Natural Right and the Origin of the Species
Abraham Lincoln and Charles Darwin were born on the same day, February 12th, 1809. This fact has scarcely gone unnoticed as the English speaking press celebrates their two hundredth birthday. Less notice has been paid to the fact that the two men made their mark at the same time. The Origin of the Species was published in 1859, about a year and a month after Lincoln’s last debate with Stephen Douglas, and a year before Lincoln’s election as President. This is as large a coincidence as their near simultaneous nativity. If Lincoln’s return to political life was triggered events beyond his control, Darwin could easily have written The Origin decades earlier. Call it one of the Creator’s little jokes.
It is a joke worth pondering. At first glance, the two seem have had little more in common than great fame achieved at the same time. Darwin was born to modest, if quite comfortable wealth. He had famous ancestors. He enjoyed a first class education in one of the world’s most fertile intellectual centers, and his achievements were those of a research scientist. He wrote books. Lincoln was famously born in less than modest circumstances to families of no report. He was just as famously self-educated. His work was the work of the great statesman, and he wrote speeches.
This has not stopped writers of ambitious imagination from trying to argue that the two were, somehow, up to the same thing. Typical of such efforts is Adam Gopnik’s Angles and Ages.1 For Gopnik, “Lincoln and Darwin are both emblematic figures in the spread of bourgeois liberal democracy, and the central role for science that goes with it.” Both helped to shape our “moral modernity,” our shift from ordered, hierarchical views of human society and the larger world around it, to a more leveled, horizontal view of being.
In many ways, Adrian Desmond and James Moore bring Darwin and Lincoln even closer together by focusing exclusively on Darwin. In Darwin’s Sacred Cause,2 they argue, provocatively, that Darwin’s vehement opposition to slavery largely determined the trajectory of his research and biological speculation. Pro-slavery theorists frequently argued for the separate creation of the different races, as that made racial distinctions more like differences between species; in reply, Darwin’s theory of common descent secured the kinship of all mankind.
Both books are fascinating, but neither asks the most important question. It is at least plausible that Darwin’s theory owes its origin more to political motives than anyone has hitherto expected. By contrast, there is no doubt that Lincoln’s politics rested heavily on a theory. The American Revolution ushered in an age in which political action across the globe would be explained and defended and to a remarkable degree guided by scientific, religious and sometimes romantic and quazi-scientific speculations about nature and history. Lincoln built his argument against slavery squarely on the founding document. If all men really are “endowed by their creator with certain unalienable rights,” then slavery is everywhere and always wrong and the only legitimate form of government is one which derives its powers from the consent of the governed. Well, are they?
Science may not be competent to speak about Nature’s God, but it is surely competent to speak about the laws of nature. Does Darwin’s interpretation of human nature and its origins support or undermine Lincoln’s natural right argument? I am not much interested here in Darwin and Lincoln as historical figures. I am interested in Darwinism as a contemporary, working theory of biology, and with Lincoln’s argument as a coherent and plausible position in the history of political philosophy. I will argue that in fact natural right has been rediscovered independently by modern Darwinian biology, and that it largely confirms Lincoln’s understanding of human nature.
Statesmanship and Political Philosophy
According to his own account, Lincoln returned to politics from private life in 1854 because of his alarm at the repeal of the Missouri Compromise. In order to reduce the enormous friction resulting from the slavery controversy in Congress, Senator Stephen Douglas engineered a radical change in federal policy. Prior to the Kansas-Nebraska Act, the territories carved out of the Louisiana Purchase were divided by federal law into those in which slavery was allowed and those in which it was strictly forbidden. Douglas’ policy of “popular sovereignty” would allow the people of each territory to decide for themselves whether or not to adopt a slave code. The 1854 act effectively opened up new federal territories to the expansion of slavery.
Popular sovereignty over slavery could be defended by reference to the basic moral principles of American government. Douglas says in Chicago in July of 1858
If there is any one principle dearer and more sacred than all others in free governments, it is that which asserts the exclusive right of a free people to form and adopt their own fundamental law, and to managed and regulate their own internal affairs and domestic institutions.3
Without questioning Douglas’ sincerity in asserting this principle here, one may notice that it had certain tactical advantages. It allowed him to defend popular sovereignty in the name of abstract principles without having to consider the actual outcomes of that policy. That way he could encourage both sides in the slavery controversy to imagine that the policy would work in their favor. Second, it meant that anyone who takes issue with his policy can be cast as an enemy of liberty.
