The Aristotelian Biology of Thomistic Natural Law (2)

Eric Johnston's dissertation is a valuable study of how Aristotelian biology supports Thomas Aquinas's account of the natural law of marriage. As Johnston indicates, his dissertation is primarily a historical work that tries to understand Aquinas's position, without judging whether that position is defensible as being simply true. But still, it's clear that Johnston is generally supportive of what Aquinas says, and he so he wants to defend Aquinas as making intellectually respectable arguments.

Any defense of Aquinas's biological reasoning today requires some judgment as to whether it is compatible with modern biological science, assuming that we agree that that science is generally correct. And, indeed, Johnston does suggest that Aquinas's biology is roughly compatible on many major points with modern biology, although he does this only briefly and often only in some footnotes.

I would go farther in that direction than Johnston wants to go, and that's why I disagree with him on four points.

First, Johnston assumes that biological science can study only the purely physical side of human life, and therefore it cannot account for the mental or moral reality of human experience (11, 48, 52, 240). But this is not true either for Aristotelian biology or for modern Darwinian biology. Aristotle's biological writings study not just the physical but also the mental capacities of animals, and it's this biological study of animal cognition that is so important for Aquinas. Darwin continued in this tradition in studying the evolution of the mental and moral capacities of animals. Today, the ethology and neuroscience of animal cognition belong to this Aristotelian tradition of biological psychology. It is true that human beings are unique in ways that make them uniquely capable of moral judgment and symbolic reasoning. But even these humanly unique traits can be understood as products of the emergent evolution of primate cognition.

Johnston observes: "modern biology, viewing the animal from a purely physical perspective, cannot engage the question of ensoulment because it does not engage the question of the soul" (240). But while it is certainly true that modern biologists are unlikely to use the language of "soul" and "ensoulment," they will talk about the biology of cognition and mental states. So, for example, as indicated in some recent posts, primatologists will look for evidence that chimpanzees have a "theory of mind."

My second disagreement is that, while Johnston does occasionally defend the Aristotelian biology of sex differences against the charge of sexist bias (27, 158-159, 233-234, 241), I would go farther in this direction in arguing that Aristotle's embryological explanation of male-female differences is close to what we know today from modern biology. Aristotle understood that the formation of a male embryo depended on the action of testicular secretions in the womb, and that in the absence of these secretions, the embryo develops as a female. Consequently, abnormalities of hormonal masculinatization can result in abnormalities of gender identity. I have laid out my reasoning on this in an article: "A Sociobiological Defense of Aristotle's Sexual Politics," International Political Science Review, 15 (1994): 389-415. Some of this same ground is covered by an article cited by Johnston: Michael Nolan, "The Aristotelian Background to Aquinas's Denial that 'Woman is a Defective Male,'" The Thomist, 64 (2000): 21-69.

My third disagreement is that, unlike Johnston, I think that the ecclesiastical persecution of those studying Aristotelian natural philosophy might have made it necessary for Aquinas to engage in esoteric writing to avoid persecution. Dante hints at this in the DIVINE COMEDY (PARADISO, X.82-148). Siger de Brabant was condemned as an Averroist heretic who taught Aristotelian philosophy without regard for Christian faith. Dante puts him in Heaven, and he has Thomas Aquinas praise him as one who "demonstrated truths that earned him envy." Aquinas introduces himself as "a lamb among the holy flock that Dominic leads on the path where one may fatten well if one does not stray off," thus suggesting that Aquinas hid his support for Siger so as not to stray too openly from the faith of the Dominicans.

One place where Johnston might have seen this is in Aquinas's use of embryology to answer the question (in De Potentia, q. 3, a. 9) of whether the rational soul can be transmitted through semen, or whether it must be infused by God's miraculous creation. Johnston notices that this requires an unusually complicated response by Aquinas (241-59). Aquinas indicates that this question of whether natural embryological development can produce the rational soul of a human being "has been answered in various ways by different people" with different "opinions." One of these "opinions" was that yes, indeed, natural reproduction could produce a child with a rational soul. But then the Church condemned such "opinions" and declared that the rational soul must be specially created by God and then infused into the body of the developing child. "Now to maintain that the soul is made by the generation of the body, is to say that it is not subsistent and consequently that it ceases with the body." This is a heresy, and it was one of the propositions condemned by the Bishop of Paris in 1277. Thus, Aquinas could not openly embrace this without being condemned as a heretic (cf. ST, I, q. 118, a. 2). Aquinas argues in defense of the Church's position--that the rational soul must be specially created by God and infused into the body--but he refers to this as an "opinion," which might make a careful reader wonder whether he is fully and honestly affirming its truth.  For Aquinas, "opinion"--as opposed to "science" or "faith"--is affirming something without firm confidence (ST, I-II, q. 67, a. 3).

Aquinas's argument for this "opinion" is that nature is an instrument in the hand of God, and therefore God can intervene at any time to go beyond what the instrument can do on its own. But if God is able and willing to use nature to create nutritive and sensitive souls, as Aquinas says, then why is He not able and willing to use nature to create rational souls? Although a reader might raise this question, Aquinas cannot openly raise it himself without risking persecution.

