6 or higher on the polity2 variable in the Polity IV dataset. Note that the dataset includes only countries with populations of at least 500,000, and data are sparse before 1900. For an account of the Indian independence movement, see Sarkar 1988.34 9 that capacity is a product of evolution, as are all of our capacities. This thesis of "an evolutionary origin for ethics" poses no threat to moral realism, because the thesis would be true regardless of whether our moral judgments were reliable indicators of moral truth, just as the analogous thesis is true of our judgments in all other areas. The kind of evolutionary thesis that is supposed to pose a problem for realism holds that our specific moral values are adaptations. For example, the tendency to judge that adultery is wrong might have been selected for because that moral judgment promoted reproductive fitness among our ancestors. This would cast doubt on the reliability of that moral judgment. Recall that realism is committed only to the view that some moral beliefs constitute knowledge, whereas anti-realists hold that no moral belief constitutes knowledge of an objective fact. Thus, to support anti-realism using a debunking account of moral beliefs, the anti-realist must hold that all moral beliefs either are adaptations, or have some other source that we should not expect to be reliably truth-directed. In particular, then, the anti-realist who pursues this strategy would have to give a debunking account of liberal moral beliefs, as well as of illiberal ones. Since we are here considering evolutionary debunking accounts, the question is now whether an evolutionary account of liberalism is plausible. In explaining the rise of liberalism, adaptationists face a trilemma: either (i) they hold that liberal values are adaptive, (ii) they hold that liberal values are not adaptive, or (iii) they hold that liberal values are adaptive in modern societies but were not adaptive in earlier times. On the first horn, the adaptationist might appear to be able to explain the current prevalence of liberal values. But they could not explain why liberal values are relatively recent, and why these values have been spreading and strengthening over human history. Human beings existed in primitive societies for hundreds of thousands of years before recorded history, and all of recorded history occupies only a few thousand years, which is a brief time in evolutionary terms. It therefore strains credibility that the adaptive set of values should have evolved during the brief period of recorded history, having failed to evolve during the preceding two hundred thousand years that humans existed or the millions of years during which our primate ancestors existed. On the second horn of the trilemma, the adaptationist can explain why most human beings throughout most of history have held illiberal values. This, however, poses no threat to the liberal realist; indeed, the liberal realist ought to enthusiastically embrace the evolutionary debunking of illiberal beliefs, since it lends support to the contention that modern, liberal values are more trustworthy than the values of the past. The adaptationist could not, however, explain modern, liberal values. Thus, the modest liberal realist's position would be undamaged, or indeed strengthened, by the putatively debunking skeptical argument. Only on the third horn could the adaptationist possibly account both for the illiberal beliefs of the past and the liberal beliefs of the present. Perhaps as conditions in society have changed, liberal values have become increasingly adaptive, thus leading to their spread across the world. This theory, however, is extremely implausible empirically. One problem is that the shift in values has been far too rapid to be explained by biological evolution. The Jim Crow laws in the United States were abolished only in the 1960's; before that, explicit racism was perfectly socially acceptable. It is not the case that there was a gene for racism that was selected out of the gene pool in the 1960's. 10 Another problem is that an adaptationist account of liberalization would have to work via the supposition that those with liberal values have in recent times had greater reproductive success than their ideological opponents. But there is no reason to believe this. There is no reason to think, for example, that in the 1960's racists started having fewer children than non-racists and thus failed to pass on their racist genes, or that during the last two hundred years, people who supported democracy started having more children than those who supported dictatorship. 4.2. Changes in Gene Expression For the reasons given, the idea of accounting for ethical liberalization through genetic change is unpromising. The same genes, however, can sometimes be expressed differently in different environments. Thus, there is a theoretical possibility that moral beliefs are adaptations, and yet that changes in prevailing moral beliefs could be brought about by environmental changes in the absence of genetic change. Here is one hypothesis: perhaps we have a gene (or set of genes) with both of the following properties: (i) it inclines one toward illiberal beliefs if resources are scarce and survival uncertain, but (ii) it inclines one toward liberal beliefs if one is well-off and secure. In that case, as a society advanced economically and its members became more prosperous and secure, the values of those members would become increasingly liberal. While this hypothesis is logically possible and would neatly solve the adaptationist's problem, there doesn't seem to be any reason to believe it (notice that whatever psychological changes we observed over history, one could always hypothesize that there is a gene that happens to cause each type of psychological trait, in the social circumstances in which it was in fact prevalent). To begin with, it is not clear, on a theoretical level, why