Why Only Us: Language and Evolution
by robert c. berwick and noam chomsky
mit press, 224 pages, $22.95
Perhaps the most sensitive point of contact between religion and science is the issue of human distinctiveness. Christian teaching affirms that there is an “ontological discontinuity” between humans and other animals. Only humans are made in the image of God and have immortal souls endowed with the spiritual powers of rationality and freedom. This does not admit of degrees: One either has an immortal soul or one does not. The discontinuity must therefore be historical as well as ontological. In our lineage there must have been a first creature or set of creatures who were human in the theological sense, but whose immediate progenitors were not.
This seems to fly in the face of evolutionary biology. Evolution occurs gradually, by the accumulation of genetic changes that spread through populations. New species do not appear at a single stroke, in one generation; there was not a “first cat” whose parents were non-cats. There is no contradiction with theology, however. Biological speciation is indeed a gradual process, but in the traditional Christian view, the conferring of a spiritual soul upon human beings is not a biological process at all. It is quite consistent to suppose that a long, slow evolutionary development led to the emergence of an interbreeding population of “anatomically modern humans,” as paleo-archeologists call them, and that when the time was ripe, God chose to raise one, several, or all members of that population to the spiritual level of rationality and freedom.
Many authors, including C. S. Lewis, have proposed such a view of human origins. It is suggested also in the Vatican document “Communion and Stewardship: Human Persons Created in the Image of God,” issued in 2004 with the authorization of then Cardinal Ratzinger:
Catholic theology affirms that the emergence of the first members of the human species (whether as individuals or in populations) represents an event that is not susceptible of a purely natural explanation and which can appropriately be attributed to divine intervention. Acting indirectly through causal chains operating from the beginning of cosmic history, God prepared the way for what Pope John Paul II has called “an ontological leap . . . the moment of transition to the spiritual.”
The idea of human exceptionalism goes against the grain of much of modern thought. Since the time of Copernicus, science has eschewed anthropocentrism in any form. And several major breakthroughs in science have been seen as contributing to what Stephen Jay Gould called “the dethronement of man.” Not surprisingly, therefore, a great deal of recent research has been devoted to finding animal analogues of human mental abilities.
It has been found, for instance, that some species are remarkably clever problem-solvers, including animals as simple and distant from us evolutionarily as crows. The “mirror self-recognition test” suggests that some kinds of animals have some self-awareness. Several species use tools, such as rocks to crack nuts, and some even “make” tools; for example, elephants tear branches from trees to use as flyswatters and monkeys strip leaves off of sticks and use them to draw insects out of holes. In 1999, an article in Nature went so far as to claim that chimpanzees have “cultures,” because different bands of them exhibit numerous differences in “technology and social customs.”
None of this adds up to rationality, of course, which most people would agree emerged only in the genus Homo. When it emerged and how, whether slowly or suddenly, cannot be studied directly, unless one has a time machine. Therefore arguments in this area are highly inferential. One approach is to look for signs of creative activities that require symbolic thought, such as art, body decoration, finely wrought tools of novel materials, “grave goods” (possibly indicating belief in an afterlife), and so on—what one author calls “the five behavioral B’s: blades, beads, burials, bone tool-making, and beauty.” These seem to appear only with Homo sapiens and proliferate rather suddenly (in evolutionary terms) roughly 50,000 years ago. The earliest symbolic artifact found so far is a piece of ochre with a cross-hatch design carved in it, discovered in the Blombos Cave in South Africa and dated to about 80,000 years ago.
A more promising approach to finding the beginnings of human rationality may lie with the study of language. This is paradoxical, perhaps, in that spoken language leaves no fossils or artifacts. One can, however, investigate the neural machinery of language, the genetic basis of that machinery, and the deep underlying structures of language itself. This is the avenue pursued in the remarkable new book Why Only Us by Robert C. Berwick and Noam Chomsky. It is a breathtaking intellectual synthesis. Using an array of sophisticated arguments based on discoveries in linguistics, neuroscience, genetics, computer science, evolutionary theory, and studies of animal communication, they develop a set of hypotheses about the nature and origins of human language, which will (if they hold up) have far-reaching implications. As the title of their book implies, Berwick and Chomsky argue that only human beings have language. It is not that there are other animals possessing it in germ or to a slight degree; no other animals, they insist, possess it at all. The language capacity arose very suddenly, they say, likely in a single member of the species Homo sapiens, as a consequence of a very few fortuitous and unlikely genetic mutations.
