International Society for Science & Religion - Library Project

The Symbolic Species: The Co-Evolution of Language and the Brain

by Terrence W. Deacon

Introductory Essay by V. V. Raman

This book is not a repetition of well-established facts on evolution, but fresh perspectives on a related puzzle: Why are humans the only species with the capacity for learning and using extraordinarily complex language?

Deacon analyzes the nature of language and talks about our unique ability to think in “abstractions, impossibilities, and paradoxes” [22]. He challenges us to recognize that human language is an altogether different category of communication from whatever modes have evolved in other species. It all started when “our ancestors found a way to create and reproduce a simple system of symbols, and once available, these symbolic tools quickly became indispensable” [45]. The book discusses the relationship between words and meanings, and explains why “symbols aren’t simple” [69]. Its analysis “forces us entirely to rethink current ideas about the nature of grammatical knowledge and how it comes to be acquired” [101]. In the second and third chapters Deacon debunks the common brain-computer analogy which, he explains, misses the point that symbolic reference is reference-mediated by a system of relationships, not just by simple correspondence.

Deacon challenges the Universal Grammar thesis that “the source of prior support for language acquisition must originate from inside the brain,” and proposes that it is “outside brains, in language itself” [105]. He describes “the presumed relationship between brain size and intelligence” [147] as a gross misunderstanding, and suggests that developmental neurobiology “can help explain why it matters how the human difference in brain size was achieved” [192]. He extends and modifies “the classic notions of proper mass as applied to brain structure, by extrapolating the analysis to circuitry relationships” [223].

Symbols are “relationships between tokens,” and “widely distributed neural systems must contribute in a coordinated fashion to create and interpret symbolic relationships” [266]. Indeed, “individual linguistic symbols are not exactly located anywhere,… the brain structures necessary for their analysis seem to be distributed across many areas” [300]. Deacon’s account of  how language played a role in brain evolution depends on understanding that the special demands of discovering and internalizing this system of relationships imposed unusual selection pressures on brain functions not previously under significant demand.

In the chapter “And the Word became Flesh”, Deacon elaborates on the idea that the changes brought about in the evolutionary miracle of the human brain “were a direct consequence of the use of words” [322]. Calling our species Homo symbolicus, he reminds us that the first cave paintings and carvings “give us the first direct expression of the symbolizing mind” [374].