such a gene or set of genes should have been selected; it is not clear why liberal values would promote reproductive success for a well-off and secure person, but not for one who is poor and insecure. In addition, in humanity's illiberal past, those who were wealthy and secure (aristocrats) were typically not at all liberal; they were the ones oppressing the rest of their societies. Here is another hypothesis: perhaps there is a gene that inclines one toward illiberal beliefs if one's society as a whole is primitive and poor, but inclines toward liberal beliefs if one's society is advanced and prosperous. This hypothesis, however, is even harder to motivate theoretically. Again, it is unclear why such a gene would be especially advantageous, as compared with a gene that causes one to be liberal in all conditions, or illiberal in all conditions. Even if such a gene would be advantageous, there has not been sufficient opportunity for it to be selected, since for almost all of the history of the species human beings have lived in poor, primitive societies. Humanity has not had enough experience with shifting between poor and prosperous, or primitive and advanced societies, for evolution to have designed special instructions governing what to do in an advanced, prosperous society. If evolution wholly controlled our moral values, the values it gave us would have been the ones that were adaptive in poor, primitive societies, and we would most likely continue using those same values when we reached the unprecedented situation of living in advanced, prosperous societies. 4.3. Debunking Cultural Accounts The proponent of cultural explanations for moral values would seem to be in a better 11 position to accommodate the phenomenon of moral liberalization. Culture, after all, is capable of changing much more rapidly than biology. And it is mainly a shift in culture that would explain why a given individual today is much more liberal than most people in the past. We do not all independently figure out that slavery is wrong as we grow up. We are taught that slavery is wrong; that is now part of our culture. But to say this really takes us almost no distance toward explaining the phenomenon that is of interest. The interesting question is, why has our culture evolved in the way that it has? Often, in explaining human behavior, culture is taken as given, with no further explanation needed. Perhaps cultures simply change over time in unpredictable ways, so that there is no point in asking for an explanation of why a culture incorporates certain values, or why it has changed in a certain way. But in the present case, this would be not only an unsatisfying but a deeply implausible attitude to adopt. The liberalization of human values over time does not look like a random process. It looks very nonrandom, for three reasons. First, the development with which we are concerned comprises a set of changes in attitudes on multiple different issues – slavery, war, torture, women's suffrage, and so on – that all fit together; all are consistent with a certain coherent ethical standpoint. Second, the change has been proceeding in the same direction for centuries. Third, the changes have affected nearly all societies across the globe. This is not a "random walk"; this calls out for an explanation. Perhaps we can provide piecemeal explanations for liberalization with respect to different issues and different countries. For example, why was slavery abolished in the United States? Abraham Lincoln prosecuted the American Civil War for the purpose of preserving the union. During the war, Lincoln issued the Emancipation Proclamation, freeing most of the slaves, as a measure to help the Union win the war: the Proclamation increased the morale of Union troops and induced some slaves in Confederate states to escape from their masters, which weakened the South. As the Union defeated the Confederacy, the Proclamation became enforceable. In some sense, this is a correct explanation for why most of the slaves in the U.S. were freed (the rest being freed later by the Thirteenth Amendment). But we should also find this unsatisfying, because slavery was not just abolished in the United States. Starting from a point when slavery was widely accepted, it came to be abolished in every country in the world over the past few centuries. Are we to believe it is coincidence that in all these countries some concatenation of events leading to abolition transpired, like those that occurred in the United States? Surely there is some further explanation; surely something could be said about why slavery in general was not a stable practice in modern times. Of course, there are other kinds of explanation for the abolition of slavery. For example, perhaps slavery was best suited to an older, more agriculturally centered economy but was ill-suited to modern, industrial economies. Thus, as industrialization spread across the globe, slavery became less advantageous, and perhaps this led to its abolition. This explanation is of course speculative. Moreover, it again requires that we accept a great coincidence. For it is not just that slavery was abolished. It is that liberalism triumphed on many different issues over the past few centuries. Are we to believe it is coincidence that, at the same time that slavery was becoming economically inefficient, some other trend was leading women's suffrage to become more popular (perhaps women's suffrage also becomes more economically advantageous in industrial 12 societies?), another trend was causing democracy to spread across the world, another was causing war to seem less glorious, another made torture seem less beneficial, and so on? Again, it is important to note that this is not just a series of unrelated changes; they are all changes in line with a certain coherent ethical perspective. It would be difficult to state how all these changes cohere without using moral or quasi-moral concepts: all the changes fit together, in one way or another, with the value of equal respect for the dignity of persons. I of course cannot anticipate every possible explanation for the shift in values over time. What I will do at this point, then, is simply to present my own realistic account, leaving it to the anti-realists attempt to devise a better explanation. 