Darwin’s theory of evolution by natural selection unifies the world of physics with the world of meaning and purpose by proposing a deeply counterintuitive ‘‘inversion of reasoning’’ (according to a 19th century critic): ‘‘to make a perfect and beautiful machine, it is not requisite to know how to make it’’ [MacKenzie RB (1868) (Nisbet & Co., London)]. Turing proposed a similar inversion: to be a perfect and beautiful computing machine, it is not requisite to know what arithmetic is. Together, these (...) ideas help to explain how we human intelligences came to be able to discern the reasons for all of the adaptations of life, including our own. (shrink)

One view of language is that it emerged in a single step in Homo sapiens, and depended on a radical transformation of human thought, involving symbolic representations and computational rules for combining them. I argue instead that language should be viewed as a communication system for the sharing of thoughts, and that thought processes themselves evolved well before the capacity to share them. One property often considered unique to language is generativity—the capacity to generate a potentially infinite variety of sentences. (...) I suggest that generativity is derived from the understanding of space and the capacity to recall or construct spatiotemporal scenarios, and probably goes far back in the evolution of animals that move in spatial habitats. Another property essential to language is theory of mind, the ability to understand what others are thinking, which probably emerged from animal empathy and became more complex in hominin evolution. Language evolved for the sharing of experiences, whether remembered or constructed, perhaps initially through pantomime but gradually conventionalized into standardized forms, including speech. These developments probably took place gradually during the Pleistocene, rather than as a sudden event in the evolution of H. sapiens. (shrink)