This is still an issue today with regard to how far the Catholic Church can go in accepting modern evolutionary science. In 1996, Pope John Paul II appeared to endorse the idea of human evolution by purely natural processes. But he also insisted that while evolutionary science can explain the natural evolution of the human body, the appearance of the rational soul unique to human beings requires a miraculous act of God in the embryological process.

My final point of disagreement with Johnston is in his observation: "His account of the natural law is thoroughly theonomic. Natural law is not a way of discerning the good life in abstraction from God" (296). I agree that any orthodox Christian must believe that all of nature, including natural law, is ultimately part of eternal law as created by God. But it does not follow from this that the power of natural law depends on a belief that it is divinely ordained. If that were so, then there would be no reason for Aquinas to distinguish between natural law and divine law, and thus natural law could not be comprehensible as purely natural without supernatural revelation. If natural law corresponds to the natural biological inclinations of the human animal, then why doesn't the natural power of those inclinations hold true for us regardless of our religious beliefs?

To go back to the example of marriage, all human beings should be able to grasp the natural truth that human beings as sexual animals are naturally directed to parental care and spousal love. And while belief in some theological view of marriage might reinforce those natural inclinations, the natural inclinations can stand on their own natural ground even without religious belief. By contrast, the religious view of marriage as a sacrament symbolizing the marriage of Christ and His Church depends upon faith in revelation rather than reasoning about nature.

In addition to my recent posts, some of my older posts on related topics can be found here, here, here, here., and here.

The Aristotelian Biology of Thomistic Natural Law

In some of my recent posts, I have argued that Thomas Aquinas's teaching on natural law is rooted in Aristotle's biology, that this is particularly clear in Aquinas's biological account of the natural law of sex, marriage, and parental care, and that much of this biological reasoning for natural law can be confirmed by modern Darwinian biology.

I must admit, however, that I have not done a thorough study of how Aquinas uses Aristotle's biology in all of his writing. So I was pleased to discover a dissertation that studies how Aquinas uses Aristotle's biology in his account of marriage. Eric M. Johnston wrote a dissertation in 2009 for his Ph.D. in theology at the Catholic University of America, the title of which is "The Role of Aristotelian Biology in Thomas Aquinas's Theology of Marriage." Johnston is now a professor of theology at Seton Hall University. His dissertation is a wonderfully insightful study of all the places in Aquinas's writing where he speaks about marriage, sexuality, and parenthood, and he shows how Aristotle's biological comparisons of human beings and other animals are used by Aquinas to support his understanding of sexual mating and parental care. Johnston's general conclusion is that "Thomas is able to account for all the main Catholic doctrines on marriage through parallels between human and animal procreation" (44).

I agree with Johnston on most of the points he makes. But I disagree on some points.

I agree with the core of Johnston's dissertation, which is to show how Aquinas carefully employed Aristotle's biological writings--especially, The Generation of Animals and The History of Animals--in using animal biology to explain human sexuality, marriage, and parenting. He shows that even when Aquinas does not directly cite Aristotle, Aquinas often uses examples from Aristotle's biological observations.

For example, one of the most important Biblical texts for the Christian doctrines about marriage is the seventh chapter of Paul's First Corinthians. Paul begins this chapter by writing:

Now concerning the matters about which you wrote. It is well for a man not to touch a woman. But because of the temptation to immorality, each man should has his own wife, and each woman her own husband. The husband should give to his wife her conjugal rights, and likewise the wife to her husband. For the wife does not rule over her own body, but the husband does; likewise the husband does not rule over his own body, but the wife does. Do not refuse one another except perhaps by agreement for a season, that you may devote yourselves to prayer; but then come together again, lest Satan tempt you through lack of self-control. I say this by way of concession, not command. I wish that all were as I myself am. But each has his own special gift from God, one of one kind and one of another. To the unmarried and the widows I say that it is well from them to remain single as I do. But if they cannot exercise self-control, they should marry. For it is better to marry than to be aflame with passion. (I Cor 7:1-9)

In Aquinas's Commentary on First Corinthians, one of the remarkable features of his commentary on this passage is that he introduces biological comparisons with other animals (from Aristotle's biological writings), although Paul says nothing about this. Aquinas writes:

Natural reason teaches that man use the act of generation according as it is suitable for generation and education of children. But in brute animals, it is found that in certain species the female alone is not sufficient for the training of the offspring, but the male takes care of the offspring with the female. For this, it is required that the male recognize its offspring. Therefore, in all such animals, as doves, pigeons, and the like, solicitude for the training of offspring is inspired by nature. Wherefore, in such animals, intercourse is not random and indiscriminate, but a definite male is joined to a definite female, not one to another promiscuously, as happens in dogs and such animals, in which the female alone takes care of the offspring. But above all in the human species, the male is required for the education of the offspring, which are attended to not only regarding bodily nourishment, but to a greater degree regarding the nourishment of the soul, as it says in Hebrews (12:9): "We have had earthly fathers to discipline us and we respected them." And consequently, natural reason dictates that in the human species intercourse is not random and uncertain, but is by a definite man to a definite female, who in fact made the arrangement through the law of matrimony.