5. A Realist Account of Moral Progress Why was slavery abolished? Because slavery was unjust. Why has democracy spread to ever more countries over the past two centuries? Because democracy is better than other systems of government. Why have human beings become increasingly reluctant to go to war? Because war is horrible. Why has liberalism in general triumphed in human history? Because liberalism is correct. These, I suggest, are the most simple and natural explanations. But how could such explanations be correct? The explananda in these cases are partly social and psychological, and partly physical; for instance, the decline in the prevalence of war involves changes in the sorts of physical events that tend to happen to human bodies. But moral properties and relations – injustice, betterness, horribleness – have no causal powers, certainly not on the physical world. Therefore, they could not have any role in explaining any physical facts, could they? In the remainder of this35 section, I aim to explain both why these moral explanations are plausible and how they are possible. 5.1. The Pattern of Intellectual Progress in History Critics of moral realism have often appealed to the argument from cultural variation: it is said that the truth of moral realism predicts that there should be broad agreement on moral values across the world; since in fact there is a great deal of disagreement, this constitutes evidence against realism. The critics are partly right. If there were objective values, and humans had some way of accessing them, we would expect a certain amount of agreement. How much agreement should we expect, and what patterns should we expect to see in the points of agreement and disagreement? The most obvious way of addressing this question is to look at other areas of inquiry, such as mathematics, physics, cosmology, geology, psychology, and biology. These are all areas in which there are objective facts to which human beings have some (more or less imperfect) means of cognitive access. In these areas, we observe the following: First, we find no universal agreement across cultures. Rather, in primitive cultures, we find a wide variety of beliefs at variance with those of our own society. For example, in our society, the Earth is thought to have been formed as a result of gravitational Concerns of this sort are raised by Harman (1977, pp. 6-9) and Street (2006, pp. 129-31).35 13 accretion from a solar nebula. But according to an ancient Egyptian account, the Earth was the offspring of a mating between Sky and Moisture. In our society, it is thought36 that the continents were formed by plate tectonics. But according to the Iroquois of North America, the continents were formed as a result of a muskrat piling mud on the back of a turtle. Even our own society in earlier centuries had radically different views37 from those we hold today. Today, we believe that most diseases are caused by microscopic bacteria and viruses. But in the middle ages, it was thought that diseases were caused by imbalances of the four bodily humors, namely, black bile, yellow bile, blood, and phlegm. Today, it is thought that there are about a hundred elements,38 beginning with hydrogen, helium, lithium, and so on. But in ancient Greece, it was thought that there were four elements, and they were earth, air, fire, and water.39 Second, our beliefs have changed in certain ways over time. They have become more subtle, complex, and technical. This is illustrated by the above examples. This process is long and often arduous, but punctuated by occasional "scientific revolutions" in which opinions shift rapidly on a particular question. Third, different societies around the world tend to converge on certain accounts, once they are exposed to these theories and the evidence for them. No Egyptian today, for example, holds that the Earth was created by sexual reproduction between Sky and Moisture. Again, this convergence has been a gradual process which remains incomplete. For example, even in modern, Western societies, there remain lay people who believe that the Earth was created by Jehovah in the year 4004 B.C. What we can40 say, however, is that that view is on the wrong side of history. The view that the Earth was created 4.5 billion years ago by accretion from the solar nebula is the dominant theory, held by virtually all of our society's experts in the subject. And this is not specific to a particular society; thus, for example, astronomers in Japan, Egypt, France, and Venezuela can all agree on this. 5.2. The Pattern of Moral Progress What, then, about ethics? If ethics is a genuine field of objective knowledge, we should expect to find a similar pattern. And so we do: First, we should not expect cross-cultural agreement among primitive societies. Just as primitive cultures diverge (both from each other and from our own culture) in their descriptive beliefs about the world, we should not be surprised to learn that they diverge in their moral beliefs. Second, however, we should expect ethical beliefs to develop over time, to become more subtle, complex, and technical as societies advance. A perusal of the ethics literature bears this out. With all due respect to the great philosophers of the past, recent work by, say, Judith Thomson, is considerably more complex, more subtle, and more Lindberg 1992, p. 9.36 Duane 1998, p. 16.37 Lindberg 1992, pp. 116-17, 332-3.38 Lindberg 1992, pp. 31, 40.39 Newport 2012.40 14 technical than, say, Plato's discussion of the good.41 Third, we should expect convergence across societies over time – not immediately, but perhaps over the course of centuries or millennia. This expectation is borne out by the trends discussed in section 3 above: over the long term, societies across the world are converging on a liberal value system. Notice that this prediction is not tied to any specific theory of how moral knowledge is gained. Convergence is observed in a priori fields such as mathematics, in experimental sciences such as physics, and in (partly) historical sciences such as astronomy. As long as human beings possess some reliable belief-forming mechanism, whether the mechanism be a priori or empirical, it should be possible eventually to attain convergence on approximately true theories. Thus, if liberalism is the (approximate) moral truth, we should expect eventual convergence on liberal values. 