Lincoln responds to this argument by going over its head. Popular sovereignty is right, so Douglas argues, because a “free people” have a sacred right to adopt their own fundamental law. But why do a free people have that right? By appealing to a standard of natural right, Lincoln is able to show that the right of any people to self government is inconsistent with the enslavement of any other people. But Lincoln was a statesman, and not a political philosopher. His natural right argument is made in as bare bones a fashion as possible, for the sake of clarity and to avoid any question that is unnecessary to his purpose. I will try to lay that argument out a little more explicitly than Lincoln did, and highlight some of its background assumptions.
Natural right means some standard of justice that exists by nature. The closely related term “natural rights” means claims of justice made by one person on behalf of himself and against other persons or groups of persons. There two ways in which right or rights might be said to be natural. One is if the assertion of a principle of justice or a claim of right were made at least in part by instinct. Just as a human being seeks food and shelter by nature, so perhaps he is encouraged by natural inclination to demand a certain treatment for himself, or be offended even by an injustice in which he is not involved. It is possible that such things as a sense of reciprocity, or an abhorrence of incest, develop spontaneously in human societies. If so, then nature acts as a force influencing moral consciousness and behavior.
A second way in which justice might be natural is if it satisfies certain natural desires. Health and shelter are by nature good for human beings, but neither medicine nor architecture grow spontaneously. Rather, the latter are artificial means which are right, if in a non-moral sense, because they solve natural problems and achieve natural goals. Likewise, justice may be something good for human beings by nature as they cannot live well apart from one another and cannot live together without it. But it surely requires the more or less deliberate institution of laws and regimes.
In fact, any account of natural right needs justice to be natural in both senses. If there is not some natural inclination to recognize justice and injustice, natural right is probably impractical. If human beings did not need justice, or if it appeared spontaneously, natural right would be unnecessary. Lincoln argues that justice is natural in both senses. In a famous fragment thought to date from 1854, Lincoln makes a familiar argument about the ends of government:
The legitimate object of government, is to do for a community of people, whatever they need to have done, but can not do, at all, or can not, so well do, for themselves—in their separate, and individual capacity …The desirable things which the individuals of a people can not do, or can not well do, for themselves, fall into two classes: those which have a relation to wrongs, and those which have not.4
These are the ends of government recognized by the natural right tradition going back to Aristotle and Plato.5 By coordinating their efforts people can achieve a greater level of security and prosperity than they can on their own, and better maintain themselves against deviant behavior.
But society and government involve concentrations of power and so raise new opportunities for some to exploit others. Natural right thinking comes into its own in addressing two interrelated questions: how are the powers of government to be allocated among its members, and how are the benefits of social and political organization to be distributed? At the beginning of the natural right tradition in philosophy, Aristotle answered the question in this way: powers are to be allocated to those who are best able to use them for the common good. Benefits are to be distributed in whatever way is best for the society as a whole, and not, as commonly happens, given as spoils to those who have the powers.6
Between Aristotle and Lincoln come Christianity and then modernity. Lincoln can take the idea of equality of rights largely for granted, even among the advocates of slavery; for if the latter believe that they had to right to rule over Negroes, they nonetheless believed in some measure of equal rights among Whites. Given that general notion of political equality, there are two ways to defend it as naturally right. Lincoln used both of them.
The first is what we may call the negative natural right argument. Every existing regime makes a claim to serve justice and the common good. This is true even when a small portion of the population controls all the powers of government and uses it to exploit the rest. Lincoln notes that this is the same among the slaveholding class.
These arguments that are made, that the inferior race are to be treated with as much allowance as they are capable of enjoying; that as much is to be done for them as their condition will allow. What are these arguments? They are the arguments that kings have made for enslaving the people in all ages of the world. You will find that all the arguments in favor of kingcraft were of this class; they always bestrode the necks of the people, not that they wanted to do it, but because the people were better off for being ridden.7
The negative natural right argument needs merely to establish that all such arguments are unfounded. All claims made on behalf of kingcraft or oligarchy, that the whole is better off if a few eat while others do all the work, are lies.