Thus, therefore, matrimony has three goods. The first is that it is a function of nature in the sense that it is ordered to the production and education of offspring; and this good is the good of offspring. The second good is that it is a remedy for desire, which is restricted to a definite person; and this good is called fidelity, which a man preserves toward his wife, by not going to another woman, and similarly the wife toward the husband. The third good is called the sacrament, inasmuch as it signifies the union of Christ and the Church, as it says in Ephesians (5:32): "This mystery is a profound one, and I am saying that it refers to Christ and the Church."

That comparison of human beings with other sexually reproducing animals states the main principles of Aquinas's teaching on sex, marriage, and familial bonding. Like other animals, human beings are driven by a powerful natural desire for sexual mating. Like other animals whose offspring cannot survive or flourish without parental care, and for whom the care of both parents is often necessary, there is a natural need for long-lasting bonding between the mother and the father for the care of the young. But the parental attachment of the father depends on his confidence that he's caring for his own children rather than the children of another man. This must be so, because love of children is an extension of our self-love, so that we love our children as our own. Even adoption requires some such special attachment so that our adopted children seem to be our own. For human children, parental care includes not just bringing children into existence but also feeding them and educating them, because children need a long period of social learning before they can live as mature young adults.

As thus rooted in human biological nature, human marriage has two natural goods--the good of parental care and the good of spousal love.

For Catholic Christians, there is a third good of marriage that is supernatural--the good of marriage as a sacrament of the Church in symbolizing the supernatural mystery of Christ's marriage to the Church as His bride.

It seems, then, that while the first two goods are matters of natural law as rooted in the biological nature of human beings as sexually reproducing animals, the third good surpasses natural law because to recognize marriage as a sacrament, we need the divinely revealed law of the Bible.

But then we might wonder how far Thomas's Aristotelian biology goes in supporting the Thomistic natural law teaching as grounded in natural experience and reasoning without need for divine revelation. We might also wonder how far modern biological science could support this teaching. On both points, I go farther than Johnston wants to go. I'll explain this in my next post.

Tomasello on the Chimpanzee Theory of Mind and Social Ontology

In an email message responding to my previous post, Michael Tomasello has observed that it's not quite true that his research produces mostly negative findings--stressing what chimps can't do. For example, to the question of whether chimps have a theory of mind, Tomasello's answer is that in many respects they do, while in some respects they don't; and this shows how chimps are both similar to human beings and yet different.

Thus Tomasello's negative conclusions about the limits of chimpanzee cognition are in the service of a positive theory of how human uniqueness evolved.

Some years ago, Tomasello concluded that chimps and other non-human primates have no capacity for understanding the psychological states of other individuals. But more recently, he has decided that new experimental research shows that he was wrong, and that chimps can understand that others perceive and know things and have goals or intentions. For instance, experiments in which chimps are competing for food show that they think about what their competitor can and cannot see, hear, or know. In this sense, chimps do have a theory of mind.

And yet, in another sense, they don't, Tomasello argues, because there is no experimental evidence that chimpanzees understand false beliefs--that other individuals can be not only informed or uninformed but misinformed. By comparison, children as young as 4 years old--and perhaps even younger--do understand that individuals can have false beliefs.

Here's the abstract for one of his articles on this point ("A Nonverbal False Belief Task"):

A nonverbal task of false belief understanding was given to 4- and 5-year-old children (N=28) and to two species of great ape: chimpanzees and orangutans (N=7). The task was embedded in a series of finding games in which an adult (the hider) hid a reward in one of two identical containers, and another adult (the communicator) observed the hiding process and attempted to help the participant by placing a marker on the container that she believed to hold the reward. An initial series of control trials ensured that participants were able to use the marker to locate the reward, follow the reward in both visible and invisible displacements, and ignore the marker when they knew it to be incorrect. In the crucial false belief trials, the communicator watched the hiding process and then left the area, at which time the hider switched the locations of the containers. When the communicator returned, she marked the container at the location where she had seen the reward hidden, when was incorrect. The hider then gave the subject the opportunity to find the sticker. Successful performance required participants to reason as follows: the communicator placed the marker where she saw the reward hidden; the container that was at that location is now at the other location; so the reward is at the other location. Children were also given a verbal false belief task in the context of this same hiding game. The two main results of the study were: (1) children's performance on the verbal and nonverbal false belief tasks were highly correlated (and both fit very closely with age norms from previous studies), and (2) no ape succeeded in the nonverbal false belief task even though they succeeded in all of the control trials indicating mastery of the general task demands.

