Does Believing in God Arise from Our Evolved Theory of Mind?

In God and Other Minds: A Study of the Rational Justification of Belief in God (published in 1967 and 1990), Alvin Plantinga offered assessments of the various arguments for believing in God. He concluded that the best argument was based on the analogy between believing in other human minds and believing in the Divine Mind. Although we have direct access to our own minds through subjective experience, we have no direct evidence for other human minds. But except for the radical solipsist, we regard belief in other human minds as a reasonable inference from our experience with other human beings. Similarly, we might conclude that although we have no direct, observational evidence for God's existence, we can reasonably infer the existence of a Divine Mind as a more perfect version of our human mind. Plantinga concluded: "if my belief in other minds is rational, so is my belief in God. But obviously the former is rational; so, therefore, is the latter."

(I doubt this conclusion, however, because it is based on a bad analogy.  I have direct experience of a human mind through my subjective experience of my mind.  But I have no such experience of a divine mind.)

Some evolutionary psychologists have recently been converging on an evolutionary explanation of religious belief that might support Plantinga's insight, because they are uncovering a deep, evolutionary link between believing in other minds and believing in God. But while some of these Darwinian psychologists (such as Justin Barrett) see this as showing that Darwinian science is compatible with the truth of believing in God, others (such as Jesse Bering) see this as exposing belief in God as a fictional construction of the evolved human mind. For those like Barrett, religious belief is an adaptive truth. For those like Bering, religious belief is an adaptive illusion.

In contrast to both Barrett and Bering, some evolutionary theorists (like Richard Dawkins) argue that religious belief is not an evolutionary adaptation at all, but rather a byproduct of our having evolved big brains that are capable of big mistakes.

Barrett lays out his position in his book Why Would Anyone Believe in God?, which I have taken up in a previous post.

Bering has summarized his position in a new book--The Belief Instinct: The Psychology of Souls, Destiny, and the Meaning of Life (2011). Bering has posted a brief excerpt from this book as an essay for Slate.

Bering builds upon the "social brain" hypothesis of Robin Dunbar and others--the idea that the big brains of primates can best be explained as evolutionary adaptations to the social complexity of primate life. The unique complexity of human social life is correlated with the unique complexity of the human mind.

Navigating our way through the intricacies of human social life requires that we have a "theory of mind"--that we be able to read the minds of other individuals as intentional agents whose actions are governed by their beliefs, desires, and goals. This is difficult, because while we have direct, subjective awareness of our own minds, we have no experience of other minds. We must project our own subjective experience onto others and infer that they are intentional agents like us.

Although there continues to be debate as to whether there is any evidence for chimpanzees or other apes having some capacity for a theory of mind, it is clear that human beings are uniquely good at reading the minds of others. There is some evidence that human infants as early as 9-months old begin to understand adults as intentional agents, and they do this in a way that far surpasses what the chimps can do.

This human capacity for mind-reading is probably rooted in the development of the human brain--particularly, the prefrontal cortex--as suggested by some brain imaging studies. Further evidence for this is that autistic people and others who show deficits in their mind-reading abilities are probably suffering from impairment in those parts of the brain necessary for interpreting the subtle cues of intentional agency in others.

Because we have such a powerful neural system for mind-reading, we are easily inclined to see minds everywhere, even in nonliving objects. In the famous experiment conducted by Fritz Heider and Mary-Ann Simmel, the viewers of a film showing geometric figures in motion thought they saw a large triangle "bullying" a "timid" small triangle to steal the affections of a "female" circle.

Similarly, Bering argues, our instinctive theory of mind inclines us to see supernatural minds at work in the universe. Thus, our belief in God's mind is just our overactive theory of mind.

Bering contends that this evolved human instinct for mind reading is responsible for four kinds of illusions--superhuman purpose, superhuman signs, a superhuman afterlife, and superhuman morality.

Our belief in superhuman purpose comes from our projecting mental agency onto the cosmos. We ask about the purpose of life, as if life must be the artificial product of a plan by an intelligent agent with some purpose in mind. Even atheists commonly have some sense of destiny, some vague belief that their life has a purpose.

But if we accept the theory of evolution, Bering insists, then this belief in the purpose of life is a cognitive illusion. We don't have a purpose in life, we simply are. Life has no purpose, it simply is. But our mindlessly evolved theory of mind makes it almost impossible for us to believe that there is no mindful purpose to life.

Our belief in superhuman signs comes from our instinctive inclination to look for hidden messages in natural events as controlled by invisible intelligent agents. It is not enough to know how things happen, because we want to know why they happen. We look for the meaning in things. Consequently, much of religious experience consists in interpreting the supernatural messages in the natural world coming from dead ancestors, spirits, angels, or gods. Even modern scientists continue the tradition of natural theology in considering how the divine order is manifest in nature.

Our belief in a superhuman afterlife comes from our inability to imagine what it would feel like to be dead. We cannot prove to ourselves that we are mortal, because we cannot be conscious of being dead. Thus, as Goethe said, "everyone carries the proof of his own immortality within himself."

Sigmund Freud explained the belief in an afterlife as wish fulfillment, and therefore as an expression of our fear of death. But Bering argues that this wish-fulfillment theory doesn't account for the illusion. We have lots of wishes that we don't assume to be true. So why is the wish to be immortal so easy to believe? It must be because it matches our instinctive intuitions about the continuity of the mind after death, which we can see in the beliefs of young children.

Our belief in supernatural morality comes from our evolved social psychology of morality. We look for people to blame for our suffering. When we can't blame another person, we look for some invisible intentional agent to give meaning to the suffering.

It's not enough for us to know how bad things happen to good people. We want to know why they happen, which implies that everything is ordered by some cosmic mind with a moral purpose. This natural propensity of the human mind to look for a cosmic moral order is so strong, Bering indicates, that even most atheists (according to some psychological studies) believe that "everything happens for a reason."

Bering's evolutionary explanation for this is that human social cooperation requires that we be intensely sensitive to the opinions of others--we care about what others think of us, and this concern for our reputation gives us the incentive for good behavior. That's why gossip is such a powerful tool for enforcing good conduct and punishing bad conduct. This requires a theory of mind by which we see ourselves through the eyes of others.

If we think others are not looking, we are tempted to cheat. But if we think there are supernatural agents always watching us, then we are less tempted to cheat. Believing in supernatural moral spectators would protect us from doing the things that ruin our reputations, and this would be favored by natural selection.

Of course, Bering recognizes, the doctrinal and ritualistic content of religious belief is set by cultural traditions that vary across history and across societies. But underlying this cultural diversity is a basic cognitive illusion that is universal. Bering writes:

By all accounts, the basic illusion of God (or some other supernatural agent) "willfully" creating us as individuals, "wanting" us to behave in particular ways, "observing" and "knowing" about our otherwise private actions, "communicating" His desires to us in code through natural events, and "intending" to meet us after we die is pretty convincing for most people. (195)

And yet, how does Bering know that this is an adaptive illusion rather than an adaptive truth? He admits that his evolutionary account of religion as rooted in an evolved theory of mind cannot disprove the existence of God. After all, evolutionary psychologists like Justin Barrett defend this evolutionary account, while seeing it as perfectly compatible with believing that God allowed human beings to have this naturally evolved theory of mind so that they could discover Him.

