Abstract

Two extreme and contrasting positions held currently by various researchers in language evolution are compared. Each position comprises five ideas which contradict the corresponding ideas in the other position. In Extreme Position A, there was a single biological mutation, creating a new unique cognitive domain, Language, immediately enabling unlimited command of complex structures via Merge, used primarily for advanced private thought, and only derivatively for public communication, not promoted by natural selection. By contrast, in Extreme Position B, there were many cumulative biological mutations, allowing expanded interaction of pre-existing cognitive domains — no new domain was created, gradually enabling command of successively more complex structures, used primarily for public communication, and derivatively for advanced private thought, promoted by natural selection. These extreme positions are not hypothetical ‘straw men’, insofar as prominent researchers exist who adopt each of them. At the end of this paper I will present a ‘scorecard’ summarizing which parts of the two extreme positions are justified by available evidence.