This research is part of Tomasello's larger research project for understanding the evolutionary psychology of social ontology. As indicated by John Searle and other philosophers, we live in two worlds--a physical reality that is true independently of our subjective awareness and a social reality that depends on our subjective awareness. So, for example, a piece of paper money exists physically as a piece of paper regardless of what we think about it, but its value as money depends on our subjective social agreement. All of our social practices and institutions--money, property rights, government, and so on--are like this. All social animals seem to have some cognitive capacities that allow them to create their social worlds. But human beings seem to be unique in having cognitive capacities that allow them to create social worlds that are far more complex, extensive, and flexible than is the case for other social animals. Any evolutionary science of social cooperation must explain this.

Through his experiments comparing non-human primates and children, Tomasello concludes that while chimps are capable of social coordination, which requires that individuals respond to each other's behavior--as, for example, when chimps engage in group hunting or warfare--they do not show the collaboration through joint intentions based on coordinated plans that arises among young children.

The uniqueness of human institutional ontology is evident in how human beings use language to construct social institutions. But Tomasello thinks that the primary entrance into human social reality is through games of pretend play that display their basic structure among 2-year old children. Through games of pretense, children create social activities through agreement with others on the rules of the game, which shows the crucial step towards human social ontology, a step not taken by chimps. (Of course, to pursue this further, we would have to ask how this is different from the play behavior of other primates.)

REFERENCES
Josep Call and Michael Tomasello, "A Nonverbal False Belief Task: The Performance of Children and Great Apes," Child Development, 70 (March/April 1999): 381-395.

Josep Call and Michael Tomasello, "Does the Chimpanzee Have a Theory of Mind? 30 Years Later," Trends in Cognitive Sciences 12 (2008): 187-192.

Hannes Rakoczy and Michael Tomasello, "The Ontogeny of Social Ontology: Steps to Shared Intentionality and Status Functions," in S. L. Tsohatzidis, ed., Intentional Acts and Institutional Facts: Essays on John Searle's Social Ontology (Dordrecht, The Netherlands: Springer, 2010), 113-137.

More on the de Waal/Tomasello Debate in Primate Research

In my previous post, I briefly surveyed some of the issues in the debate between Frans de Waal and Michael Tomasello in comparing the social intelligence of human beings and other primates--with de Waal stressing the similarities and Tomasello stressing the differences.

I have received a few email messages from folks who think I haven't given enough attention to the flaws in Tomasello's research, which point to at least three major problems.

The first problem is that the results of Tomasello's experiments are mostly negative in emphasizing what chimpanzees and other apes cannot do by contrast with human beings. Such negative results leave us wondering whether this comes from some failing in the methodology that prevented the apes from showing their true abilities. Once people like de Waal try out a new methodology that produces positive results for the apes, it's not clear that Tomasello's research with negative results has much interest.

The second problem is that Tomasello's experiments comparing chimpanzees and human infants are dubious because they are conducted mostly with human experimenters, which creates a disadvantage for the chimps. It is easier for human infants to demonstrate their social skills when dealing with a human experimenter than it is for chimps to do this when dealing with a member of another species. We should expect that the full complexity of chimp social intelligence will be manifested only within chimp groups.

The third problem is that Tomasello's negative results often contradict what researchers are seeing among chimps in the wild. So, for example, de Waal's latest experiments showing chimp prosocial behavior conforms to what researchers like Andrew Whiten and Christophe Boesch have already seen among chimps in the wild in Africa.

The fundamental difficulty running through all of this is that in comparing human beings and other apes, we need to explain both the similarities and the differences.

Tomasello observes:

. . . I am among those who are regularly accused of "raising the bar" on chimpanzees; that is, as soon as we discover that something we thought was a human-chimpanzee difference turns out not to be (e.g., understanding goals), we then posit something else as different and uniquely human (e.g., social imitation, normativity). But this raising of the bar results from the simple fact that there are observable differences between chimpanzee and human societies in terms of such things as complex technologies, social institutions, and symbol systems, and those most be explained. If some hypothesis about these differences is wrong, then it is rightfully consigned to the trash heap. But then we must come up with some new hypothesis to explain the difference--and there is a difference.

("Postscript: Chimpanzee Culture, 2009," in Laland and Galef, eds., The Question of Animal Culture, 220)

Despite their apparent disagreements, De Waal ultimately has to agree with Tomasello that we must explain the uniqueness of human beings as well as their continuity with other apes. One can see this in what de Waal says about the evolution of morality in Primates and Philosophers. He refers to his experiments on "inequity aversion" among monkeys as showing "a sense of social regularity" or "monkey fairness" (44-45). But then he concedes that this falls short of the full human sense of morality:

Before we speak of "fairness" in this context it is good to point out a difference between this and human fairness, though. A full-blown sense of fairness would entail that the "rich" monkey share with the "poor" one, as she should feel she is getting excessive compensation. Such behavior would betray interest in a higher principle of fairness, one that Westermarck . . . called "disinterested," hence a truly moral notion. This is not the sort of reaction our monkeys showed, though: their sense of fairness, if we call it that, was rather egocentric. They showed an expectation about how they themselves should be treated, not about how everybody around them should be treated. At the same time, it cannot be denied that the full-blown sense of fairness must have started someplace and that the self is the logical place to look for its origin. Once the egocentric form exists, it can be expanded to include others. (48-49; cf. 20, 22, 54-55, 77, 168, 172)

So even as he stresses the continuity of human beings and other primates, de Waal recognizes the uniqueness of the human sense of fairness, which is based on the human capacity for abstract social cognition that extends care for oneself to care for an expanding circle of others. He says that "this rather abstract yet still egocentric concern about he quality of life in a community is what underpins the 'impartial' and 'disinterested' perspective" (172).