The negative position is very strong for the simple reason that it involves only tearing down bad arguments and requires no building of its own. It is not hard to show that the exploiters are not entitled to their position either by natural superiority or by divine appointment. “If it were possible for men who exercise their reason to believe, that the divine Author of our existence intended a part of the human race to hold an absolute property in, and an unbounded power over others,” speculates Thomas Jefferson, then “the inhabitants of these colonies might at least require from the parliament of Great-Britain some evidence, that this dreadful authority over them, has been granted to that body.”8 The negative argument rests on the firm but reasonable confidence that such arguments will always fail.
But the negative argument contains within it the seeds of a positive defense of natural right. Why do the practitioners of kingcraft and despotism make such arguments in the first place? Does it not suggest at once a universal awareness that political authority needs to be justified by reference to the common good, and that even the tyrant recognizes that his subjects are in fact morally capable creatures? Lincoln went to considerable trouble to demonstrate the existence of a guilty conscience on the part of slave holders. The fact that the South cooperated in the banning of the transatlantic slave trade, that slave dealers were despised and distrusted, that so many slave owners voluntarily manumitted their slaves at great cost to themselves, these things he introduced as evidence.
It is your sense of justice, and human sympathy, continually telling you, that the poor negro has some natural right to himself—and that those who deny it, and make mere merchandise of him, deserve kickings, contempt, and death.9
This may not have been well designed to make friends below the Mason-Dixon Line, but it makes the point for a moral sense well enough.
But what is it precisely that someone is sensing when the moral sense is activated? It involves sympathy, as Lincoln recognized; but it is not limited to sympathy. A few lines later he describes it in precise and dispassionate terms.
I trust I understand, and truly estimate the right of self-government. My faith in the proposition that each man should do precisely as he pleases with all which is exclusively his own, lies at the foundation of the sense of justice there is in me. I extend the principles to communities of men, as well as to individuals. I so extend it, because it is politically wise, as well as naturally just.
Here, of course, is the decisive answer to Senator Douglas. There is such a thing as the common good, something that is not merely reducible to the interests of the individual members of a community. For that reason a people may be said to have a collective right to make “their own fundamental law, regulate their own internal affairs and domestic institutions.”
But just as surely as there is an irreducible collective interest, so there is an imperishable individual interest apart from that of the larger whole. Just as a man cannot take for his own private use what belongs to the whole community without committing a grave injustice, so the right of the community to self-government cannot justify the enslavement of any individual. Lincoln’s argument manages to do what Aristotle did over the course of his Nicomachean Ethics and Politics: he steered between the two great temptations of political theory. Socialist models fail by ignoring the irreducibly private sphere. Libertarian models fail to recognize that the individual human being cannot be understood apart from membership and interaction in human communities.
This way of stating the principle of justice doesn’t quite tell us how to distribute the benefits of the community between the collective and the various individual interests, but it does tell us that all the individual interests have to be recognized. It does not answer the closely related question how authority should be allocated among the members of the political community. So Lincoln goes on.
Judge Douglas frequently, with bitter irony and sarcasm, paraphrases our argument by saying: “The white people of Nebraska are good enough to government themselves, but they are not good enough to govern a few miserable negroes!!”
Well I doubt not that the people of Nebraska are, and will continue to be as good as the average of people elsewhere. I do not say the contrary. What I do say is, that no man is good enough to govern another man, without that other’s consent. I say this is the leading principle—the sheet anchor of American republicanism.
He grounds this in the Declaration of Independence, according to which every government is instituted to protect the inalienable rights of all persons under its jurisdiction, and can only obtain its just powers from the consent of the governed.
The classical political philosophers had argued that political power ought to be distributed according to virtue. He should get the most authority who is most fit to exercise it for the good of the city. Lincoln certainly would not deny that some men are better fit for command than others;10 but he argues that political authority is allocated not on the basis of virtue but by asking who has a right to what. “Allow all the governed an equal voice in the government, and that, and that only, is self-government.” The implication here has to be that while men vary from one another in respect of many capabilities, they do not differ from one another in moral capability. While one person may be better than another, each person is equally fit to govern himself.
Two fragments in Lincoln’s hand, apparently dating from 1854, give us a glimpse of the deeper argument behind Lincoln’s rhetoric.11 In one, he argues that any argument by which A may justify enslaving B will work for some third person against A.
You say that A. is white, and B. is black. It is color, then; the lighter having the right to enslave the darker? Take care. By this rule, you are to be slave to the first man you meet, with a fairer skin than your own.
