Inferring and Explaining

42 InferrIng and exPlaInIng alphabet. . . . Te grammars of industrial societies are no more complex than the grammars of hunter- gatherers. . . . Within societies, individual humans are profcient language users regardless of intelligence, social status, or level of education. Children are fuent speakers of complex grammatical sentences by the age of three, without beneft of formal instruction. Tey are capable of inventing languages that are more sys- tematic than those they hear, showing resemblances to languages that they have never heard, and obey grammatical principles for which there is no evidence in their environments. . . . Te ability to use a natural language belongs more to the study of human biology than human culture; it is a topic like echolocation in bats or stereopsis in monkeys, not like writing or the wheel. . . . We argue that language is no diferent from other complex abilities to such as echolocation or ste- reopsis, and the only way to explain the origin of such abilities is through the theory of natural selection. 2 Pinker and Bloom’s thesis is that our knowledge of syntax or grammar is not something we learn but is innate, something we are born with. Spi- ders don’t learn to spin webs; they simply spin them. Bats don’t learn to use echolocation; they simply use it to navigate. Babies don’t learn grammar; they already possess it as they learn their native language. Please take a moment to try your hand at schematizing Pinker and Bloom’s argument before reading further. The Argument Schematized Pinker and Bloom are defending a scientifc hypothesis about the origins of natural language and their conviction that its history lies in natu- ral selection. t 0 . The only way to explain the origin of language is through the theory of natural selection. Tey present a good deal of data in support of their theory. Here is how I would schematize their evidence: e 1 . All human societies have language. e 2 . They always have had language. e 3 . Language was not invented and did not spread. e 4 . Contemporary grammars are no more complex than those of hunter-gatherers. e 5 . Humans are profcient language users regardless of intelligence, social status, or level of education. e 6 . Children are fuent speakers of complex grammatical sentences by the age of three, without beneft of formal instruction. e 7 . Children are capable of inventing lan- guages that are more systematic than those they hear, showing resemblances to lan- guages that they have never heard and obey- ing grammatical principles for which there is no evidence in their environments. t 0 . The origin of language is explained through the theory of natural selection. Rival Explanations (of Pinker and Bloom’s Data) Asuperfcially similar theorywasfrst introduced by Noam Chomsky in the late 1950s. He argued that natural selection produced larger brains and that the ability to master a natural language so easilywas a happy by-product of this larger brain