Bering agrees with Barrett that science by itself can neither prove nor disprove the existence of God. But still, Bering insists, science can conclude that God's existence is highly improbable. Barrett finds Plantinga's argument plausible: "if my belief in other minds is rational, so is my belief in God." And yet, Bering finds this sort of reasoning silly. Plantinga assumes that believing in the existence of other human minds is comparable to believing in the existence of God's mind. But this is clearly not true. Dealing with other human minds is part of our ordinary human experience. Dealing with God's mind is not.

Bering doesn't realize that this debate has a long philosophical history--from Plato to Cicero to Hume. From Plato's Laws (Book 10) and his Phaedo, we know that Plato understood that the most appealing ground for believing in the divine was to project our experience of mental agency onto the universe, but there are good reasons to doubt the plausibility of such reasoning, as suggested by Cicero--in On the Nature of the Gods--and Hume--in Dialogues Concerning Natural Religion. Although we are innately inclined to see an analogy between human minds and divine minds, it is not clear that the analogy is strong enough to justify religious belief.

Bering doesn't realize that most of what he says about the evolution of religious belief follows the lines of Darwin's reasoning in the DESCENT OF MAN (Penguin Classics, 2004). Darwin saw that "belief in unseen or spiritual agencies" was universal among primitive human beings, and that this probably arose first "when anything which manifested power or movement is thought to be endowed with some form of life, and with mental faculties analogous to our own" (116-117). "The belief in spiritual agencies would easily pass into the belief in the existence of one or more gods. For savages would naturally attribute to spirits the same passions, the same love of vengeance or simplest form of justice, and the same affections which they themselves feel" (118).

Only by deeper rational reflection and observation do we realize that all the order we see in the world does not have to be the product of intelligent and intentional design. As Cicero and Hume suggested, human intelligent design is not the only possible source of order that we observe in the world. For example, in the growth of plants from seeds, we see order arising by nature without mental agency. Furthermore, thinkers like Cicero and Hume recognized the possibility of evolutionary order through the selective retention of heritable traits that enhance survival and reproduction, which can create spontaneous orders that are not intelligently designed by any mind or group of minds.

In the philosophic tradition of Plato, Cicero, and Hume, we can see a deeper question at issue here that Bering passes over quickly without much thought. Can we--or should we--free ourselves of the "adaptive illusion of God"?

On the one hand, Bering seems to think we can't do this. He writes:

It is therefore more than a little foolhardy to think that human nature can ever be "cured" of God by scientific reason. As a way of thinking, God is an inherent part of our natural cognitive systems, and ridding ourselves of Him--really, thoroughly, permanently removing Him from our heads--would require a neurosurgeon, not a science teacher. (200)

On the other hand, Bering rejoices that for the first time in human history, we find ourselves "in the full godless light of this shattered illusion." He admits that this might be detrimental to our moral life, if in fact, we need religious belief to support our morality. But then he concludes: "With or without belief, the consequences for acting selfishly are as much a deterrent as they've always been: those who don't play by the rules will--by and large, more often than not--suffer the human consequences" (201-202).

Plato, Cicero, and Hume would agree that moral order can be based on human nature, human custom, and human judgment, without any religious support. But they also suggested that for many, if not most, human beings, religious belief provides a necessary reinforcement for moral conduct. Darwin suggested the same conclusion in his account of the natural moral sense, in which morality can stand on its own natural ground, even without religious sanction, although religious belief can provide powerful reinforcement for our natural morality.

Some of the political founders of modern liberal republicanism understood this. For example, George Washington, in his Farewell Address, observed:

Of all the dispositions and habits which lead to political prosperity, religion and morality are indispensable supports. In vain would that man claim the tribute of patriotism who should labor to subvert these great pillars of human happiness--these firmest props of the duties of men and citizens. The mere politician, equally with the pious man, ought to respect and to cherish them. A volume could not trace all their connections with private and public felicity. Let it simply be asked, Where is the security for property, for reputation, for life, if the sense of religious obligation desert the oaths which are the instruments of investigation in courts of justice? And let us with caution indulge the supposition that morality can be maintained without religion. Whatever may be conceded to the influence of refined education on minds of peculiar structure, reason and experience both forbid us to expect that national morality can prevail in exclusion of religious principle.

Notice that Washington intimates that "the influence of refined education on minds of peculiar structure" can produce good behavior without religious belief. But "reason and experience" should tell us that most human beings need religious belief as a support for their morality.

Washington helped to establish a new government without a governmental establishment of religion, but one which would secure the free exercise of religion. Doesn't this indicate the best political resolution of this debate between reason and revelation?

If the religious belief supporting morality really is rooted in our evolved theory of mind, then we can rely on it to arise by spontaneous order in any civil society with religious liberty. At the same time, those few who live "in the full godless light of this shattered illusion" can be guided by the moral norms rooted in human nature, human culture, and human judgment.

In a free society, people like Jesse Bering and Justin Barrett can live together, being united by their scientific inquiry into human nature, while being free to disagree as to whether the final ground of explanation is to be found in nature or in nature's God.

A few of the many posts on related themes can be found here, here, here, here, here, here, and here.

A Darwinian Key to Locke

Carl Becker's book The Declaration of Independence: A Study in the History of Political Ideas is a classic study of the Declaration as a historical and philosophical document. Having explained the Declaration as appealing to "higher law"--"the laws of nature and of nature's God"--Becker concludes the book by arguing that the Darwinian science of the 19th century refuted this 18th century notion of natural rights.

According to Becker, the Declaration assumes a transcendentalist view of human beings as created in God's image and thus endowed with the moral dignity that justifies their special claim to "unalienable rights"--a teaching that Becker traced back to John Locke. But Becker thought this Lockean philosophy of natural rights was denied by the Darwinian view of evolution.

When so much the greater part of the universe showed itself amenable to the reign of a purely material natural law, it was difficult to suppose that man (a creature in many respects astonishingly like the higher forms of apes) could have been permitted to live under a special dispensation. It was much simpler to assume one origin for all life and one law for all growth; simpler to assume that man was only the most highly organized of the creatures (the missing link would doubtless shortly be found), and to think of his history accordingly, as only a more subtly negotiated struggle for existence and survival. (274-75)

According to Becker, this supported a Machiavellian view of politics.

In a universe in which man seemed only a chance deposit on the surface of the world, and the social process no more than a resolution of blind force, the 'right' and the 'fact' were indeed indistinguishable; in such a universe the rights which nature gave to man were easily thought of as measured by the power he could exert. (276)

If this were true, then we would have to say that Darwinian science subverts any belief in natural rights, and thus denies the fundamental principles of the American political tradition as well as the modern tradition of human rights. In fact, some of the critics of Darwinian science have drawn this conclusion in arguing that Darwinism is morally and politically dangerous.

Against this, I argue that Darwinian science actually supports Locke's understanding of natural rights as rooted in human biological nature.

