In this post and in following posts, I want to discuss these two questions: is human language irreducibly complex, and if so, what would be the implications of that irreducible complexity? However, before addressing these questions, it is important to understand what the term "irreducibly complex" means.
The concept of irreducible complexity first gained prominence in biochemist Michael Behe's 1996 book Darwin's Black Box. According to Behe (as I understand him), a system is irreducibly complex if the removal of one component of that system would make it unable to function. Behe applied this concept to certain features of biological organisms, the most famous example of which may be the bacterial flagellum. The bacterial flegellum is a sort of rotary propellor that enables certain bacteria to "swim." It is constructed of numerous elements, all of which are needed for it to function. In Behe's view, the irreducible complexity of the bacterial flagellum and other biological systems poses a major challenge to the theory of neo-Darwinian evolution. This is because neo-Darwinian evolution requires that the various elements of a biological system (like the human eye) develop piece-by-piece (and by chance) over a long period of time. However, if it were the case that these systems developed piece-by-piece over a long period, these systems would have been wholly nonfunctional (and thus of no benefit to the organism in which they appeared) suntil all the pieces were in place. Consequently, it would appear that such systems were not the product of some gradual, random process of evolution, but rather came into existance as fully functional systems from the start. This in turn would suggest that such systems were in fact designed since it seems unlikely that all the necessary elements would have come together spontaneously by chance.
Behe applied the concept of irreducible complexity to biological systems, but some time ago it occurred to me that this concept could be applied to human language as well. I am certainly not the first to think this, as I discovered while reading an article which appeared in the June 2007 issue of Colorado Research in Linguistics, entitled "The Evolution of Evolutionary Linguistics" (which I found in pdf form on the internet at colorado.edu). In this article, the author, Jeffrey Roesler Stebbins, begins a discussion of the building blocks of human language thus:
Some precursors of speech are obvious, even to lay persons: the abilities to speak and to hear, agreed upon lists of words, and so on. But within linguistics, psycholinguists, phonologists, syntacticians, semanticists and others each emphasize their own respective foci of study, whether they are conceptual frameworks, vocal physiology, systems of reference, or word order. Nobody seems able to agree upon the sequence in which these several elements of speech must have evolved, or even if it would have been possible for any of the phenomena to emerge without the simultaneous emergence of all of them. Such is the interrelatedness of the ingredients of language that linguists have difficulty imagining any existing independent of most others. The index to Jackendoff’s Foundations of Language, for example, lists 18 interface relationships (in which one element of language interfaces with another): intonation with syntax, phonology with conceptual structures, syntax with semantics and pragmatics, and gestures with morphophonology are just four examples...Some have even wondered whether language might actually be an irreducibly complex system, which would necessarily preclude it evolving piecemeal, a bit at a time. (emphasis mine)
From this passage, we can see one of the ways in which, it can be argued, human language is irreducibly complex: the various elements that make up language are so interrelated that it seems that language would not function as language without all of them. Let us take just one of the relationships Stebbins mentions to elucidate this idea--the relationship between syntax (the structure of language) and semantics (the meaning of language). In English, the sentences Bob kissed Mary and Mary kissed Bob have different meanings. This is because in English nouns or pronouns appearing before a verb in a simple statement are interpreted as the subject and those appearing after the verb are interpreted as the object. Hence, the way the words in a sentence are arranged (the structure of the sentence) determine their (and the sentence's) meaning. If there were not such a relationship between structure and meaning, we would have no way of knowing for certain what a speaker's meaning was in a particular utterance. And remember, this is but one of a number of relationships that exist among the various elements making up human language.
It is also noteworthy that, as Stebbins points out, no one can even agree on the order in which the various elements of language evolved. To create a convincing evolutionary explanation of the origin of language, it is essential to be able to posit a plausible sequence in which the components of language emerged. Otherwise, it must be assumed that language emerged suddenly, all at once--rather like those life forms that appeared all of a sudden, without any apparent ancestors, during the so-called Cambrian explosion. However, a sudden emergence of human language does not really comport well with the gradualism assumed in neo-Darwinism.
In short, the "interrelatedness of the ingredients of language" strongly suggest that human language is irreducibly complex. In following posts, I hope to provide further evidence for the claim that language is irreducibly complex and discuss the implications of such a claim.
Image of Prof. Michael Behe from uncommondescent.com