To me, this sounds a lot like what Tomasello is saying when he stresses the uniqueness of the human capacity for "shared intentionality," which supports the normative rules and customs of human social institutions, and thus going beyond the behavioral traditions of animal cultures.

No doubt, some of these issues will go into the next version of my "Primate Politics" course at NIU.

The de Waal/Tomasello Debate in Primate Studies

As hard as it is to read the minds of our fellow human beings, it is even harder to read the minds of other animals.

Aristotle's biological works are full of observations about animal minds that qualify him as the first animal psychologist. His general conclusion was that there were traces of almost every human mental ability in other animals, which included emotions, parental care, social learning, communication, imagination, practical judgment, and even something close to intellect. He argued that some animals were capable of voluntary action like that of human children, although they lacked the capacity for deliberate choice that arises in human adults. Some animals are solitary and others gregarious. Of the gregarious animals, some are political. Some of the political animals have leaders. The distinguishing characteristic of the political animals is that they cooperate for some common work or function (koinon ergon). Humans, bees, ants, wasps, and cranes are all political animals in this sense (HA, 488a7-14).

So while human beings are not the only political animals, they are the most political animals, because through speech or reason (logos), they share their conceptions of the advantageous, the just, and the good (Pol, 1253a1-18). Through speech, human beings cooperate for shared ends in ways that are more complex, more flexible, and more extensive that is possible for other political animals. Through speech, human beings can deliberate about the "common advantage" (koinon sumpheron) as the criterion of justice (Rh, 1362a15-63b5). A just political community can be judged to be one that serves the common advantage of all its members, as contrasted with an unjust political community that serves only the private advantage of its ruling group (NE, 1160a13-14; Pol, 1279a17-19).

Aristotle's comparative animal psychology includes the observation that monkeys and apes belong to intermediate species close to human beings in that they "share in the nature of both a human being and the quadrupeds" (HA, 502a16). From his anatomical comparisons, which included dissections of monkeys and apes, he concluded that in their feet, legs, hands, face, teeth, and internal parts, the apes are humanlike (HA 502a17-b27; PA, 689b1-35).

And yet, in relying on direct observations of animal behavior and anatomical dissection, Aristotle, like any animal psychologist, had no direct access to the animal mind. With human beings, he had the data of speech, and thus he could study human politics through the study of political rhetoric in which human beings debate their opinions about political life. Other animals communicate in other ways, but this animal communication is often not as rich as human speech, although Aristotle observed the waggle dance of bees, which we now know to be a remarkably complex form of abstract communication.

The fundamental problem is that the social reality of animal life--including human life--is a mental construction of the animal mind that goes beyond the physical reality of the directly observable world. To understand that mental construction of social reality, we have to draw from our inward subjective experience of our minds and our intersubjective world of symbolism. From our observation of animal behavior, we can project some of our mental experience onto them, but we can never be sure how accurate this is.

We have to assume, as Aquinas said, that "the internal passions of animals can be gathered from their outward movements" (ST, I-II, q. 34, a. 4). But then, as Darwin observed in The Descent of Man, in trying to understand the evolution of human mental abilities from the mental powers of our animal ancestors, we face "the impossibility of judging what passes through the mind of an animal" (Penguin ed., 105).

Over the past hundred years, we have had more systematic study of primate behavior and cognition than was done previously. And over the last forty years, we have seen some methodologically sophisticated studies of primates both in the wild and in captivity, and the captive studies have included controlled, and often ingenious, experimentation. But with all of this primate research, we still face the same problem: primate social reality is a construction of animal minds, and judging what passes through those minds is always speculative and uncertain.

Consider, for example, the many news reports this week--in the New York Times and elsewhere--of new experiments that appear to show chimpanzee generosity. Frans de Waal and his colleagues at Emory University claim to show "spontaneous prosocial choice by chimpanzees." Experiments by other groups suggest that chimpanzees are not very helpful to one another, although observations of chimpanzees in the wild suggest the opposite. De Waal has trained his chimpanzees at the Yerkes National Primate Research Center to exchange tokens for food. In this experiment, chimpanzees were paired up and placed in adjoining cages. One chimp could choose a token from a bucket, with tokens of two different colors. One color would exchange for food for oneself but not for the other chimp. The other color would exchange for food for oneself and for the other chimp. In a majority of cases, the chimp would choose the generous option.