In his Two Treatises of Government, Locke justifies natural rights as rooted in the natural desires and natural reason of human beings as animals endowed by God with "sense and reason," as opposed to the "inferior animals" that are moved by "sense and instinct." The natural desires become natural rights when human beings as rational animals reflect on the social conditions for satisfying their desires (FT, #86-92). Because of their strong desire for self-preservation, human beings can recognize the right to life as a natural right. Because of their strong desires for sexual mating and parental care, human beings can recognize the rights of parents to rear their offspring. Because of their strong desire for property, human beings can recognize the rights of property. Murder and theft violate the laws of nature and God, because murder and theft are contrary to "the principles of human nature," which are also contrary to God's law insofar as God's will is evident in the way He has "ordered the course of nature" (FT, #89; ST, #10, 67).

Critical to this reasoning is the thought that human beings as rational animals can understand that to satisfy their desire to receive good from others, they must satisfy the like desire in others as "being of the same nature" (ST, #5).

Human beings are naturally equal, because as members of the same human species, they are born to the same general capacities for reasoning about the satisfaction of their desires. They are naturally free, because they naturally resist being attacked or exploited by those who would rule over them by force rather than consent.

When Locke thus speaks about the law of nature as implanted or written into human nature, some readers see this as contradicting Locke's denial of innate ideas in his Essay Concerning Human Understanding. There he is famous for arguing that the human mind should be conceived as an "empty cabinet" or "white paper" that receives any content coming from experience (I.1.15; I.2.22; II.1.2).

His argument in the Essay assumes, however, a very narrow kind of "innateness"--an invariant trait that appears immediately at birth fully formed without any need for experience. This leaves open the possibility of another kind of innateness--natural propensities or inclinations that develop in response to experience. The first kind of innateness assumes an absolute dichotomy between nature and nurture or instinct and learning. The second kind of innateness allows for the interaction of nature and nurture or instinct and learning. For this second kind of innateness, nature can be nurtured, and we can have instincts for learning.

It is this second kind of innateness that runs through the Two Treatises. So, for example, Locke argues: "we are born free, as we are born rational; not that we have actually the exercise of either: age that brings one, brings with it the other too. And thus we see how natural freedom and subjection to parents may consist together, and are both founded on the same principle" (ST, #61).

Moreover, this natural propensity for human beings to develop into fully rational animals through their rearing by parents is open to "defects that may happen out of the ordinary course of nature," when mental disorders impede the full development of normal human rationality (#60). And, even within the normal range of human rationality, there is variation, in that intelligence is variable across individuals (#54).

This is the kind of innateness that one finds in Darwinian biology. Although Darwin sees human traits as products of an evolutionary ancestry linked to other animals, he recognizes the uniqueness of human beings in their natural capacities for reason, morality, and language. Those capacities are not rigidly fixed instincts that arise automatically and necessarily at birth fully formed. Rather, they belong to our evolved human nature as natural propensities that develop over the life of each human individual in response to cultural experience.

Recent research on how the human brain has evolved for social intelligence and cultural learning confirms this Darwinian understanding in a way that also confirms Locke's argument.

Human beings are unique in their capacity for social reasoning. Other primates might show some ability for "mind-reading" or "theory of mind"--being able to probe the mental point of view of other individuals. But human beings are unique in the extent to which they can infer the desires and beliefs of others as they negotiate the terms of social cooperation as based on a social contract constituted by collective agreement to serve the common good.

Evolutionary psychologists like Michael Tomasello and Robin Dunbar have shown how human infants in their first few years show a capacity for "joint attention"--following the gaze of adults to direct their attention to the same object being attended to by the adults. Subsequently, they learn how to direct the attention of adults to objects the infants are looking at. Other primates don't show this ability for sharing attention, and thus they lack the capacity for language and culture that is built on this shared attention.

This evolved human capacity for shared attention--for getting into the minds of others and reaching agreement on the socially constructed norms of cultural life--is the fundamental presupposition of Locke's understanding of natural rights. How this evolved social psychology allows us to agree on our natural rights and duties is well stated in a passage from Richard Hooker's Laws of Ecclesiastical Polity (I.8.7) that is quoted by Locke (ST, #5):

The like natural inducement hath brought men to know, that it is their duty no less to love others than themselves. For seeing those things which are equal, must needs all have one measure; if I cannot but wish to receive all good, even as much at every man's hand as any man can wish unto his own soul: how should I look to have any part of my desire herein satisfied, unless myself be careful to satisfy the like desire, which is undoubtedly in other men, we all being of one, and the same nature? To have anything offered them repugnant to this desire must needs in all respects grieve them as much as me, so that if I do harm, I must look to suffer; there being no reason that others should show greater measure of love to me, than they have by me showed unto them. My desire therefore to be loved of my equals in nature as much as possibly may be, imposeth upon me a natural duty of being to them-ward fully the like affection. From which relation of equality between ourselves and them that are as ourselves, what several rules and canons natural reason hath drawn for direction of life, no man is ignorant.

Chimpanzees don't have the natural cognitive ability for such social reasoning that leads to the understanding of justice as reciprocity, or the Golden Rule. Only human beings have this ability by virtue of their evolved nature, which supports the historical experience that has brought about our modern Lockean understanding of natural rights and natural duties.

Some related posts can be found here, here, and here.

The Machiavellianism of Our Chimpanzee Politics

So what would Niccolo Machiavelli say about Hosni Mubarak's political career?

Machiavelli might admire Mubarak's rise from a military career to princely rule in Egypt. His military success--particularly in the October War of 1973--showed his mastery of war and his understanding that "good laws" depend upon "good arms."

As Vice President of Egypt, Mubarak became President after the assassination of President Anwar Sadat, so he understood the vulnerability of princes to assassination. Mubarak himself was the target of a least a half-dozen assassination attempts. He understood, as Machiavelli taught, that even the most powerful ruler can be brought down by any assassin willing to lose his life in an attack.

He also understood that if a prince has to choose between being feared and being loved, it is better to be feared, and consequently, he maintained his princely power for 30 years through a declaration of emergency law that allowed him to arrest and terrify his political opponents without due process of law.

His mistake towards the end of his career, however, was in failing to see that even if the prince is feared, he must avoid the hatred and contempt of the people, particularly that coming from the young men. The popular demonstrations of the last few weeks showed that this hatred and contempt coming from the people would make him vulnerable to those ambitious few around him who were looking for the first opportunity to take his power from him. His dependence on the military then left him open to the military decision to force him out of office.

Reports suggest that Mubarak's son--Gamal Mubarak--was pushing him to cling to power, for the obvious reason that Gamal was his successor. The military leadership of Egypt has declared that the Constitution and the Parliament is suspended, and that until elections occur, the country will be represented by Egypt's Defense Minister, Field Marshall Mohammed Hussein Tantawi. Previously, he has been a loyal supporter of Mubarak. But now he appears to be a shrewd opportunist who might have managed Mubarak's ouster.

The leaders of the Egyptian protestors had studied the techniques of non-violent resistance--the techniques of Gandhi, Martin Luther King, and others, as presented in some books by Gene Sharp. Such techniques work only if the police and soldiers refuse to kill the protestors. In this case, the decision of the military leaders to order their soldiers to assume a posture of neutrality deprived Mubarak of the terrorizing force that might have stopped the public protests.

We can see here Machiavelli's political psychology as based on the three or four distinct "humours" or personality traits in any community--the one, the few, and the many.

Every political regime must have one person at the top, someone who exercises the chief executive power. Even in the most primitive societies of foragers, who have no formal ranks of political power, some individuals exercise leadership, particularly in war. And once human beings settled into agrarian states, the position of war leader was transformed into formal military command. Today, even in modern democratic regimes, the chief executive acts as commander-in-chief in time of war.

