Vol 443|26 October 2006 AUTUMN BOOKS The Chomsky of morality? A view of morality as the product of an innate mental faculty — rather like language.

Moral Minds: How Nature Designed Our a scene (“Omigod, he’s having GEE Universal Sense of Right and Wrong sex with a chicken!”) and then MA

converge upon a moral judge- JOE by Marc D. Hauser Y B Ecco: 2006. 512 pp. $27.95 ment (“There should be a law against that.”). Paul Bloom & Izzat Jarudi TIONS A different concern is that TRA

In Moral Minds, Marc Hauser makes an auda- languages are combinatorial US cious claim about moral thought. He argues symbolic systems. An English ILL that morality is best understood in much speaker, for example, knows the same way as Noam Chomsky described perhaps hundreds of thou- language: as the product of an innate and sands of words, and also knows universal mental faculty. For Hauser, moral principles of syntax that dictate intuition is not the product of culture and how these words combine with education, nor is it the result of rational and one another to form sentences. deliberative thought, nor does it reduce to the There are other combinatorial workings of the emotions. Instead, it is human systems in human cognition, nature to unconsciously and automatically such as number and music, evaluate the moral status of human actions: but it’s not clear that moral- to judge them as right or wrong, allowed or ity is one of them. Even if it is forbidden, optional or obligatory. distinct from emotion, moral As Hauser is careful to point out, he is not knowledge might be better the first to make the leap from a chomskyan characterized as a small list of theory of language to a chomskyan theory of evolved rules, perhaps simple morality: this analogy was proposed by the (such as a default prohibition political philosopher John Rawls, the legal against intentional harm), per- scholar John Mikhail of Georgetown Uni- haps complex (such as some versity in Washington DC, and by Chomsky version of the doctrine of himself. But Moral Minds is the first detailed double effect), but still very exploration of this idea. It is a trade book, different in character from highly accessible to a general audience and linguistic knowledge. drawing on diverse examples from literature, This combinatorial issue popular culture and history. But it is also a neuroscientific studies that support the exist- becomes relevant when it comes to differences deeply significant intellectual contribution: ence of innate principles of moral thought. in morality between people. The approach everything that’s done in the new science of In other regards, however, language seems developed by Chomsky explains differences in moral psychology in the coming years is going very different from morality. For one thing, human languages in terms of the parametric to be a response to this important and enjoy- linguistic knowledge is distinct from emotion. variation of universal principles. All languages able work. You might be disgusted or outraged by what have verb phrases, for instance, but in some of Certain deep parallels between language somebody says, but the principles that make them, such as English, the object follows the and morality make Hauser’s proposal worth sense of sentences are themselves entirely cold- verb, whereas in other languages the object taking seriously. Chomsky has long observed blooded. Your eyes do not well with tears as goes first. Hauser makes an excellent case that that language is a system of knowledge, but you unconsciously determine the structural the variation in moral systems is constrained in what we know (competence) is different from geometry of a verb phrase. By contrast — and interesting ways, but he provides no evidence how we use this knowledge in everyday life Hauser wrestles with this throughout Moral for parametric variation of the linguistic sort. (performance). Linguistic competence is also Minds — even those who accept that some Instead, as the cultural anthropologist Richard unconscious: every English speaker knows that moral capacity is innate often see it as inextri- Shweder of the University of Chicago, Illinois, something is wrong with the sentence “John cably linked to emotion. Perhaps the universal and others have argued, you get a difference seems sleeping,” but only experts understand core of morality is a set of emotional responses in emphasis: all cultures value both purity and why. Similarly, moral intuitions are imper- — disgust, shame, sympathy, guilt and so on fairness, for instance, but some emphasize the fectly linked to action — you can know the — that are triggered by certain situations. former and others the latter. In addition, there right thing to do but choose not to do it — and This hypothesis is supported by clear demon- can be dramatic variation in morality within an only experts can articulate adequate reasons strations that, at least in some circumstances, individual culture. As Hauser notes, for exam- for common-sense moral judgements. Finally, emotion precedes intuition. The psychologist ple, the culture of honour in countries such as just as there are, arguably, innate principles of Jonathan Haidt of the University of Virginia Pakistan leads to a shockingly high number language, Hauser reviews an extensive array in Charlottesville has found, for instance, that of ‘honour killings’ every year. However, that of cross-cultural, developmental, animal and we are sometimes first viscerally shocked by does not imply that all native Pakistanis agree 909 © 2006 Nature Publishing Group AUTUMN BOOKS NATURE|Vol 443|26 October 2006 on the moral permissibility of honour killings these sorts of deep parallels because, before is done well, although the tone is sometimes as they do on the linguistic grammaticality