Notice the odd features of this experiment. The participants were seven adult female chimps. We must wonder how much we can conclude from the behavior of seven individuals. We must also wonder why only females were tested, particularly since much of the seemingly cooperative behavior among chimps in the wild is male behavior--such as group hunting and warfare. We might question how much generosity we really see here. The report is that the generous tendency for each individual chimp ranged from 52.9% to 66.7%. That suggests that for some of these individuals the choice of tokens was almost random. And even those showing the more generous tendency are not bearing any costs in their generosity.

As indicated in the New York Times article, this research report has been criticized by Michael Tomasello, Co-Director of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany. Anyone who follows this kind of research knows that Tomasello and de Waal have been on opposite sides of a debate for many years. Most recently, Tomasello and his colleagues have published a study in Nature arguing that "collaboration encourages equal sharing in children but not in chimpanzees." They show that children around the age of three show equitable distribution of resources with those engaged in collaborative activities, but chimps do not exhibit such equal sharing with collaborative partners. They offer this as evidence for a general theory of human evolution: the uniquely human propensity for social norms of fairness and equity arose among human ancestors who shared resources after collaborative foraging, and the ancient evolutionary propensity arises early in the development of children as an evolutionarily natural trait.

De Waal and Tomasello agree in general that human nature can be explained as a product of evolutionary primate history, so that human beings are similar to their closest living relatives--chimpanzees and bonobos--but also quite different in humanly unique ways. And yet de Waal and Tomasello disagree in their emphasis--de Waal emphasizing the similarities, Tomasello emphasizing the differences--a disagreement that runs through much of the primate research.

This disagreement was evident a few years ago when de Waal and his colleague Sarah Brosnan gained wide publicity for a report in 2003 entitled "Monkeys Reject Unequal Pay," which seemed to show that capuchin monkeys had a "sense of fairness." Having been trained to exchange tokens for food, the monkeys seemed to be engaged in economic exchange, which is why this kind of research has gained attention from economists. In an experiment to test for "inequity aversion," monkeys who offered a token for food would receive either a slice of cucumber or a grape, and the monkeys clearly favored the grape as more desirable. If one monkey got a slice of cucumber, while seeing that another monkey nearby got a grape, the monkey apparently protested against this, either by refusing to exhange the tokens or by throwing away the cucumber. It seemed as though the monkey was protesting "unequal pay."

But again we might wonder about some of the features of this research. The report was based on the behavior of only five females. Apparently, males had not shown "inequity aversion." We have to wonder then how far we can go in drawing general conclusions from this experiment.

Moreover, as some critics noticed, it was possible that the monkeys weren't showing "inequity aversion" but only frustrated expectations. If a monkey receives a cucumber slice, while noticing that grapes are available, she might feel frustration at not getting the more desirable food, but this would have nothing to do with "unequal pay." Other critics suggested that a monkey perceiving inequity in the distribution of food would want more cucumber slices, not less, to compensate for the inequity.

We might also ask whether these monkeys were really showing a sense of fairness. Even if we are persuaded that the monkey receiving the less favored food was showing indignation in protesting the inequity from the other monkey getting the more favored food, there is no evidence that the monkey getting the unfair advantage felt any guilt. If the monkeys receiving grapes were to throw away their grapes to show sympathy for those receiving only cucumbers, that would be a far more impressive display of a sense of justice.

A few years later, de Waal and Brosnan tried to answer some of these criticisms with new experiments using chimpanzees. They reported that chimps also showed inequity aversion, although chimps in close social relationships were more tolerant of inequity. And yet, once again, Tomasello and other critics pointed out weaknesses in this report. For example, of the 20 individuals studied, 14 refused inequitable exchanges in less than 2% of the trials, which is not very impressive.

Tomasello and his colleagues did a study of their own with 7 orangutans, 6 gorillas, 4 bonobos, and 13 chimpanzees in which the behavior seemed to show that there was no inequity aversion, and thus contradicting de Waal and Brosnan's research.

Some of the details in this debate are surveyed in an article by Kenneth Krause for eSkeptic.

As compared with what de Waal does, Tomasello's research is more interesting in that he performs similar experiments with chimpanzees and young children to see how and at what age the children surpass the chimpanzees. This allows him to argue that the early development of human children replicates human evolutionary history: we see the children starting out with chimpanzee-like abilities but then quickly moving to the uniquely human capabilities that arose early in human evolution. In this way, ontogeny might recapitulate phylogeny.

Some good videos of this research with both chimpanzees and children can be found here. There is also a good PBS Nova video on this and related research by Tomasello and others.

Tomasello's work is embedded within a general social theory of cooperation, which is well summarized in his book Why We Cooperate (MIT Press, 2009). One can see the influence on Tomasello of John Searle's The Construction of Social Reality (Free Press, 1995). Searle argues that we need to understand how social reality differs from physical reality, because social reality is a construction of the mind through the "collective intentionality" of "we consciousness" as opposed to the "I intentionality" of "I consciousness." In social life, we collaborate with one another as we create institutional practices in acting intentionally for shared goals. We thus create "institutional facts" that are just as real as "brute facts" or physical facts, although these institutional realities depend on the work of our minds, and they are not directly observable the way physical reality is directly observable. Tomasello picks up this idea in arguing that human beings are unique in their capacity for "shared intentionality," which allows human beings through their symbolic capacities to engage in cultural niche construction in ways that far surpass chimpanzees and other primates.