The one prince is surrounded by those Machiavelli called "the great ones"--the ambitious few or the elites--who naturally want to rule, and thus want to take the place of the prince. Those with military power might be considered a distinctive "humour," or they might be considered as belonging to the ambitious elite. The prince must fear these people the most, because they are the ones who have the ambition to replace him.

The great majority of people have no ambition to rule. They naturally submit to being ruled by the prince and the ambitious few. But they also resist being exploited by the few. They want to be secure in their property and their private lives. Even though they don't want to rule themselves, their hatred or contempt of their rulers will move them to violent resistance or revolution. Even if the prince is feared, a successful prince must avoid the hatred or contempt of the people, and he does this by keeping his hands off their property and their women.

This dark view of politics makes Machiavelli's political realism disturbing to most of us. But it's hard to deny the basic truth of his teaching as a description of political history. In every political community, we see rule by a single person, usually a man, who shows a powerful drive for dominance. Around that alpha male, we see a small group of people--mostly men--who are naturally ambitious for power, and who are the natural rivals of the alpha male, although they will support him if he pulls them into his political coalition. Finally, around the prince and the ambitious few, we see the great multitude of people--men and women--who have no political ambition, who submit to political rule, who seek only security in their private lives, but who can be provoked to rebellion if they feel unduly oppressed by the rulers. Even in democracies, we never see absolute equality, with everyone having equal power, because democratic citizens exercise only indirect and episodic power, as in elections, and they depart from their natural submissiveness only in rare circumstances where their feeling of being oppressed has become unusually severe.

One way to explain this Machiavellian pattern in politics is to say that this shows the biological nature of human beings as political primates ruled by alpha males. That's the argument of Frans de Waal's book Chimpanzee Politics, based on his study of the chimpanzee colony in the Burgers' Zoo in Arnhem, in the Netherlands. Support for de Waal's argument comes from Arnold Ludwig's book King of the Mountain: The Nature of Political Leadership, which is a study of the human political leaders in the twentieth century.

If de Waal and Ludwig are right about this, this would confirm Aristotle's political biology. Aristotle identified the political animals as those animals who are naturally inclined to organize themselves into social groups for collective action, and he identified human beings as similar to those political animals who need "leaders" (hegemones). Moreover, Aristotle observed, since males tend to be more "hegemonic" than females, males are naturally inclined to seek the highest positions of political leadership. Although Aristotle did not identify chimpanzees as political animals, he did recognize that chimpanzees were the animals most similar to human beings, a conclusion that he reached after a meticulous dissection of chimpanzee bodies. Also, there's very little in Machiavelli's political realism that can't be found in Aristotle's political biology--particularly, in what he says about how tyrants preserve their power and what has to be done in times of revolutionary upheaval.

Now I know that the followers of Leo Strauss assume that Aristotle's talk about human beings as political animals by nature is only his "exoteric" teaching, and that his "esoteric" teaching is in agreement with Hobbes--that politics is artificial, not natural, because it depends on the artifice of statesmen establishing political traditions. But, as I have argued in DARWINIAN NATURAL RIGHT, this assumes a false dichotomy between nature and artifice, which ignores the fact that human beings (like other political animals) have natural instincts for social learning, so that political order arises from a complex interaction of nature and nurture. To assert that politics is purely cultural and not natural at all would be to embrace an implausible "blank slate" view of politics. But then the Straussians contradict themselves on this point, because they insist that the utopian teaching of Plato's REPUBLIC is "against human nature," which suggests that there really is some natural structure to human social and political life.

Quoting Chapter 9 of Machiavelli's Prince ("Of the Civil Principate"), de Waal sees the political life of chimpanzees as conforming to Machiavelli's political psychology. Machiavelli writes that when a private citizen becomes a prince through the favor of his fellow citizens, which he calls a "civil principate," the prince comes to power either with the favor of the people or with that of the great. "For in every city, these two different humors are to be found. Thus it is that the people desire not to be commanded or oppressed by the great, and the great desire to command and to oppress the people." Consequently, the great will elevate one of their own to make him prince if he will help them oppress the people; or the people will make one man the prince if he will protect them from the oppression of the great.

Machiavelli explains:

. . . He who comes to the principate with the aid of the great maintains himself with more difficulty than the one who attains to it with the aid of the people--for he finds himself prince with many around him who opine themselves his equals, and because of this he cannot command or manage them in his own mode.

But he who arrives at the principate with the popular favor finds himself alone, and there will be no one or very few around him who are not prepared to obey. Besides this, one cannot with honesty satisfy the great without injuring others, but one can well do that with the people. For the end of the people is more honest than that of the great, the latter wanting to oppress, the former not to be oppressed.

One who becomes prince by means of the favor of the people ought, therefore, to keep them his friends. This is made easy for him, for they ask of him only that they be not oppressed. But one who becomes prince with the favor of the great, against the people, ought above all things to gain the people to himself; which is easily done when he undertakes their protection.

This point about how easy it is for a prince to please the people--by just not oppressing them--is stressed by John Locke in his account of how a "wise and godlike prince" can exercise the executive power without resistance as long as he refrains from oppressing the people. Only foolish princes become so oppressive, Locke observes, that the people must assert their right to resistance.

This is what de Waal saw in his chimps at Arnhem. The alpha male needed to gain the support of the adult females and the children by keeping the peace through impartial intervention into disputes. By contrast, an alpha male who was too dependent on other high-ranking males was insecure, because these ambitious males would look for the first opportunity to overthrow him and take his dominant position.

De Waal explained the political ambition of the adult males--their drive to become the alpha male--as a product of evolution by natural selection, because the dominant males had more access to fertile females, and thus the dominant males would, on average, have higher reproductive fitness.

De Waal concluded that his study of chimpanzee politics sustained Machiavelli's teaching about human politics:

Nearly five centuries ago, Machiavelli described the political manipulations of the Italian princes, popes and influential families such as the Medici and the Borgias without equivocation. Unfortunately, his admirably realistic analysis has often been mistaken for a moral justification of these practices. One reason for this was that he presented rivalries and conflicts as constructive and not negative elements. Machiavelli ws the first man to refuse to repudiate or cover up power motives. This violation of the existing collective lie was not kindly received. It was regarded as an insult to humanity.

To compare humans with chimpanzees can be taken to be just as insulting, or perhaps even more so, because human motives seem to become more animal as a result. And yet, among chimpanzees, power politics are not merely 'bad' or 'dirty.' They give to the life of the Arnhem community its logical coherence and even a democratic structure. All parties search for social significance and continue to do so until a temporary balance is achieved. This balance determines the new hierarchical positions. Changing relationships reach a point where they become 'frozen' in more or less fixed ranks. When we see how this formalization takes place during reconciliations, then we understand that the hierarchy is a cohesive factor, which puts limits on competition and conflict. Child care, playing, sex, and cooperation depend on the resultant stability. But underneath the surface, the situation is constantly in a state of flux. The balance of power is tested daily and if it proves too weak, it is challenged and a new balance established. Consequently chimpanzee politics are also constructive. Human beings should regard it as an honour to be classed as political animals.