of Hauser, nobody had really looked. Moreover, gratingly folksy, and there is some unevenness in well-formed Urdu sentences. even if morality lacks certain interesting fea- the level of knowledge assumed (nano metres These differences call into question how tures of language, the very idea of an innate and natural logarithms are used without defi- much insight the research programme devel- moral faculty is well worth investigating. Lin- nition, for example). The explanations are oped by linguists can provide into morality. guists have been exploring this idea for more clear and easy to follow, and the level of fac- For instance, some arguments for linguistic than 50 years; in the study of morality, we are tual accuracy is very high, although effective innateness are based on assumptions about the just getting started. I population size is incorrectly used instead of generative nature of language; these might not Paul Bloom and Izzat Jarudi are in the population size in the book’s only equation. export well to the moral domain. In fairness, Department of Psychology, Yale University, Carroll also turns his attention to irra- though, it might be that nobody has found New Haven, Connecticut 06520–8205, USA. tional views on a variety of topics, including the genetics of Trofim Lysenko, chiropractic ‘medicine’, and opposition to vaccination. This paves the way for a discussion of disbelief in evolution, illustrated with some remarkable Evidence for evolution quotations from US anti-evolutionists. I am stunned by the ability of people to accept the The Making of the Fittest: DNA and the showing that these can spread to high frequen- absurd and discount the rational. Carroll seems Ultimate Forensic Record of Evolution cies in times that are trivially short compared confident that the mainstream religions do not by Sean B. Carroll with the geological record. Carroll then reject evolution, but he fails to mention Islam, W. W. Norton: 2006. 301 pp. $25.95 applies these results to the way that a species for which this is far from clear. He quotes with of desert-living mouse has adapted to spatial approval a statement by Pope John Paul II on Brian Charlesworth differences in the colour of the ground, right evolution, but does not refer to Cardinal Chris- Sean Carroll begins his excellent book The down to the mutational changes that lead to toph Schönborn’s anti-darwinian diatribe in Making of the Fittest by pointing out that darker coat colour. The New York Times on 7 July 2005. Carroll’s about 50% of the American public doubt Carroll illustrates the power of natural final chapter warns of the dangers arising from the truth of darwinian evolution, yet accept selection to generate evolutionary novelties climate change and the overexploitation of nat- other aspects of biological science, such as the by discussing duplications of the opsin genes ural resources, where scientific advice is often use of DNA in forensics. His involved in vertebrates’ colour vision. Exam- ignored by governments because of economic aim is to use evidence from ples of genes and genomes that decay when considerations. modern research on DNA to their function is no longer maintained As Carroll rightly concludes: “Understanding convince the general reader by natural selection illustrate and accepting evolution is a matter of adhering of “the case for biologi- how “selection acts to the scientific process.” It is extremely impor- cal evolution as the basis tant for scien- for life’s diversity, beyond tists to fight any reasonable doubt”. the idea that He deliberately does not evolution can introduce any of the be separated standard evidence for from the rest evolution as a histori- of science sim- cal process, and only ply because of its briefly describes the unpalatable impli- use of DNA sequence cations for traditional data to re con- religious accounts of struct phylogenies. human origins. We have Instead, he uses a to insist on the fact that series of examples scientific conclusions intended to pro- are based purely on vide compelling the study of nature, evidence for the without reference basic processes to religious or other involved in evo- authority. lutionary change, Carroll’s book with particular will certainly emphasis on help the public mutation and natural selection. to understand evo- The first example involves the extraordinary only in the present, and not as an engineer or lution more clearly, but rational arguments icefish of the Antarctic, which have lost their designer”. are unfortunately unlikely to persuade those red blood cells and allowed their haemoglobin A favourite ploy of creationists is to accept whose beliefs come from prior authority, genes to decay. Carroll shows how this can be the possibility of small-scale evolutionary whether represented by a fatwa, an encyclical, interpreted as an adaptive response to life in change by darwinian means, but to deny that or the first chapter of Genesis. Wider pub- very cold water, with its high solubility of oxy- this has any relevance to the evolution of com- lic understanding of the nature of scientific gen in water and high blood viscosity. There plex structures or new species. Carroll does not evidence in general is urgently needed. I follows an exposition of Darwin’s ideas about discuss how new species evolve, but he exam- Brian Charlesworth is at the Institute of natural selection. Next comes a good but sim- ines the problem of complexity using Darwin’s Evolutionary Biology, School of Biological plified account of the standard theory of selec- example of the eye, bringing in recent results Sciences, University of Edinburgh, tion on single mutations that enhance fitness, on the molecular basis of eye formation. All this Edinburgh EH9 2BR, UK. 910 © 2006 Nature Publishing Group