What Tomasello is doing is that he's exploring in experimental ways the evolutionary basis for what Aristotle and Aquinas saw--that we are similar to other social and political animals, and yet we are unique in our capacity to use our conceptual and linguistic abilities to create social worlds of shared intentionality that go beyond anything seen in the rest of the animal world.

Tomasello's comparative studies of chimpanzees and children follows in the tradition of Darwin, who methodically studied one of his infant children and compared the child with monkeys and apes to see when the child showed the moral sense that Darwin thought was uniquely human.

If you really want to probe into de Waal's mind, you'll have to go to the video of his interview on "The Colbert Report."

I will be writing more posts this month on the de Waal/Tomasello debate.

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

REFERENCES
Brauer, Juliane, Josep Call, and Michael Tomasello, "Are Apes Really Inequity Averse?" Proceedings of the Royal Society B 273 (2006): 3123-3128.

Brosnan, Sarah F., and Frans de Waal, "Monkeys Reject Unequal Pay," Nature 425 (18 September 2003): 297-99.

Brosnan, Sarah F., Hillary C. Schiff, and Frans de Waal, "Tolerance for Inequity May Increase with Social Closeness in Chimpanzees," Proceedings of the Royal Society B, 272 (2005): 253-58.

Hamann, Katharina, Felix Warneken, Julia Greenberg, and Michael Tomasello, "Collaboration Encourages Equal Sharing in Children But Not in Chimpanzees," Nature, early online publication, July, 2011.

Horner, Victoria, J. Devyn Carter, Malini Suchak, and Frans de Waal, "Spontaneous Prosocial Choice by Chimpanzees," Proceedings of the National Academy of Sciences, early edition, August, 2011.

Thomistic Natural Law as Darwinian Natural Right: An APSA Paper

On September 1, at 2:00 pm, I will be on a panel ("Biology and Rights") at the 2011 Meetings of the American Political Science Association in Seattle.

My paper is "Thomistic Natural Law as Darwinian Natural Right: Replies to Critics." It can be downloaded.

Some of the material in this paper has been pulled from various posts on this blog.

Under the title "What Nature Has Taught All Animals," I summarize some of the common ground between Thomistic natural law and Darwinian natural right.

I then reply to six objections that have been raised by my critics:

(1) It is said that I fail to see that natural law depends on a divine lawgiver as its source.

(2) Darwinian science denies the natural teleology that is required for natural law.

(3) Darwinian science denies the reality of species as the ground of natural law.

(4) Darwinian natural right denies human freedom by denying the freedom of reason in ruling over the human desires or emotions.

(5) Darwinian explanations of human nature ignore the importance of culture and habituation in shaping human character.

(6) Darwinian naturalism is self-defeating, because in denying that the human mind was created in God's image, and asserting that the mind arose from a mindless process of evolution, it gives us no reason to trust our mental capacity for true beliefs.

My general claim is that by rooting natural law in a scientific conception of human nature, and by avoiding the contradictions that arise from Thomas Aquinas's occasional efforts to elevate revelation over reason, Darwinian natural right is the natural fulfillment of Thomistic natural law.

Mind Is Not the Only Possible First Cause of All Things: Hume, Darwin, and Strauss

The most common objection to my arguments for Darwinian natural right is that Darwinian science fails to see that the only possible first cause of natural order--including natural moral order--is divine Mind. So, for example, Francis Beckwith criticizes me for not recognizing that "natural law and our human nature have their source in Mind." This reasoning that the apparently designed order in the world points to a cosmic Intelligent Designer has a long tradition--from Plato's Laws to Aquinas's natural theology to the proponents of "intelligent design theory" at the Discovery Institute.

I agree that this is one possible explanation for the uncaused cause of all natural order. I agree that this satisfies our natural desire for religious understanding by appealing to our evolved instinct for projecting the human mind onto the world. But affirming this possibility as true is an act of religious faith, not of rational demonstration. This religious belief in an intelligently designed cosmos can be neither proven nor refuted by natural reason.

It is possible, therefore, for the theistic believer to be a theistic evolutionist, believing that the Intelligent Designer has used the natural evolutionary process to carry out His plan. C. S. Lewis, Alvin Plantinga, and many other theists have taken this position. But, again, this is an act of faith rather than reason.

Affirming the existence of a divine Mind as the intelligent designer of cosmic order cannot be proven by reason, because this is only one possibility among many that we can draw from our natural experience of order. Since there are many different principles of order that we might use to explain the cosmic order of nature, and since there is no demonstrative proof that one principle is better than all the others, we are left in a state of skeptical doubt.