Like Aristotle, de Waal recognizes that human politics is unique because of the uniqueness of human language and conceptual reasoning, which allows human politics to express the human rhetorical debate over concepts of the good, the just, and the useful. Nevertheless, de Waal sees in human politics the same spirited desire for dominance that he sees in chimpanzee politics.

This claim that human politics manifests a primate political nature based on rule by alpha males becomes more persuasive if one considers Ludwig's study of political leadership. Ludwig's book shows that the political history of the 20th century confirms the claim of Aristotle, Darwin, and de Waal that male dominance of politics is rooted in human biological nature. Ludwig supports his argument with a meticulous analysis of the 1,941 chief executive rulers of the independent countries in the 20th century. He illustrates his points with lively anecdotes from the lives of the 377 rulers for whom he had extensive biographical information. In addition to this anecdotal evidence, he provides quantitative measures of the behavior of political leaders that confirm his argument.

The political history of the 20th century clearly supports Roberto Michels' "iron law of oligarchy": despite the attempts of socialists to establish absolute equality, every social group and political community shows a tendency to oligarchic rule by those elites ambitious enough to seek power. Moreover, we also see a tendency for power at the top to be taken by single person exercising executive rule.

And, in most cases, these highest positions of power are filled by men. Of the 1,941chief executive rulers in the 20th century, only 27 were women. Of those 27, almost half came to power through their connection to their politically powerful fathers or husbands. For example, Benazir Bhutto rose to power in Pakistan after the assassination of her father. After being expelled and then returning to power, she herself fell to an assassin. Corazon Aquino rose to power in the Philippines after the assassination of her husband. Only a very few women--like Margaret Thatcher--rose to power on their own without any tie to a powerful man. But even in these cases, women like Thatcher were embedded within a male-dominated political world. And their success depended on showing manly propensities--showing that they had "balls."

As indicated by Machiavelli and de Waal, Ludwig's study shows that rulers who oppress the people, and thus provoke hatred and contempt, are exposed to assassination, military coups, and violent revolutions. Those rulers that Ludwig identifies as "tyrants" or "authoritarians" are much more likely to meet a bad outcome than rulers in a democracy. If democratic rulers become unpopular, they can be removed from office by defeat in an election.

The spread of modern democracy--based on limited government with checks and balances--confirms the suggestions of Machiavelli and de Waal that our politial nature can be managed through a balance of power in a mixed regime. The ambitious few can satisfy their ambition by seeking the highest public offices. And the prince can satisfy his desire for dominance by filling the chief executive office. But this drive for dominance is channeled through a constitutional system of limited and balanced powers so that--as James Madison said--"ambition is made to counteract ambition." Consequently, the great multitude of the people who have no ambition to rule, but who only want to be free from oppression, are protected from exploitation by the ruling few, although there remains the threat of popular revolution if the constitutional restraints on power fail.

Ludwig explains modern constitutional democracy as showing how human beings can use cultural institutions to restrain their biological drives for dominance. But I am persuaded by Christopher Boehm's argument that constitutional democracy is rooted in the evolved natural tendency of subordinates to resist being exploited--a tendency that can be seen in chimpanzees as well as human foragers. Thus, we can understand constitutional republicanism as a mixed regime that balances the evolved biological propensities of the one, the few, and the many.

And yet there are some obvious objections that should be answered. Surely many people would object that while the primate model of rule by alpha males depends on the alpha males having greater reproductive success than other individuals, it's not clear that this holds for human rulers.

Ludwig answers this objection by showing that there really is some reproductive benefit for human rulers. He calculates the rate of "sexual profligacy" among married male rulers--their rate of sexual promiscuity, infidelity, or polygamy; and he shows that the most powerful rulers have higher rates of sexual profligacy. The highest rate is 95% for tyrants, and the lowest rate is 40% for democratic rulers. Apparently, the limits on the power of democratic rulers constrain their sexual behavior. But even so, the 40% rate for democratic rulers is a little higher than the estimate of the Kinsey Report for married men in the United States who have had at least one extramarital affair--37%.

Another objection is that the primate model of rule by alpha males fails to account for the potential of alpha females. After all, even among chimps, females have their own dominance hierarchy. And among some primates--particularly bonobos--the females seem to be dominant over the males. Furthermore, we could argue that the human pattern of male dominance is changing as more and more women are beginning to rise to the top.

Ludwig only briefly refers to bonobos, and he doesn't consider the possibility suggested by de Waal that human beings might be "bipolar primates" who combine chimp and bonobo propensities--who might, therefore, be open to female rulers as well as male rulers. Ludwig does suggest, however, that human politics could benefit from having more women in high positions of power so that they can introduce a more "estrogenic approach" to politics that would bring more peace and less war. Here Ludwig would be on the side of Malcolm Potts, who hopes that giving more influence to women will moderate the male propensity to war.

It is not clear to me, however, that this is likely. It is certainly true that women today have more freedom than ever before in modern democracies to pursue political careers. But most of the women who enter politics prefer to concentrate on local politics where they can do some good for their communities. Those women who might pursue the highest offices--women like Maggie Thatcher ("The Iron Lady")--are likely to be high testosterone women who will show all the character traits of manly dominance.

Some of my essays and blog posts on related topics can be found here, here, here, here, here, here, here, here, here, and here.

The Moral Realism of Darwin, Lincoln, and Obama

February 12th will be the anniversary of the birth of Abraham Lincoln and Charles Darwin on February 12, 1809.

Two years ago was the bicentennial celebration of their births. Only a few weeks after his inauguration as President, Barack Obama contributed to this celebration by delivering a speech to the Abraham Lincoln Association in Springfield, Illinois. In the central paragraph of his speech, he recognized the link between Lincoln and Darwin:

Only a union could speed our expansion and connect our coasts with a transcontinental railroad, and so, even in the midst of civil war, he built one. he fueled new enterprises with a national currency, spurred innovation, and ignited America's imagination with a national academy of sciences, believing we must, as he put it, add "the fuel of interest to the fire of genius in the discovery . . . of new and useful things." And on this day, that is also the bicentennial of Charles Darwin's birth, let us renew that commitment to science and innovation once more.

Here Obama quotes from Lincoln's "Lecture on Discovery and Inventions," which is the clearest expression of Lincoln's Darwinian view of human evolution and technology. In a previous post, I have commented on Obama's rhetorical debt to Lincoln and his acceptance of Darwin's science.

Beginning in the 1980s, I have written about the intellectual links between Lincoln and Darwin in various articles and books--for example, in the chapter on slavery in Darwinian Natural Right. But I have learned a lot from some of the recent scholarship related to the Lincoln/Darwin bicentennial. Three books are especially good: Adam Gopnik, Angels and Ages: A Short Book about Darwin, Lincoln, and Modern Life, Adrian Desmond and James Moore, Darwin's Sacred Cause: How a Hatred of Slavery Shaped Darwin's Views on Human Evolution, and James Lander, Lincoln & Darwin: Shared Visions of Race, Science, and Religion. Some of my previous posts on some of this scholarship can be found here, here, here, here, and here.

I see at least six points of similarity between Darwin and Lincoln. (1) Both saw the universe as governed by natural laws, which included the natural laws for the evolution of life. (2) Both were accused of denying the Biblical doctrine of Creation. (3) Both spoke of God as First Cause. (4) Both appealed to the Bible as a source of moral teaching, even as they also appealed to a natural moral sense independent of Biblical religion. (5) Both abhorred slavery as immoral. (6) Both were moral realists.