5.3. Overcoming Cultural and Evolutionary Bias Some moral beliefs give the distinct appearance of culturally induced biases – for example, the idea that members of one's own social group are better or more important than those of other social groups; that it is good if one's own society conquers others, but bad if another society conquers one's own; or that those who disagree with one's own religious or cultural beliefs are corrupt and should be punished and forced to convert. And some moral beliefs give a distinct appearance of evolutionarily designed bias – for example, the idea that one's own offspring are more important than other people, the idea that sexual promiscuity is good for a male but bad for a female, and again the42 idea that killing others to seize their territory or resources is good. Liberal moral beliefs, however, do not belong to either class: they do not have the appearance, prima facie, of biases induced either by one's culture or by one's genes. In most cases, they have the opposite appearance of rejecting biases induced by culture or genes. Notably, the idea of the moral equality of all persons stands opposed to precisely those biases that human cultures have traditionally inculcated and that evolutionary psychology would lead us to expect. The prevalence of the idea that one's own social group is superior to others is perfectly understandable in terms of both cultural and biological evolution, as is the idea that violence is justified in the struggle for dominance. By contrast, the liberal rejection of those ideas looks like a product of rational reflection and an overcoming of the cultural and biological biases. Not all of our biases have as yet been overcome, but those that remain appear to be softening. Consider, for example, the idea that adultery – especially on the part of a woman – is a terrible crime. On a purely intellectual level, it is not obvious today what great harm is caused by consensual (on the part of the participants) sexual relations between a woman and a person who is not her husband. But in terms of evolutionary psychology, the feeling is easily explained: sexual infidelity creates a risk of causing the woman to become pregnant with the offspring of the partner who is not her husband, which in turn prevents the woman, for a certain time, from becoming pregnant with her husband's offspring. It may also result in the husband's devoting great resources to See for example, Thomson 1986. 41 For an evolutionary explanation, see Dawkins 1989, ch. 9.42 15 raising the other man's offspring, resources that could have been spent raising a child of his own. In evolutionary psychology, the key factor in explaining human attitudes toward any given event is how that event would have affected the individual's expected reproductive success, in the environment in which humans evolved. For the reasons just given, in the environment of our ancestors, which lacked effective contraceptives, sexual infidelity on the part of a woman would have caused a very large decline her husband's expected reproductive success. Thus, we can understand why a tendency to feel extremely negative reactions toward such infidelity would have had evolutionary survival value. This evolutionarily-induced sentiment remains with us to a certain degree today; as a result, adultery is still regarded as seriously wrong in our society. But consider the change over history: today, adultery is considered grounds for divorce; but in traditional Judeo-Christian and Islamic doctrine, adultery was considered grounds for execution.43 The change in attitudes here is another example of the liberalization of values. To the extent that evolutionary psychology explains the traditional hatred for adultery, the liberalization of attitudes about adultery suggests a move away from our biological programming. Or consider the idea that members of one's own social group are more important than others. Again, on a purely intellectual level, the idea is puzzling. But its prevalence can be understood in terms of cultural evolution: in human history, social groups that inculcated this value of in-group loyalty tended to promote their own survival and expansion at the expense of other groups that did not do so. Thus, we should find the value prevalent in surviving societies.44 This culturally-induced bias, too, remains with us to some degree today. But again, notice the change over time. Today, many believe that they should place the interests of their own compatriots ahead of the interests of foreigners – for instance, that one should rather give to charities helping the poor of one's own country than to those helping the world's poor. But in earlier centuries, people believed that violently attacking other countries to slaughter or enslave their people was a justified and – if successful – glorious practice. To the extent that cultural evolution explains the traditional suspicion of foreigners, the modern liberalization of attitudes toward foreigners represents a shift away from our earlier cultural biases. 