You do not mean color exactly?—You mean the whites are intellectually the superiors of the blacks, and, therefore have the right to enslave them? Take care again. By this rule, you are to be slave to the first man you meet, with an intellect superior to your own.12
The argument here is that liberty cannot be secure if it is founded on anything that is susceptible to differences of degree. If it is a matter of more or less, one always runs the risk of running into someone with more. On the other hand, if liberty rests on a species characteristic then it can be secure against all claims by other persons. Whatever this thing is that human beings possess by nature and that guarantees the right of each to self-government, it must be something that distinguishes all human beings from the creatures they are allowed to own and exploit.
But in another fragment, Lincoln seems to want an even deeper, metaphysical foundation for liberty. In a fragment, apparently on self-evident truth, Lincoln argues that
all feel and understand it, even down to the brutes and creeping insects. The ant, who has toiled and dragged a crumb to his nest, will furiously defend the fruit of his labor, against whatever robber assails him. So plain, that the most dumb and stupid slave that ever toiled for a master, does constantly know that he is wronged.
This bit about brutes, and creeping insects, and ants may be taken to be a bit of rhetorical excess, worth even less in an unpublished fragment. But I think it revealing.
Lincoln was attracted to natural right because he wanted a moral foundation for human liberty that was at least as extensive, at least as universal, as human nature itself. It would be even better for his purposes if it were more extensive than that. If human beings alone are capable of moral deliberation in the full, conscious sense, this does not mean that more primitive forms of justice might not be observed among other creatures. If one wishes to see justice properly praised, wouldn’t it be helpful if it exists even among the brutes and creeping things? Just as Lincoln was preparing his thoughts in private, in advance of his great work, Darwin was moving toward the publication of The Origin of the Species. It would take a while, but Darwin’s successors would discover that Lincoln was right, even about the bugs.
The Natural History of Right
The history of justice does not begin with human beings, nor has it ever been limited to that species. This is evident in the eusocial insects13, which Aristotle recognized as political animals14. These insects have been extraordinarily successful in Darwinian terms. Bees are ubiquitous. Honey bee colonies may consist of nearly a hundred thousand workers, and are productive enough to supply their own needs and meet the human demand for honey. Ants are even more prolific.
Although they represent only 2 percent of the approximately 900,000 known insect species in the world, they likely compose half the biomass. In a patch of Amazonian rain forest near Manaus, where a measurement was actually made, social insects composed 80 percent. Ants and termites alone composed nearly 30 percent of the entire animal biomass in this same sample, and ants alone weighed four times as much as the combined mammals, birds, reptiles, and amphibians.15
It is possible to detect the formic acid produced by ants from a plane flying over the rain forest.
The extraordinary productivity of the eusocial insects rests on a division of labor. A colony of attine leaf-cutters may have a population of hundreds of thousands or even millions of ants, but it usually has only one reproductively active individual.16 The queen is entirely responsible for sustaining the population. This frees up the rest of the ants to tend the young, to clean, maintain, and extend the complex arrangement of rooms and tunnels that makes up the nest, to forage for plant material and tend the underground gardens a where nutritious fungus is grown, and to defend the colony against invaders. This division of labor allows the colony to function as a superorganism, a society of individual creatures whose behavior is almost as tightly integrated as that of the cells and organs that make up their individual bodies.
Without Darwinian analysis, the moral dimension of colonial organization would be invisible. Cooperation frequently requires sacrifice. One partner must forgo or at least delay gratification on behalf of another or of the group. For eusocial insects, nearly every member of a very large society has to give up the opportunity to reproduce. At first glance this makes no sense. Genetic selfishness would appear to be a simple requirement for all Darwinian creatures.
Every organism is the offspring of a long and unbroken line of successful self-replicators. If an individual organism behaves in a way that prevents it from passing its genes on to the next generation, then its line comes to an end. If a gene or set of genes codes for behavior that inhibits successful reproduction, then selection pressure will, sooner or later, eliminate those genes from the gene pool. Yet the workers in eusocial insect societies appear to behave in a genetically altruistic way. How does the worker get the genes that code for her behavior back into the gene pool without a chance to have her own offspring?
The answer is that her mother may produce not only vast numbers of workers, but many virgin queens and drones who themselves share the genes of their worker sisters. By sacrificing her own opportunity to reproduce in favor of a queen who lives a much longer life, the worker gets many more copies of her own genes into the next generation than she could do by striking out on her own.