As I have indicated in previous posts, there is debate about each of these points. But I find that what is most difficult for many people to understand is the last point--their moral realism. Previously, I have taken up this point in my response to Desmond and Moore in my post "Did Darwin Naturalize Genocide?--Or Does Right Make Might?" My reading of Lander's book has stirred me to think more about this.

Here's how I interpret the moral realism of Lincoln and Darwin. Because they see moral and political order as rooted in evolved human nature, they see moral progress as both possible and imperfect. Moral progress is always possible, because human beings can learn how to extend social cooperation and sympathetic concern to ever wider circles of humanity. But moral progress is always imperfect, because human beings will always face tragic conflicts of interest that arise from their complex nature as animals who are both selfish and social, both competitive and cooperative. Consequently, a world of perpetual peace and universal cooperation is impossible. Moral and political history often coincides with military history.

Lincoln showed his moral realism in his handling of the slavery issue. Lincoln always recognized the immorality of slavery, and therefore he disagreed with the proslavery extremists (like John C. Calhoun) who defended slavery as a "positive good." But Lincoln also recognized the imprudence in trying to immediately abolish slavery, and therefore he disagreed with the abolitionist extremists like William Lloyd Garrison who were willing to overturn the Constitutional compromises with slavery.

Lincoln looked for a practical compromise that would allow for the gradual extinction of slavery. He hoped that slaveholders could be compensated for liberating their slaves, while the freed slaves would move to a colony in Africa. He thought this would strike a balance between self-interest and moral concern. To many people today, his colonization plan looks like evidence of racist bigotry. But for Lincoln, this arose from a tough-minded recognition that racial prejudice would make it hard for blacks and whites to live together peacefully. If the freed slaves remained in America, Lincoln predicted, there would be at least 100 years of racial conflict before racial equality could be achieved. For example, Lincoln saw the natural disgust with racial intermarriage as a sign of the natural human disposition to in-group/out-group conflict.

When the proslavery extremists in the American South refused Lincoln's offers of practical compromise and then launched a war of secession, Lincoln was forced to wage war to save the Union as a condition for the ultimate extinction of slavery. Here, again, we see his moral realism. (Let's remember that this year is the sesquicentennial of the beginning of the Civil War in 1861, which will stir new debate about the decisions that led to the war, by far the bloodiest war in American history and one of the bloodiest wars in all of human history.)

We hope to settle moral conflict through persuasion. But when persuasion fails, we must sometimes appeal to force of arms to settle the disagreement. As Pascal observed, we look for the union of force and justice, so that what is just must be strong, or what is strong must be just.

Many American religious believers thought that the Bible should settle such moral disagreements. But as Lincoln noted, the Bible was unclear about the morality of slavery. And so in the Civil War, "both read the same Bible and pray to the same God, and each invokes His aid against the other." This theological dispute was resolved by the military victory of the North.

We see this same moral realism in Darwin's thought. Darwin believed that one crucial element in the evolution of morality was group selection through tribal warfare, because those tribal groups with the moral virtues of courage and patriotism would tend to prevail in war against those groups whose members lacked those virtues. In The Descent of Man (Penguin ed.), he writes:

When two tribes of primeval man, living in the same country, came into competition, if (other circumstances being equal) the one tribe included a great number of courageous, sympathetic and faithful members, who were always ready to warn each other of danger, to aid and defend each other, this tribe would succeed better and conquer the other. Let it be borne in mind how all-important in the never-ceasing wars of savages, fidelity and courage must be. . . . Selfish and contentious people will not cohere, and without coherence nothing can be effected. A tribe rich in the above qualities would spread and be victorious over other tribes: but in the course of time it would, judging from all past history, be in its turn overcome by some other tribe still more highly endowed. Thus the social and moral qualities would tend slowly to advance and be diffused throughout the world. (155)

This competition in war continues today. "At the present day civilized nations are everywhere supplanting barbarous nations, excepting where the climate opposes a deadly barrier; and they succeed mainly, though not exclusively, through their arts, which are the products of the intellect" (153). And we can expect this to continue into the future. "At some future period, not very distant as measured by centuries, the civilised races of man will almost certainly exterminate, and replace, the savage races throughout the world" (183).

This last passage is often quoted by Darwin's critics--people like Richard Weikart and Gertrude Himmelfarb--to support their claim that Darwin promoted the militaristic Social Darwinism that led to Adolf Hitler.

But the intellectual shallowness of people like Weikart and Himmelfarb make it impossible for them to think through the complexity of Darwinian moral realism. We can recognize the evil of Hitler's Nazism, while still recognizing the historical truth that "civilized races" have prevailed in war with "savage races," because the advantages of "civilized" social organization create military superiority. Desmond and Moore show a similar shallowness when they criticize Darwin for his "rationalizing the darker side of tribal conflicts" or "biologizing of genocide."

In his Voyage of the Beagle, Darwin described the revulsion he felt towards the atrocities committed by the European races against the native people of South America, Tasmania, and New Zealand. He lamented: "Wherever the European has trod, death seems to pursue the aboriginal." Describing how "all the Indians are butchered" by the Europeans in Argentina, he observed that those "a little superior in civilization" are also superior in military power, although "inferior in every moral virtue."

And yet while feeling sympathy for the suffering of the "savage races," Darwin also recognized the barbarism in the life of "a savage who delights to torture his enemies, offers up bloody sacrifices, practises infanticide without remorse, treats his wives life slaves, knows no decency, and is haunted by the grossest superstitions" (Descent, 689).

Darwin looked forward to the moral progress that would come with the extension of moral sympathy to all of humanity:

As man advances in civilization, and small tribes are united into larger communities, the simplest reason would teach each individual that he ought to extend his social instincts and sympathies to all the members of the same nation, though personally unknown to him. This point being reached, there is only an artificial barrier to prevent his sympathies extending to the men of all nations and ages.

(Descent, 147)

But Darwin suggests that this humanitarian sympathy will generally be weaker than the love for one's own--for one's own family, friends, and fellow citizens. Consequently, there will always be tragic conflicts between human groups, and when those conflicts become severe, human beings will go to war.

A similar moral realism was expressed by President Obama in his Nobel Peace Prize Lecture in 2009. Obama acknowledged the awkwardness in accepting the Nobel Peace Prize while acting as Commander-in-Chief in two major wars. He stated his admiration for the pacifist morality of Martin Luther King and Mohandas Gandhi. But he recognized that their pacifist morality was unrealistic. He explained: "As a head of state sworn to protect and defend my nation, I cannot be guided by their examples alone. I face the world as it is, and cannot stand idle in the face of threats to the American people. For make no mistake: Evil does exist in the world. A non-violent movement could not have halted Hitler's armies. Negotiations cannot convince al Qaeda's leaders to lay down their arms. To say that force may sometimes be necessary is not a call to cynicism--it is a recognition of history: the imperfections of man and the limits of reason."

Obama defended the tradition of "just war," the moral tradition that tries to combine justice and force by specifying the moral criteria for the justice of going to war and the just conduct of war. Even if one disagrees--as I do--with Obama's claim that the wars in Iraq and Afghanistan are just, one can agree with the moral realism of the just war tradition.