5.4. How We Know Moral Truths In this section, I address an argument for moral skepticism. I begin in subsection 5.4.1 by setting out the skeptic's argument, which I will answer in subsections 5.4.2 and 5.4.3. 5.4.1. Skeptical Doubts About Cultural Beliefs Do we really know, for example, that slavery is wrong, or do we merely (correctly) believe that it is? For our belief to count as knowledge, it seems (and I shall grant the skeptic this premise), the belief must have been formed by a reliable process, one that systematically tends to lead to true beliefs. Most of us believe that slavery is wrong Leviticus 20:10; Quran 4:15; Sahih Bukhari 83:37.43 This of course is not the only explanation; a biological explanation is also possible.44 16 because that idea is part of our culture. If we had been born two hundred years ago in the American South, most of us would have believed that slavery was acceptable. It isn't that we reason from "my society disapproves of slavery" to "slavery is wrong." It is rather that our culture influences how things seem to us. If we'd lived in a slaverypracticing society, slavery just would have seemed a lot less bad to us. But that suggests that our belief-forming mechanism is unreliable. Perhaps appearances in general are usually reliable, but appearances that are heavily dependent on one's particular culture are not. If our belief-forming mechanism is "believe moral appearances caused by cultural conditioning," that mechanism would have led to proslavery beliefs in most societies throughout history, in addition to many other false beliefs. So, even if we are right in condemning slavery, it seems that we do not know that slavery is wrong. 5.4.2. How I Know Scientific Truths by Trusting My Culture Before directly addressing the moral skeptic's argument, it is worth considering the parallel reasoning as applied to certain non-evaluative beliefs. In any normal context, if someone asks me, "Do you know how old the Earth is?", the proper answer for me to give is "yes": I know that the Earth is about 4.5 billion years old. But I did not observe any of the physical evidence on which that estimate is based. Truth be told, I could not even tell you how the age of the Earth was calculated. I am relying on the testimony of my society's recognized experts. But in most places and times throughout history, such reliance would have led one to falsehoods more often than to truths. If my beliefforming mechanism is "Believe what the accepted experts in your society say," this mechanism would have led me, in earlier times, to think that the Earth was only a few thousand years old; that the material world was constituted by the four elements of earth, air, fire, and water; that diseases were caused by imbalances of the four bodily humors; and so on. If I'd been born in another society, it would have led me to think that the Earth was produced by a mating of Sky and Moisture. So, even if I am right in placing the Earth's age at 4.5 billion years, it seems that I do not actually know that this is the Earth's age, since my belief forming process is unreliable. This skeptical argument could be applied to most of my beliefs about the world (that is, my beliefs about the things outside of my range of experience). How should we respond to the argument? To begin with, I think we have to say: our culture is special. Granted, throughout history, many people have wrongly taken their own cultures to be special; it might nonetheless be true that some cultures are really special. What is special about our culture is that it possesses modern science, which is a reliable way of learning about the world. It was the methods of modern science that generated the "4.5 billion years" estimate for the Earth's age. This is utterly different from how the beliefs of other cultures were arrived at, such as the belief that Earth was produced by intercourse between Sky and Moisture. In assessing the reliability of my belief-forming mechanism, when my belief is formed as a result of the influence of my culture, should we take into account the reliability of the mechanism by which my culture arrived at its beliefs? I think the answer is yes. Here is the argument: intuitively, it is correct to say that I know how old the Earth is. But if the reliability of my belief-forming mechanism is assessed by reference to the reliability of cultural beliefs in general, then my belief about the age of the Earth would have to be judged as unreliably formed and therefore not a case of knowledge. 17 Therefore, it must be that the reliability of my belief-forming method is not to be assessed by reference to the reliability of cultural beliefs in general. There must be something that enables this belief to count as being formed by a more reliable method than the beliefs that make up the mythologies of other cultures. Presumably, that something has to do with the reliability of modern science. Perhaps, for example, my belief-forming method should be construed as something like "relying on accepted scientific beliefs, in a society that has an advanced scientific practice." There are of course other ways of characterizing the belief-forming process; the important point is that the reliability of modern science should be implicated in the account of why my belief-forming process is reliable in this case, even though I did not myself perform any scientific investigations, because (a certain subset of) my society did perform scientific investigations to arrive at the belief about the age of the Earth, which they in turn transmitted to me. 5.4.3. How I Know Moral Truths by Trusting My Culture Now return to the case of moral beliefs. Why does my belief in the wrongness of slavery count as a belief "formed by a reliable process"? What I want to say here is analogous to what I have suggested in regard to the belief about the age of the Earth. My intuition is influenced by my culture, but this does not disqualify it as a reliable source of moral guidance, because there was a