However, as cooperative behavior emerges, it gives rise to the temptation to cheat. A bee or ant worker who has a choice will do far better to support the common interest of the hive or colony than to try to reproduce on her own; but why not produce a few eggs on the side? Since the worker is unlikely to have a chance to mate, the unfertilized egg will be male and every one of his genes will come from his mother. If he gets to mate, that represents a big addition to his mother’s reproductive success.17
Of course the worker bee is not making conscious decisions about her behavior. Whether she is conscious at all is probably an unanswerable metaphysical question, but her behavior is certainly tightly regulated by inherited factors. What we are talking about is different decision sets, coded by genes, responsive to some degree to the environment, and subject to natural selection. If the worker cheats the colony successfully, more individuals in the next generation will inherit the tendency to behave just as she did. This represents an existential threat to the unity of the superorganism, and thus will be self-defeating in the long run. If the superorganism is to survive, which is in the genetic interest of all its members, a means must be found to enforce the social contract.
The most reliable way to do that is to turn off the reproductive organs of the workers. In many ant species, the workers are sterile and thus have no temptation to reproduce on their own. But in those species that lack a morphologically specialized queen and worker class, all females can potentially reproduce. Among some bee species, reproductive violations are policed by the queen, who eats any eggs that she does not recognize as her own. Sometimes the workers destroy one another’s eggs.18
In the ant species Harpegnathos saltator, a founding queen enjoys a reproductive monopoly over the two to five years of her life. As her fecundity decreases, however, a group of mated workers (or gamergates) begins to battle for dominance. After a dominant class of gamergates has emerged, both the former and subordinate individuals display a range of agonistic behaviors directed toward workers showing signs of fertility. All these behaviors have the same function: to preserve the social contract on which the colony depends.19
The sacrifices that they encourage are ultimately selfish in a genetic sense. They have to be if they are to be maintained over the generations. But they are genuinely altruistic, as that term is used in biology, in the short run. Altruistic behaviors cannot be reduced to genetic selfishness; rather, genetic preservation and altruistic behavior exist in a dynamic relationship with one another, and that is the means by which the species form is maintained.
In every eusocial species, at the heart of the social organization is a social contract. The short term interest of at least some individual members is subordinated to the common interest of the superorganism; in return, the interest of each member is better served than it would if without the contract. That is the basis of justice everywhere and always. In some cases there is a difference between what an individual worker ought to do (serve both the common interest and her own long term interest) and what she is tempted to do (sacrifice both for short term reproductive gain). Where there is temptation, even in a purely functional sense, a moral dimension has emerged.
The same kinds of social contracts are observed also in those aggregates of cells that make up complex organisms such as horses and Homo sapiens. Of all the cells that make up the various human organs, only the sex cells have the chance to reproduce beyond the life of the individual. Every other cell in the body belongs to a doomed line. But that magnificently altruistic behavior is, of course, genetically selfish as well; for the sex cells have the same genes as those in the heart and kidneys. The proof that this arrangement is genuinely political is evident in the fact that the social contract is sometimes broken in a revolutionary act by groups of cells. We call such a rebellion cancer.
Nor do social contracts in nature always involve a direct sacrifice of reproductive privilege. Cleaner fish forage for parasites inside the mouths of large predators, their clients. In exchange for this service, which promotes the health of the latter, the clients must refrain from eating the cleaners. Occasionally a client fish will cheat, but the result is that the cleaner fish stations will stop responding to his requests. Vampire bats will often share blood with one another after a long night of feeding.20 This is a vital insurance policy, as they must have a meal about every fifty hours to survive, and their food source, mostly herds of large animals, can move around unpredictably. It turns out that the Demodus rotundus has relatively large neo cortex for a bat, and this is thought to be related to the need to keep track of who shares and who does not. A client fish who eats his cleaner after he is serviced, or a vampire bat that accepts charity but does not return it, these are examples of cheating that would break the system if not controlled. They are controlled.
The Natural History of Equality
Simple cells are very probably automatons. The same may well be true of insects, but it is almost certainly not true of mammals. We know this, if we know it, the same way we know that other human beings are sentient: by analogous reasoning, each from his own private experience and the behavior of others. Consciousness represents an existential leap in the history of life. Plants and protozoa are robustly distinct from non-living things in so far as their behavior cannot be understood without recognizing that they are trying to do something. It doesn’t matter whether they have any awareness of what they are trying to do. What does matter is they can succeed or fail, flourish, or decline and die.