Obama saw the tragic character of war:

"So yes, the instruments of war do have a role to play in preserving the peace. And yet this truth must coexist with another--that no matter how justified, war promises human tragedy. The soldier's courage and sacrifice is full of glory, expressing devotion to country, to cause, to comrades in arms. But war itself is never glorious, and we must never trumpet it as such."

"So part of our challenge is reconciling these two seemingly irreconcilable truths--that war is sometimes necessary, and war at some level is an expression of human folly."

Moral progress is possible in matters of war to the extent that we can enforce standards of just war, but even just war manifests the moral tragedy of the human condition, a tragedy rooted in our evolved human nature.

Of course, Obama's election as President is another example of moral progress. Just as Lincoln predicted, it took America over 100 years of racial conflict before the country could begin moving towards racial equality. The moral progress manifest in Obama's election is especially dramatic because of Obama being the child of a racially mixed couple.

Not long ago, Obama joked that his family dog was a "mongrel" just like him! This seems to be part of a general social change in which racial intermarriage does not provoke as much disgust as it once did. There is no reason to believe that racial conflict will ever be totally abolished. But, at least, we can see this as another example of how moral progress is possible, even if imperfect.

Darwinian Marriage (3): An Exchange with Matt Franck

Today, those of us in the American Midwest are confined to our homes by the Blizzard of '11. For me, it's an opportunity to think some more about "Darwinian marriage."

Matthew Franck is the Director of the Center on Religion and the Constitution of the Witherspoon Institute in Princeton, New Jersey. He is one of our most distinguished graduates at Northern Illinois University, where he earned his Ph.D. in political science, specializing in political theory.

We recently had a brief email exchange, and he has agreed to allow me to post it here.

Matt wrote:

Thanks for pointing me to your blogging on these questions. At the risk of offending an old acquaintance, I will say that I am less and less taken all the time with Darwinian explanations for anything, especially for human behavioral phenomena, and most especially for the explanation of moral norms and their genesis. Your note came just as I was reading Marilynne Robinson's ABSENCE OF MIND, which uses the term "parascience" for the work of, e.g., E. O. Wilson. I think she has something there.

In response to this, I wrote:

But, then, if I understand you correctly, you are impressed by Robert George's biological explanations for moral norms and their genesis, as in his "What is Marriage?" article. If so, then you would agree with him that, for example, marriage would not be a moral norm if human beings reproduced asexually. Right? So our moral nature really does depend on our biological nature as sexual animals who are adapted for conjugal bonding and parental care? That's Darwin's argument for the biological basis for the moral sense.

Responding to this, Matt wrote:

It seems one of us is confused, and I do not rule out that it may be me. But as I understand the argument of George and his co-authors, they are not offering "biological explanations for moral norms and their genesis." Rather, they are tyring to provide a rational understanding of the nature of marriage, as a politico-legal and moral institution, by taking account of our nature, in its fullness, as bodily creatures. It is one thing to say that our biological nature is relevant to moral considerations, and quite another to say that our biology is the cause of our morality.

I agree that if human beings were "made" (whether by design or by evolutionary adaptation) to reproduce asexually, there would be no such thing as marriage. We are instead made--or "adapted"--for conjugal relations. But as we know, the sexual urge (whatever its genesis) is capable of manifesting itself in manifold directions, some of them useful for procreation, some not, and many of the paths down which the sexual urge travels can result in reproductive activity we can condemn as immoral: rape, incest, adultery, polygamy, premarital fornication . . . I cannot see any "Darwinian" grounds on which to condemn any of them, or any of the nonreproductive manifestations of the sexual urge, for that matter: homosexuality, anal and oral sex, sadomasochism, masturbation, bestiality . . . These are not useful activities for the perpetuation of the species, but that does not conclude the question of their morality.

The moral sense seems to have a biological "cause" only in a material sense, as a table's material cause may be the tree from which the wood came. Assuming that Darwinian accounts of biology have any explanatory power for the understanding of human behavior--which I assume here only arguendo--they have nothing meaningful to say about the moral norms governing our judgments of human behavior as right or wrong. For these purposes, we require formal and final causes of morality that cannot be located in our biology.

It is possible that Darwinian explanations shed light on "what people do, by nature, for the most part." (Frankly, I doubt it, but that's another debate.) Granting such a possibility, it does not follow that Darwinian explanations shed light on "what is right or wrong for people to do in pursuit of that human flourishing that truly fulfills our nature." It is the latter sort of argument--speaking of "nature" in teleological terms quite alien to modern biological science--that George et al. are attempting in their consideration of marriage.

As I read this, Matt's argument is that while our biological nature explains the material causes of morality, it does not explain the formal and final causes of morality. If we want to understand what is right or wrong for us "in pursuit of that human flourishing that truly fulfills our nature," which is the concern of George and his co-authors, then we need to speak of nature in teleological terms that are "quite alien to modern biological science."

A Darwinian explanation of morality is defective, therefore, according to Matt, because it asserts a materialist reductionism and denies natural teleology, which contradicts the sort of Aristotelian/Thomistic naturalism manifest in the writing of George and his co-authors.

In reply, I argue that Darwinian ethics is not reductionistic, because it recognizes the emergent complexity of human moral evolution, and it affirms natural teleology, because while it rejects cosmic teleology, it recognizes the immanent teleology in the goal-directed activity of life.

Both of these points can be supported by a careful reading of Darwin himself--particularly, his account of the human moral sense in The Descent of Man (Penguin Books, 2004).

Darwin might seem to be a reductionist when he declares that "there is no fundamental difference between man and the higher mammals in their mental faculties," because "the mental faculties of man and the lower animals do not differ in kind, although immensely in degree" (86, 173).

But Darwin implicitly recognizes that differences in degree passing over a critical threshold can create emergent differences in kind. In the case of human beings, emergent evolution creates at least three points of human uniqueness.

First, human beings are unique in their self-conscious awareness. "It may be freely admitted that no animal is self-conscious, if by this term it is implied, that he reflects on such points, as whence he comes or whither he will go, or what is life and death, and so forth" (105).

Second, humans are unique in their capacity for language. "The habitual use of articulate language is . . . peculiar to man" (107).

Third, humans are unique in their nature as moral beings. "A moral being is one who is capable of comparing his past and future actions or motives, and of approving or disapproving of them. We have no reason to suppose that any of the lower animals have this capacity" (135).

The uniqueness of human morality, Darwin recognized, comes from the human combination of five kinds of intellectual powers--the social instincts that lead humans to feel sympathetic concern for others, the mental faculties that allow humans to judge present actions in the light of past experience and future expectations, the capacity for language that allows a human society to express its approbation or disapprobation of conduct, and, finally, the human capacity for learning by habituation (121-22).

From this, Darwin concluded, "our moral sense or conscience becomes a highly complex sentiment--originating in the social instincts, largely guided by the approbation of our fellow-men, ruled by reason, self-interest, and in later times by deep religious feelings, and confirmed by instruction and habit" (157). Consequently, the moral progress of humanity has come mostly through cultural evolution, as human beings learn by experience what is most conducive to their individual and social happiness (163, 169, 682, 688-89). One fundamental feature of that moral progress is the extension of moral concern to ever-wider circles of humanity based on the golden-rule principle of justice as reciprocity, which "lies at the foundation of morality" (147-49, 151, 156-58).