reliable process by which my culture arrived at its current anti-slavery stance. Of course, the process by which our culture developed its liberal values is not the same as the process by which scientists arrived at their estimate of the Earth's age; liberalism did not triumph through scientific investigation. What matters is simply that there is some reliable process by which our values developed. To explain the nature of that process, I must first mention some background assumptions: a. First, I assume that human beings possess a general capacity for a priori knowledge, sometimes called "reason," "the understanding," or "the intellect." No very specific assumptions about this capacity are needed, beyond that it is capable of producing a priori knowledge. b. Ethics is among the subject matters to which that capacity can be applied. In other words, we can, at least sometimes, form a priori ethical beliefs through the same general mechanism by which we form other a priori beliefs. (a) and (b) are standard assumptions of rationalist intuitionism. Note that they have not been devised ad hoc to help in the explanation of liberal progress over human history. Rather, these assumptions have seemed plausible to many moral realists, from Plato to W. D. Ross. But while I endorse assumptions (a) and (b), I also think they provide a very incomplete picture of human moral thought. To better fill out the picture, we must include three more observations: c. Human beings also undergo non-rational influences on our moral belief-formation. Among these influences are emotions and desires, possibly including emotions and desires that are genetically programmed as a result of natural selection, and others that are explained by the cultural practices with which one was raised. None of these 18 factors strictly determines our moral beliefs, but each influences those beliefs. d. Because of the strong influence of culture, it is very difficult, and hence rare, for an individual to embrace a moral position that is radically at odds with the values of his own society, even if that proposition is objectively true. It is, however, much easier, and hence more common, for an individual to embrace a position that is slightly at variance with the values of his society. In other words, it is easier in thought to move a small distance from one's culture than to move a great distance. For example, a person who lived in medieval Europe, when gruesome execution methods were applied for a variety of (what we today would call) minor offenses, would have found it much easier to take seriously the proposition that execution should only be used as a punishment for egregious crimes, than to take seriously the proposition that no one should ever be executed. This would be the case even if the truth is that no one should ever be executed. e. Individuals differ in their moral sensitivity and in their susceptibility to non-rational influences on belief-formation. In other words, some people are more biased than others, and some people are better at apprehending moral truths than others. Again, none of these are ad hoc postulates; each is independently motivated. Assumptions (c) and (d) are independently supported by empirical evidence. Assumption (e) is a natural concomitant of moral realism: in every other area of cognitive performance, individuals show varying aptitudes. Some are better at mathematics than others; some are better at writing than others; some are better at remembering historical facts than others. If moral judgment is a form of cognition, then it would be amazing if some people were not better at moral judgment than others. It would likewise be extremely surprising if individuals did not differ in their susceptibility to various kinds of bias. Here is how the liberalization of values comes about. In primitive times, human beings begin with very badly misguided moral beliefs. This parallels the widespread and severe error that primitive societies begin with in all other areas of inquiry. In the case of morals in particular, we have non-rational emotions and desires influencing our beliefs and hence leading us astray – the very sort of influences that the debunking skeptics advert to in their effort to impugn all moral beliefs. Individual members of society will differ in their ability to notice these moral errors. At any given point in history, there will typically be some individuals who see some of the moral errors of their society. If, however, the prevailing norms are very far from the moral truth, then it is likely that these individuals will not see all the way to the actual moral truth. Rather, they will likely embrace a position that is closer to the moral truth than their society's prevailing norms, but that remains not too far from the prevailing norms. These individuals are not devoid of cultural or biological biases; they merely are somewhat less influenced by those biases than other members of their society. Consider, for example, the case of John Locke, whose Letter Concerning Toleration is a classic in the literature of religious toleration. Locke was a great moral reformer, because he saw that it was wrong to persecute members of other religions. Yet he could not see his way to embracing tolerance for atheists; that was simply too far from the norms of his culture. Thus, after explaining the arguments for religious toleration, he writes, "Lastly, those are not at all to be tolerated who deny the being of God. Promises, covenants, and oaths, which are the bonds of human society, can have no hold upon 19 an atheist."45 Frequently, those who see errors in their society's prevailing norms will attempt to bring about reform. The reformers cause others who did not initially do so to question the misguided norms. Reformers are often effective, for at least two reasons. First, they tend to be more rational than their opponents who favor the status quo. This is because only those