- Why Only Us: Language and Evolution by Robert C. Berwick and Noam Chomsky
What, if anything, distinguishes Homo sapiens, made in the image and likeness of God, from all the other animal species in creation? Today, this is a highly disputed question that comes with a plethora of often contradictory answers from biologists, philosophers, theologians, psychologists, and many others. However, for Robert C. Berwick, a professor of computational linguistics, and Noam Chomsky, an institute professor and internationally renowned linguist, both at the Massachusetts Institute of Technology, the specific difference that defines our species is clear: human language, properly understood, is what uniquely separates us from the other animals.
In this relatively short but fascinating book, Berwick and Chomsky provide philosophers and theologians—indeed, basically any nonspecialist who is not familiar with evolutionary theory or linguistics—with an overview of contemporary biolinguistics, which is the study of language as an object in the biological world. It is a summary of what we know about the nature and the evolutionary history of human language, written by two of the world’s foremost practitioners in the field.
First, for Berwick and Chomsky, human language, rightly understood, is the product of an evolved biological capacity that gives human beings “the ability to construct a digitally infinite array of hierarchically structured expressions with determinate interpretations” (110). This ability can be reduced to a basic compositional operation that they call “Merge.” It is an operation that takes two linguistic objects as arguments—say, the words “read” and “books”—and returns a combination of the two as a new linguistic object, for example, the phrase “read books.” Merge can then recursively build on this new object, yielding more and more complex hierarchical representations, such as the sentence “he read books.”
To illustrate the hierarchical structure of language made possible by Merge, consider the sentence “Peter is too angry to eat.” It has two possible meanings. First, most obviously, it could mean that Peter is too angry to eat anything. However, it could also mean that Peter is too angry for me to eat him! The same linear sequence of words has two meanings depending on how it is hierarchically understood.
According to Berwick and Chomsky, Merge is the specific difference that distinguishes human language from the other vocal communication systems found in the animal kingdom. Animals may be able to produce linear left-to-right vocal representations, but none are able to generate a hierarchically structured communication system akin to human language. Even the celebrity chimpanzee named Nim “never progressed to the point of producing embedded, clearly hierarchically structured sentences, which every normal [End Page 618] child by age three or four can do” (145). (Incidentally, in my own view—and I cannot defend this claim here—this ability to understand and to generate hierarchical language is a sign of the immateriality of our intellects.)
The authors also make the striking claim that the architecture of human language reveals that it evolved, not as an external tool for communication between individuals but as an internal mental tool that allows an individual to conceptualize and to imagine his world. Speaking a language came only after thinking in a language. As evidence for this, they point to studies that showed that the internal hierarchical structure of language carries no information about the left-to-right order of phrases, words, or other linguistic elements. A language is spoken vocally or signed manually in an order that is imposed, not by its inherent structure but by the demands of the specific mode of externalization, whether by the production of sound or the movement of hands. This would not have been the case if language had evolved first and primarily as an external tool for human communication.
Finally, Berwick and Chomsky propose a narrative for the evolution of human language. Based on numerous paleontological and genomic studies, they think...