This human moral experience is teleological in the sense that we act for the sake of those natural ends or purposes that we judge to be fulfilling of our natural desires. Darwin's science of evolution denies any form of cosmic teleology, which would present the evolution of the world as a progressive unfolding of a design somehow inherent in the beginning. But denying this sort of cosmic teleology does not subvert the Aristotelian teleology manifest in human morality.

Contrary to Matt's assertion that natural teleology is "quite alien to modern biological science," teleological reasoning is a necessary part of modern biology. Ernst Mayr was one of the most prominent evolutionary biologists of the past century. And he insisted: "Aristotelian why-questions have played an important heuristic role in the history of biology. 'Why' is the most important question the evolutionary biologist asks in all of his researches" (1982, p. 89).

Although Darwinian biologists have to be skeptical about any cosmic teleology, they see Aristotelian teleology in the goal-directed life of organic entities and processes as natural adaptations shaped by evolutionary history. After all, even Aristotle himself, who was a biologist, looked to biological phenomena as displaying the clearest manifestations of natural teleology.

Therefore, to apply functional reasoning to derive moral judgments from biological facts does not violate the spirit of modern evolutionary biology. From the perspective of Darwinian biology, it is reasonable to maintain that the human species has evolved to show natural inclinations that separate human beings from other animals, and that the fulfillment of these natural inclinations in moral and political life conforms to the purposes of our evolved human nature.

As I have indicated in some other posts, Thomas Aquinas rooted his understanding of natural law in the biological science that he had learned from Aristotle and Albert the Great. Arguing that "the good is the desirable," Aquinas could explain natural law as the satisfaction of natural desire, so that "everything to which human beings are inclined by their nature belongs to the natural law" (ST I, q. 5, a. 6; I-II, q. 94, aa. 2-3). He could see the levels of natural law as corresponding to the generic traits that human beings share with some other animals, the specific traits that are unique to human beings generally as a species, and the temperamental traits that vary across individuals.

The biological character of Aquinas's reasoning about natural law as rooted in natural desires is clear in his account of marriage and familial bonding. Citing Ulpian, Aquinas declares that marriage is natural because it satisfies natural desires that human beings share with some animals. He speaks of the human disposition to marriage as a "natural instinct of the human species" (ST, II-II, q. 57, a. 3; Suppl., q. 41, a. 1; SCG, bk. 3, chap. 123).

On Aquinas's account, the primary natural end of marriage is to secure the parental care of children, while the secondary natural end is to secure the conjugal bonding of male and female for a sexual division of labor in the household. Among some animals, Aquinas observes, the female can care properly for her offspring on her own, and thus there is no natural need for any enduring bond between male and female. For those animals whose offspring do require care from both parents, however, nature implants an inclination for male and female to stay together in order to provide the necessary parental care. Just as is the case for those animals whose offspring could not survive or develop normally without parental care, human offspring depend upon parents for their existence, nourishment, and education. To secure this natural end, then, nature instills in human beings natural desires for sexual coupling and parental care. Even if they do not have children, however, men and women naturally desire marital union because, not being self-sufficient, they seek the conjugal friendship of husband and wife sharing in household life.

Aquinas can see the naturalness of monogamy, the partial naturalness of polygyny, and the unnaturalness of polyandry based on his understanding of the biological nature of marriage as directed to the natural ends of parental care and conjugal bonding.

Darwinian science confirms this biological understanding of marriage as rooted in evolved human nature. The Darwinian account of marriage was first stated by Darwin himself and then elaborated by Edward Westermarck. More recent research has filled in this science by explaining the genetic, neurophysiological, and cultural bases of marital bonding.

In "What is Marriage?," George and his co-authors revive Aquinas's biological account of marriage. Darwinian science supports that account by explaining its roots in evolved human nature.

But what about the moral debate over homosexuality and gay marriage, which is the primary concern of the article by George and his co-authors? What would a Darwinian ethics suggest about how we should conduct this debate? If we look to what Darwin says about the various elements of the moral sense, we can see the various considerations that go into such a debate. First, a moral sense requires a sympathetic concern for our fellow human beings and for principles of justice as reciprocity. In the past, the hatred for homosexuals has motivated legal punishment for their behavior, as in the Old Testament teaching that homosexuals should be stoned to death. But now, most of us--including people like George--recognize that this is wrong, because homosexuals should elicit enough fellow-feeling from those of us who are heterosexual that we will refrain from persecuting or killing them. Clearly, Old Testament religion has not provided proper moral guidance on this issue.

We can see that homosexuality is unnatural to the extent that it cannot eventuate in natural procreation. But, of course, homosexuals can become adoptive parents and thus satisfy their natural desire for parenting. Moreover, homosexuals can satisfy the natural desire for conjugal bonding, regardless of whether they become parents.

Since much of morality turns on social approbation or disapprobation based on what we judge to be the common good of society, and since heterosexual marriage and parental care are naturally important for the common good, we need to decide whether or not homosexuality and gay marriage pose any danger to the goods of heterosexual marriage and parental care.

George and his co-authors think that legalizing gay marriage will destroy heterosexual marriage and parental care. How plausible is that? If heteosexual marriage really is as deeply natural for most human beings as they say it is, how likely is it that it would disappear if gay marriage were to be generally legalized? I don't find this very likely. Moreover, I suspect that lesbians are likely to be more faithfully monogamous (on average) than are heterosexual men. But, of course, this question, like all the others related to the gay marriage debate, is a question of practical judgment that can only be settled by practical experience.

Darwinian ethics would suggest that morality depends mostly on social habits and customs shaped in civil society--in families and other social groups. It would seem, then, that the institutions of marriage and family life depend more on the spontaneous orders of society than they do on legal coercion by the state. George and his co-authors disagree. They think that marital institutions are impossible if they are not created by legal licensing. On the other hand, much of what George and his co-authors say about marriage as having a moral reality independent of the state contradicts what they say about the necessity of legal licensing.

Even if many of us conclude that homosexuality is immoral, and therefore that it should be open to social disapprobation, it's not clear that the social good would be served by enforcing this social norm through legal coercion. Surely, most of us can recognize the practical wisdom in Aquinas's principle of liberal jurisprudence that it is not proper for human law to prohibit all vices. For, as Aquinas writes:

Human law is established for the collectivity of human beings, most of whom have imperfect virtue. And so human law does not prohibit every kind of vice, from which the virtuous abstain. Rather, human law prohibits only the more serious kinds of vice, from which most persons can abstain, and especially those vices that inflict harm on others, without the prohibition of which human society could not be preserved. For example, human laws prohibit murders, thefts, and the life (ST, I-II, q. 96, a. 2).

This liberal principle of jurisprudence seems to have been adopted by the New Testament Christians. For example, Paul warns the Corinthians against sexual immorality (such as incest), and he recommends that those committing such immorality be banished from their religious community. But, otherwise, he teaches toleration. "It is no concern of mine to judge outsiders. It is for you to judge those who are inside, is it not? But outsiders are for God to judge" (I Corinthians 5:12-13).

It is not surprising that John Locke quotes this New Testament teaching in his First Letter on Toleration as supporting a policy of toleration.