I support the application of the “evolution as tinkering” idea to vocalization and emphasize that some of the subcortical parts of the brain circuits used for speech organs retain features common to nonprimate mammals, and in some cases to lower vertebrates, pointing up the importance of cortical evolution as suggested by MacNeilage.

Wilkins & Wakefield are clearly right to separate linguistic capacity from communicative ability, if only because other animal species have one without the other. But I question the abruptness of the demarcation they make between a period when hominids evolved enriched conceptual representation for other reasons entirely, and a subsequent later stage when language use became an adaptation.

One can disagree with Müller that it is neurobiologically questionable to suppose that human language is innate, specialized, and species-specific, yet agree that the precise brain mechanisms controlling language in any individual will be influenced by epigenesis and genetic variability, and that the interplay between inherited and acquired aspects of linguistic capacity deserves to be investigated.

I do not disagree with the argument that human-population right-handedness may in some way be a consequence of the population-level left-lateralization of language. But I suggest that the human functional lateralization is not dependent on the structural left-right brain asymmetries to which Corballis refers.

Heyes is right that behavioural tests able to distinguish mentalistic from nonmentalistic alternatives should be sought, but the theoretical issue is less about the passing of behavioural tests than it is about the internal mechanisms which allow the passing of the tests. It may be helpful to try to assess the internal mechanisms directly by measuring brain activities.