Mammals are the same, but they are also capable of pain and pleasure, satisfaction and dissatisfaction. This opens up a second existential dimension. A mammal can have a good or a bad life in sense of conscious satisfaction independently of whether the creature successfully reproduces or not. Just as an attine worker spends its day digging, farming, and leaf cutting, and not trying in any direct way to achieve genetic replication, so mammals spend their days eating, mating, or fighting for the chance to mate.
But the mammals, much more than the hymenoptera, live to serve their own agendas. The space between the simple Darwinian mechanics of reproduction and species preservation, on the one hand, and the rich inner life that sentience affords, on the other, would seem to be radically greater in human beings than in any other creature. Human consciousness operates in an extraordinarily complex, socially constructed world, woven of language and highly remodeled passions. It is easy enough to forget that we are animals at all, until nature calls in one way or another.
This distance between humans as Darwinian organisms and humans as socially constructed and constructing creatures lead many thinkers to deny any relevant connection between the two beings and to erect a high wall of separation between the physical and the social sciences. Thus to apply terms like justice, morality, and the social contract to the behaviors of animals, let alone bees and slime molds, is viewed as at best a metaphor and more likely as an outright distortion.
This is wrong. Human beings, like other mammals, form social groups because it is advantageous to the members to do so. Our societies have the same function, on a basic level, as a herd of wildebeests or a colony of leaf cutters: we can better secure what we want together than apart. It is thus in the interest of the members that the group succeed, but the cooperation and reciprocity it requires raises the possibility of cheating. Mechanisms must then be found to punish cheating and encourage compliance. Since eusocial insect societies have the same function, encounter the same problems, and apply similar solutions as human political societies, the term justice is no metaphor when used to describe the former. It is the same thing in both cases.
This is enough to confirm natural right in one of its two basic senses. Some basic code of justice is necessary if social cooperation is to occur. Among primate species, equality is not common. Chimpanzees and bonobos both have hierarchical social structures, with some individuals dominant over others. But every member of the group has to be a little better off as a member than he or she would be outside the group. When the dominant male is unwilling to pay even that small a dividend, he expels members (young males) from the group. A harem species like the gorilla follows this model.
Within most primate social groups, hierarchies develop in order to manage competition with a minimum of dangerous friction. A dominant male will get first access to food or a female in estrus without having to fight about it, but subordinate individuals will eventually get a turn. Within all primate social groups, a wide range of behaviors have evolved to facilitate the mediation of conflict and so allow social life to achieve its ends. Dominance and submission displays are a relatively harmless form of combat. Grooming, where one individual combs through the fur of another for parasites, frequently marks and may reinforce a chain rank in the group.21
Jessica Flack and Frans de Waal have argued that many of the primary characteristics of human morality are clearly observed in a number of other species: “cognitive empathy”, “prescriptive social rules”, “moralistic aggression against violators of reciprocity rules”, and “accommodation of conflicting interests through negotiation,” are among these.22 De Waal argues in many of his works that such behaviors suggest a range of moral emotions in animals. As the title of one of his books puts it, some animals are “good natured.”23 If this is so, then at some point in the evolution of animals a set of moral emotions was developed and laid over the autonomous decision sets that constitute moral codes in simpler creatures.
It would be a mistake to assume, prematurely, that the emotions of other primates closely resemble our own. But there is no reason to assume that they are all that different, either. At this point in the game it would be silly to deny that moral emotions in human beings are evolved dispositions, or that such dispositions are designed to serve social goals. There is no group of human beings who do not understand the concept of reciprocity, nor any human society in which righteous indignation does not occasionally arise in response to a failure to reciprocate. Reciprocity is one of those basic moral behaviors that allow individuals to act as partners for the benefit of each and all.24
Of course human beings lay an additional and very rich layer of rules over those that they inherit from their primate ancestors. The scholarship now recognizes it as a serious mistake to set nature and nurture in opposition to one another. Culturally generated (or socially constructed) rules, what the Greek philosopher called nomoi, build upon, refine, and channel natural emotions. It is likely that, just as human beings are born with a natural inclination to listen for and a capacity to learn a specific language, they are born with similar inclinations and capacities to learn moral rules. Human nature and human nurture presuppose one another. This can make it very challenging to tease the two influences apart.
