To the editors:

“It is customary to refer to Noam Chomsky’s Aspects of the Theory of Syntax as the founding document of Generative Grammar—and justifiably so.”¹ This is how Ángel Gallego and Dennis Ott start their introductory remarks to a fifty-year retrospection on this milestone in generative thinking and theorizing. In her essay, Anna Maria Di Sciullo sings the same tune, and her melody is equally harmonious.

As she puts it: “A revolution was in prospect. Having heard thunder, linguists were eager to see lightening [sic]. They were not disappointed. Aspects consolidated the revolution.” Di Sciullo then paints the revolutionary picture of the genesis of generative grammar: “In undertaking a revolution, Chomsky did what revolutionaries often do. He created his own predecessors, Plato and René Descartes among them.” She later adds, among others, Wilhelm von Humboldt—he of “infinite use of finite means”—to the narrative. Even if unmentioned, Humboldt’s insight was already featured in Syntactic Structures, where Chomsky wrote that “a grammar mirrors the behavior of the speaker who, on the basis of a finite and accidental experience with language, can produce or understand an indefinite number of new sentences.”² The relevance of this triple will become apparent shortly.

In the Aspects retrospection volume, David Pesetsky, whom Di Sciullo also cites—though it should read “Writing almost fifty years later”—remarks “how breathtakingly modern this book remains, and how old-fashioned it has become.”³ Di Sciullo’s review essay illustrates both points very well. Take, to mention just one, the property of human language known as recursion, which has received much attention since the language faculty was distinguished into the faculty of language in the broad sense and the faculty of language in the narrow sense.⁴ Recursion took a central role in Aspects, as can be summed up with Di Sciullo, although she placed this sentence in a different context: “The result is what Aspects, in a phrase now famous, called deep structure.” Having first introduced deep structure as a technical term in Aspects, Chomsky related it to what are at first glance similar notions from Humboldt, Ludwig Wittgenstein, and even Charles Hockett.⁵ These comparisons may sound outlandishly old-fashioned today. Yet, the modern discussion of recursion does have its roots in Aspects, where it was encoded at that level of deep structure.⁶

It should not be forgotten that Aspects was one of several linguistic books of Chomsky’s that appeared in quick succession. It fell in the middle, the year after a brief technical work was published, Current Issues in Linguistic Theory, and the year before another, Topics in the Theory of Generative Grammar, as well as a more foundational essay, Cartesian Linguistics.⁷ Not surprisingly, topics from each found their way into Aspects, which expands especially on the theoretical framework from Current Issues, itself an extended version of an earlier essay. Likewise, Cartesian Linguistics picked up several of the philosophical underpinnings of the generative enterprise from Aspects that Di Sciullo aptly reviewed.

Also around this time saw the publication of Eric Lenneberg’s seminal work, which more or less directly led to the research program that over the past two decades has become more widely known as biolinguistics. Lenneberg’s Biological Foundations of Language also contained a technical appendix by Chomsky.⁸ The fifth relevant book in those same years was, of course, The Sound Pattern of English, written with the late Morris Halle, which lays out an explicit generative framework of phonology.⁹

Over the ensuing six decades and counting, these cited works alone led to the fruitful development of the generative approach to the syntax, semantics, phonology, and philosophy of natural language. Apart from this enormous body of work and wealth of ideas, both technical-theoretical and philosophical-foundational, the research agenda opened up an even wider realm of scientific inquiry. Biolinguistics is built on the premise that modern linguistic theory is still engaged in providing satisfactory answers to what may be called the five foundational questions.¹⁰ These can be abbreviated as follows, with each formulation dubbed a specific problem in reference to their intellectual origin or connection.¹¹

1. What is knowledge of language? (Humboldt’s problem)
2. How is that knowledge acquired? (Plato’s problem)
3. How is that knowledge put to use? (Descartes’s problem)
4. How is that knowledge implemented in the brain? (Broca’s problem)
5. How did that knowledge emerge in the species? (Darwin’s/Wallace’s problem)

The first three—the better known and original—problems were coined by Noam Chomsky: Humboldt’s problem,¹² Plato’s problem,¹³ and Descartes’s problem.¹⁴ This triplet can be traced back to Aspects. The other two were identified later, in part due to technical advances. Broca’s problem was named as such by Cedric Boeckx, who is also often cited as the name-giver of Darwin’s problem, though in the context of biolinguistics, Koji Fujita had already introduced it.¹⁵ An alternative denotation would be Wallace’s problem.¹⁶ In other words, at the beginning of the biolinguistics enterprise, we once again find Aspects, and we can also return to it to look at the future of at least one type of linguistic inquiry.

This type, biolinguistics at large, “aims to derive linguistic facts from first principles, an ultimate goal linguistics shares with science,” as Di Sciullo writes. While she laments Chomsky’s apparent defiance in his claim that “Linguistic theory is mentalistic,” she notes, “Linguistic theory is still mentalistic, but step-by-step, research is uncovering its physical roots in the neurophysiology of the human brain.”¹⁷ This biolinguistic outlook essentially stems from Aspects and is very much a child of its times, especially through the influence of Lenneberg on Chomsky’s thinking.

Kleanthes Grohmann

Anna Maria Di Sciullo replies:

It is difficult not to underline the importance of Aspects, and, more broadly, of the scientific revolution brought about by the generative enterprise. I am pleased to read Kleanthes Grohmann’s letter, which conveys the same appreciation. In my reply, I will expand on why biolinguistics is important and mention some recent results bridging the geometry of syntactic trees, language acquisition, and language processing.

Grohmann is right in focusing his letter on biolinguistics, the study of the biology of language, and in referring to Eric Lenneberg’s seminal work Biological Foundations of Language, thereby adding to the reference list already provided in my essay.¹⁸ Biolinguistics is an important dimension of the generative enterprise. Defining the object of inquiry of linguistic theory as being the language internal to the mind—namely the generative system underlying language creativity and enabling language acquisition—led to the creation of a new interdisciplinary field of inquiry devoted to the study of the biological basis of language, bridging linguistics, biology, and other sciences.

Biolinguistics research aims to understand language as an organic system. Results in first language acquisition and neurosciences confirm the importance of generative grammar theory for understanding language and its acquisition by the child as natural phenomena. Language requires a genetic base, develops with exposure to the environment, and is subject to natural laws.¹⁹ Under normal conditions, it develops very early in the child without conscious efforts or extensive training. The fact that children typically do not make errors violating the principle of structure-dependency also indicates that the latter is a first principle of the language faculty.²⁰

Current studies indicate that complex functional sequences, such as the one postulated in syntactic cartography, develop gradually in the child. Based on a corpus of natural productions, research in this area indicates that the lower parts of the tree are acquired first.²¹ This result suggests that the language acquisition path is sensitive to the geometry of syntactic trees, as well as to the gradual installment of principles of efficient computation. 

Results in brain studies have narrowed the gap between language and biology. Brain imaging studies, for example, have identified different Brodmann areas associated with structural hierarchy and displacements of syntactic constituents.²² Other neuroimaging results differentiate sequences from hierarchically structured constituents.²³ In these studies, merge activation peaks show very little variance across individuals, suggesting an invariant neurobiological basis for this syntactic operation.²⁴ By contrast, other studies indicate that the human brain is sensitive to structure-dependent computation when processing language, and not flat structure.²⁵ These results add support for the model of the language internal to the mind, or I-language, stemming from the generative enterprise in which Aspects is an important cornerstone.