with an above-average tendency to form beliefs rationally, and a belowaverage level of bias, will see through the errors in prevailing cultural norms. As a result, in the ensuing debate, the reformers will tend to come across better than their conservative opponents. Second, the reformers will tend to be disproportionately influential members of society. They are more likely, for example, to be authors, professors, other intellectuals, or business or political leaders, as opposed to members of less influential professions. This is because the ability to see through errors in prevailing social norms will be strongly correlated with one's degree of intelligence and reflectiveness, which itself is correlated with belonging to relatively socially influential professions. For example, a talented writer who wants to promote greater tolerance for homosexuality will have more influence on society than a steel worker who wants attitudes toward homosexuality to stay the same. That is an extreme example, but it illustrates the point that people who desire social reform tend to have much more influential social positions than the average member of society. Thus, when society has incorrect values, there is a systematic tendency for forces to arise that push society in the direction of more correct values. Once society has moved some distance in the right direction, a new generation of reformers may arise, realizing that society's values still are not correct, and hence working to push society further along. For example, once Lockean toleration for all theistic religions was accepted, it was then possible for people to see that toleration for atheists should also be accepted. Over the long term, beneficial change can accumulate so that, perhaps after several centuries, a society has moved from horrific values to quite decent ones. This is the sort of process through which our society has arrived at its current set of liberal values. Notice that for this process to work, no great cognitive virtue is required of any individual. It is not necessary that anyone eliminate cultural or biological influences on their thinking, and no one need be capable of seeing the moral truth entirely on their own. What is necessary is only that, at a given point in time, there be some individuals who are capable of seeing certain moral issues a bit more accurately than most of their contemporaries. It is even compatible with the story I have told that almost everyone's moral beliefs be almost entirely determined by genes and culture – but not quite everyone, not quite entirely. Thus, empirical evidence showing that moral beliefs are very often strongly influenced by genes and culture does not undermine my account. The process of moral development is not at its end; no doubt further progress will be forthcoming in future generations. So I do not claim that we now know the precise or complete moral truth. I do claim, however, that we have a mechanism that systematically produces moral progress. Our current practices are, reliably, better than our past practices. As a result, while we perhaps do not quite know how we ought to Locke 1990, p. 64.45 20 act, we know at least some ways that we should not act. We should not hold slaves, for example. Or torture suspects to extract confessions. Or attack people to steal their land. Our condemnation of these sorts of practices is the product of a reliable belief-forming process. 5.5. How Moral Truth Explains We may now return to the explanatory challenge raised at the start of section 5: since moral facts do not produce physical effects, how can a moral explanation for any observable phenomenon ever be correct? How, for example, can the injustice of slavery explain its abolition? In the philosophy of science literature, there are a variety of competing accounts of explanation. On one account, to explain a phenomenon is to identify its cause. This46 seems to be the view presupposed in the literature on moral explanations, and on this view, it is indeed hard to see how a moral fact can explain any observable phenomenon. However, on another account of explanation, to explain a phenomenon is to show how the phenomenon could be inferred (either deductively or probabilistically) on the basis of lawlike regularities together with a specification of initial conditions. This latter47 account of explanation is much friendlier to moral explanations. When I say that slavery was abolished because it was unjust, I am not claiming that the injustice seeped out of the practice and started pushing matter around in various ways (not even the matter in people's brains), leading to a situation where the law books in every country contained anti-slavery provisions. Rather, the line of explanation goes something like this: 1. There is a systematic tendency for human moral beliefs to become more accurate over time. 2. Slavery is seriously unjust. 3. Therefore, it was probable that slavery would in time come to be generally regarded as seriously unjust. 4. Human beings tend to abolish practices that are generally regarded as seriously unjust. 5. Therefore, it was probable that people would in time abolish slavery. Thus, the way in which the injustice of slavery explains its demise is not that the injustice caused the demise. It is that the injustice of slavery, when combined with certain lawlike generalizations about the workings of human beings and human society (propositions 1 and 4), renders the abolition of slavery predictable.48 One might worry that this view only relocates the problem. The above explanation takes for granted in step 1 that society has a systematic tendency to develop more Salmon 1984.46 Hempel 1965; for discussion of the probabilistic case, see pp. 381-93.47 For another account of explanation, see Huemer 2009, section 3. The moral explanation48 here exhibited also satisfies that account, since it cites facts explanatorily prior to the abolition of slavery which raised the probability that slavery would be abolished. This "probabilityraising" is not a causal process; to say that A raises the probability of B is to say that P(B|A) > P(B|~A), where the sort of probability in question is logical probability. 