It’s hardly necessary to do so to see that the foundation of human justice is natural justice. The basic rules of justice are observed even within the single cells in an animal’s body, where a home has been made for previously independent creatures with their own DNA. The rights of mitochondria are respected, and the return on that respect is spectacular. Similar rules are observed between cells, and between the insects that make up a superorganism. More complex animals have had to work out their versions of justice, alone with their basic complement of emotions, memories, and rules. Human beings, equipped with logos, have taken up writing new and complex rules on the fly. The foundation of all positive right is clearly natural right, just as Lincoln supposed.
If natural right is confirmed by the science of nature, what about natural rights? To be sure, a ground level requirement of natural justice is that every member of the community profit by part of it. Anything else is mere exploitation. But is there some ground for Jefferson and Lincoln’s belief in a natural equality of rights?
It turns out that in several primate species there are social behaviors designed to control the more dominant members and protect the less or even least dominant. Among chimpanzees there is a general right of possession with regard to food. A chimpanzee is most aggressive toward a fellow who begs or tries to take away his food, and rarely so toward one who securely possesses it. This rule seems to overcome dominance.
When chimps hunt colobus monkeys, the best hunters do not selfishly devour their catch but share it promiscuously. Likewise a dominant individual may climb a tree and cast down food to the other members of his group. One reason for this is to minimize resistance to their status. The same rule is observed among hunter gatherers. The good hunter shares his meat with the tribe. This altruistic act is rewarded with superior status, including, perhaps, more wives. It is binding on the hunter as well as the congregation at dinner.25
Christopher Boehm has argued compellingly that hunter gatherer tribes were remarkably egalitarian, and that powerful mechanisms existed within the tribe precisely to prevent despotism by the most powerful members. This is necessary precisely because human beings are not an innately egalitarian species. Dominance behaviors are a powerful influence. A primary function of moral rules is to suppress deviants, and excessively dominant behavior is recognized in these simple societies as a deviation from right.26 Only with the discovery of agriculture and the rise of civilizations did inequality and despotism become common features of human life. If Boehm is right about our recent ancestors, then modern egalitarianism looks like a return toward standards of justice that were long observed among human beings and that are a better fit with human nature.
But the more important argument in favor of an equality of rights is based the equal moral capacity of all human beings. Some persons are larger, faster, and/or smarter than others. Some are probably born inclined to better or worse behavior, but every human being is equally capable of moral responsibility. If the rules of justice can be written into the brains of ants, they can be grasped by any undamaged person.
There is strong evidence from the field of evolutionary psychology that the moral sense is ubiquitous across cultures, and that it expresses fairly simple, remarkably egalitarian rules. One famous example is the ultimatum game. In this product of game theory, two people are offered a sum of money. The first player can allocate the money any way he wants between himself and his partner. The second player must accept the allocation, or neither gets any money.
Based on simple economic calculation, you would expect the allocator to give up the smallest sum possible, and his partner to accept anything since something is better than nothing. In fact, allocators tend to be fairly generous, most often giving up nearly half the sum. When much less than that if offered the deal is usually refused, at an obvious cost to both players. Righteous indignation is a psychological mechanism that serves, among other things, to enforce rules of justice. The uneasiness of one who is tempted to cheat and the indignation of one who is cheated are innate reactions in most people, and not easily controlled. All human beings are created equal at least in this sense, that everyone is equally capable of understanding the first player’s position and the second player’s response.27
Abraham Lincoln’s doctrine of natural rights, based on his interpretation of the Declaration of Independence, and employed as the basis of his campaign against the extension of slavery, requires three things to be true if it is to be sustained. First, there must be no natural justification for the rule of any set of masters over any set of slaves. Second, natural right must be natural in the sense that it serves natural ends. Finally it must be natural in so far is it is served by natural human inclinations. Lincoln thought common sense adequate to back up all three. He was probably right in a practical sense.
Modern Darwinian biology has brought powerful evidence to bear on this question, and all three requirements of natural right have been largely confirmed. Human beings are by nature self-governing creatures, deserving equal rights because we are equally capable of moral responsibility. We are capable of deliberation on behalf of justice and the common good and we so for the sake of the best possible life; but we do so with existential capacities and according to moral rules that are much older than the human species. The Creator may have been joking when he arranged for Darwin and Lincoln to be born on the same day, but it was a pretty good joke.