As I have indicated in some recent posts, the supposed proof for the existence of a divine Mind depends on an anthropomorphic analogy of mental agency, which assumes that the natural order of the cosmos is an artifact that points to the mental agency of a divine artisan. Leo Strauss rejected this analogy in suggesting other possibilities: "One realizes the possibility that the first things originate all other things in a manner fundamentally different from all origination by way of forethought. The assertion that all visible things have been produced by thinking beings or that there are any superhuman thinking beings requires henceforth a demonstration, a demonstration that starts from what all can see now" (NRH, 89).

In this passage, Strauss doesn't explain what this alternative possibility is. But in his 1948 lecture on "Reason and Revelation," he did identify Darwin's evolutionary science as an alternative to divine creationism, and thus he put Darwinism on the side of reason against revelation.

In Cicero's De Natura Deorum, Cotta suggests various alternatives to Platonic and Stoic intelligent-design cosmology. In Hume's Dialogues Concerning Natural Religion, Philo lays out more clearly what these alternative possibilities might be, and he suggests the possibility of evolution by natural selection.

In the Dialogues (part 7), Philo argues that any attempt to explain the order of the universe depends on reasoning by analogy, where we look for some likeness between the order of the universe and the order of those things that we know by experience. Thus we must project the order of some small part of nature onto the whole of the natural universe.

Philo suggests that there are at least four such principles--reason, vegetation, instinct, and generation. The natural theology of intelligent design rests on the principle of reason as the source of order. From our experience with human mental agency in designing things and carrying out those designs, we might infer that the whole universe is the design of a mental agent. But we might just as easily employ the principles of vegetation, instinct, or generation. Plants grow from seeds and develop into intricately complex organisms. Animals engage in complex behaviors that manifest instinct. Animals generate offspring that grow into fully formed adults. In each case, we see principles of natural order that don't require reason. In fact, reason itself seems to be produced by animal generation, so that generation is prior to reason.

Philo observes:

To say that all this order in animals and vegetables proceeds ultimately from design is begging the question; nor can that great point be ascertained other wise than by proving a priori, both that order is, from its nature, inseparably attached to thought, and that it can never, of itself, or from original unknown principles, belong to matter.

It all depends on judging likenesses:

The world, say I, resembles an animal, therefore it is an animal, therefore it arose from generation. The steps, I confess, are wide; yet there is some small appearance of analogy in each step. The world, says Cleanthes, resembles a machine, therefore it is a machine, therefore it arose from design. The steps are here equally wide, and the analogy less striking.

Or maybe the world was spun out by a cosmic spider:

The Brahmins assert that the world arose from an infinite spider, who spun this whole complicated mass from his bowels, and annihilates afterwards the whole or any part of it, by absorbing it again, and resolving it into his own essence. Here is a species of cosmology, which appears to us ridiculous; because a spider is a little contemptible animal whose operations we are never likely to take for a model of the whole universe. But still here is a new species of analogy, even in our globe. And were there a planet wholly inhabited by spiders (which is very possible), this inference would there appear as natural and irrefragable as that which in our planet ascribes the origin of all things to design and intelligence, as explained by Cleanthes. Why an orderly system may not be spun from the belly as well as from the brain, it will be difficult for him to give a satisfactory reason.

Later (in part 8), Philo comes close to formulating Darwin's theory of evolution:

It is in vain, therefore, to insist upon the uses of the parts in animals or vegetables and their curious adjustment to each other. I would fain know how an animal could subsist, unless its parts were so adjusted? Do we not find, that it immediately perishes whenever this adjustment ceases, and that its matter corrupting tries some new form. It happens, indeed, that the parts of the world are so well adjusted, that some regular form immediately lays claim to this corrupted matter: and if it were not so, could the world subsist? Must it not dissolve as well as the animal, and pass through new positions and situations; till in a great, but finite succession, it falls at last into the present or some other order?

It seems that what Darwin later developed in the theory of evolution specified what Hume considered a theoretical possibility.

And yet both Hume and Darwin (and Hume's character Philo) indicated that there was some plausibility to the design argument as based on the analogy to the human mind. In the Treatise on Human Nature, Hume declared: "The order of the universe proves an omnipotent mind." In the Natural History of Religion and the Dialogues, Hume acknowledges the power of the argument from design in supporting "true religion" or "philosophical theism," even as he exposes the weaknesses in such reasoning by anthropomorphic analogy.

Similarly, in his Autobiography, Darwin said that he often felt compelled "to look to a First Cause having an intelligent mind in some degree analogous to that of man; and I deserve to be called a Theist." But one page later, he concludes: "The mystery of the beginning of all things is insoluble by us; and I for one must be content to remain an Agnostic." Then, on the next page, he says that by the end of his life, he was governed by "scepticism or rationalism."

Does the powerful appeal of the argument from intelligent design show the power of our evolved natural instinct for religious understanding, which shows the working of what Justin Barrett and Jesse Bering identify as our "hyperactive agency detection device"?

In any case, Hume, Darwin, and Strauss show us that we can challenge that religious instinct by showing that the argument from intelligent design rests on an indemonstrable analogy. The natural desire for religious understanding is checked by the natural desire for intellectual understanding. We must choose between revelation and reason.

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