21 accurate moral beliefs over time. My argument for that, in turn, took for granted that human beings have a capacity (albeit a highly fallible one) to apprehend moral truths. But, it might be said, the real problem is how human beings could have a faculty directed at the truth, in an area in which the facts are causally inert. If moral facts don't cause anything (not even our beliefs about them), how could we be at all reliable at identifying them – how could there be a faculty that was any better than chance at identifying moral truths? But this just raises the general problem of a priori knowledge. It is true of a priori knowledge in general that the facts to which it pertains do not cause anything, not even our beliefs about them. For instance, facts about abstract, mathematical objects do not cause anything to happen – this premise, at any rate, is as plausible as the premise that moral facts do not cause anything to happen. Similarly, necessary truths of metaphysics49 do not cause anything to happen. Yet we have knowledge of both mathematical and metaphysical truths.50 The most satisfying reply to the skeptic would be to give a general account of how a priori knowledge works. But that is a very large project and certainly beyond the scope of this paper. A more modest but reasonable reply to the skeptic would be to appeal to the following observations: 1. We have reliable processes for forming some non-moral, a priori beliefs, such as mathematical beliefs and beliefs about certain necessary metaphysical truths. 2. If moral facts lack causal powers, then mathematical facts and necessary truths of metaphysics also lack causal powers. 3. Therefore, if moral facts lack causal powers, then our having a reliable beliefforming process does not require the facts about which we form beliefs to have causal powers. We thus are left with no good reason to deny that there can be reliable moral beliefforming processes. 6. Conclusion This paper has had two goals. The first is to show that debunking arguments fail to refute moral realism. They fail because they rely on general theories about the source of our moral beliefs that are just not credible. These debunking accounts of the source of moral beliefs lack credibility because they afford no explanation for the most important fact about the history of moral thought: the gradual spread of liberalism across the world over the course of human history. Evolutionary theories cannot account for this fact because the spread of liberalism has been too rapid for biological evolution, and because the spread of liberalism in any case has had no empirical And why should we accept either premise? Here is one thought: the only sort of thing that49 can cause a change to occur at a particular time is another change that occurs at a particular time. In the realm of necessary truths, nothing ever changes; hence, no necessary fact can cause any change to occur at any time. Thus, for example, a necessary fact could not cause someone to adopt a belief in that fact. Shafer-Landau (2012, p. 30) argues similarly.50 22 connection to liberals' somehow reproducing more than non-liberals. Purely cultural accounts of the source of morals leave us at a loss to explain why the culture itself has moved in a given direction over time. At first glance, it may seem that many explanations are possible – for instance, perhaps changing technologies or changing forms of economic organization have somehow necessitated different values. But the list of potential explanations dwindles as we try to take into account the entire phenomenon: it is not just, for example, that slavery was abolished in the United States. It is not even just that slavery was abolished in every country in the world. It is that societies around the world have been liberalizing with respect to many different issues – slavery, war, torture, execution, democracy, women's suffrage, segregation, and so on – and this has been going on for centuries. It is very difficult to come up with explanations for this broad phenomenon that don't require us to posit large coincidences. My second goal has been to suggest that we actually have positive evidence for a version of moral realism – a modest, rationalistic, liberal realism. This view holds that human beings have some limited access to objective values, by the same cognitive faculty or process that produces non-moral a priori knowledge; that the objectively correct values are in fact liberal values; but that culture, genes, and other forces may produce biases that pull us away from the purely rational (and liberal) moral beliefs. Given this view, the trend toward liberalization can be explained. At any given point in history, there will be some individuals who are less biased and more morally sensitive than average (but not entirely unbiased). These individuals will push society toward what they, the sensitive individuals, consider morally correct, which will generally mean pushing society at least a little bit closer to the moral truth. Over the long term, beneficial changes accumulate and society's value system approximates the moral truth. Since liberalism is the correct moral stance, this means that society becomes more liberal over time. This, I suggest, is the best explanation on offer for the trend toward liberalization. Until a better explanation appears, therefore, the empirical evidence supports liberal realism. References Adams, Henry. 1891. History of the United States of America during the Second Administration of Thomas Jefferson, vol. 2. London: G.P. Putnam's Sons. Alford, John R., Carolyn L. Funk, and John R. Hibbing. 2005. 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