Adam Gopnik, Angels and Ages: A Short Book about Darwin, Lincoln, and Modern Life
(New York: Alfred A. Knopf, 2009).
2 Adrian Desmond and James Moore, Darwin’s Sacred Cause (New York: Houghton Mifflin Harcourt, 2009).
3 Paul M. Angle, ed., Created Equal: the Complete Lincoln Douglas Debates of 1858 (Chicago: University of Chicago Press, 1958), 12.
4 Don E. Fehernbacher, ed., Abraham Lincoln: Speeches and Writings 1832-1858 (Library of America, 1989),28-36.
Plato, the Republic
, the Politics
6 Aristotle, the Politics, 1278b6-1279a21.
7 Roy P. Basler, ed. Abraham Lincoln: His Speeches and Writings (Cleveland: World Publishing Company, 1946), 402.
8 Thomas Jefferson, “Declaration of the Causes and Necessities of Taking Up Arms,” in
9 Basler, Abraham Lincoln: His Speeches and Writings, 302.
10 See the Lyceum Speech in Fehernbacher, Abraham Lincoln: 1832-1858, 28-36.
11 Fehernbacher, Abraham Lincoln: 1832-1858, 301-303.
12 This argument is obviously a transcription from Aristotle’s the Politics 1283b9-27.
13 “Eusocial” insect societies display “all of the following three traits: cooperation in the caring for the young; reproductive division of labor…; and an overlap of at least two generations of life stages capable of contributing to colony labor.” Bert Hölldobler and E. O. Wilson, The Superorganism (New York: W. W. Norton, 2009), p. 507.
14 Aristotle, the Politics, 1253a7-9.
15 Bert Hölldobler and E. O. Wilson, The Superorganism, 4.
16 Bert Hölldobler and E. O. Wilson, The Superorganism, 412.
17 Lee Alan Dugatkin, Cheating Monkeys and Citizen Bees: The Nature of Cooperation in Animals and Humans (New York: The Free Press, 1999), 48-54.
18 Lee Alan Dugatkin, Cooperation Among Animals: An Evolutionary Perspective (New York: Oxford University Press, 1999), 149-151.
19 Bert Hölldobler and E. O. Wilson, The Superorganism, 336-355.
20 Marion Hall et al., Behavior and Evolution (Singapore: Springer, 1998), 259-261.
21 Dorothy L. Cheney and Robert M. Seyfarth, Baboon Metaphysics: the Evolution of a Social Mind (Chicago: University of Chicago Press, 2007), 72-74.
22 Jessica C. Flack and Frans B. M. de Waal, “Any Animal Whatever: Darwinian Building Blocks of Morality in Monkeys and Apes,” in Leonard D. Katz, ed., Evolutionary Origins of Morality, (Bowling Green: Imprint Academic, 2000), 22.
Frans De Waal, Good Natured: The Origins of Right and Wrong in Humans and Other Animals
. (Cambridge: Harvard University Press
24 For a discussion of “strong reciprocity,” i.e., a predisposition to cooperate or punish violations of norms of cooperation even when there is no reason to expect some benefit from such behavior, see Herbert Gintis, et al., “Explaining Altruistic Behavior in Humans,” in R.I.M. Dunbar and Louise Barrett, eds., The Oxford Handbook of Evolutionary Psychology (Oxford: Oxford University Press, 2007), 605-619.
25 Sober, Elliot and David Sloan Wilson, Unto Others: The Evolution and Psychology of Unselfish Behavior (Cambridge: Harvard University Press, 1998), p. 142-149; and Flack and de Waal, “Any Animal Whatever, 4-6. For an argument against the view that animals have moral emotions, see Marc Hauser, Wild Minds: What Animals Really Think (New York: Henry Holt, 2000), 211-253. Hauser is more skeptical about animal emotions than I am, but his method of analysis is basically the same as in my argument.
26 Christopher Boehm, “Conflict and the Evolution of Social Control,” in Katz, Evolutionary Origins of Morality, 79-101.
, Anne. “Aggression,” in David M. Buss, ed., The Handbook of Evolutionary Psychology
, (Hoboken: Wiley, 2005), p. 636.