Rene Descartes was probably the last great thinker to try to explain the universe on the basis of definitions and logic alone, but he was not the last savant to explain the mind that way.
I had thought I would skip reporting on Bart de Boer’s presentation in Torun. I have already covered his work on the loss of air sacs (see: Fossil Evidence of Speech?) in the human lineage. In Torun he presented experimental evidence that strengthens his case for the idea that as precision of speech sounds became more important, the air sacs used for ape vocalizations became a problem, but much of the presentation matched the one given in Barcelona. I changed my mind about reporting, however, after I began looking at the new online issue of Biolinguistics.. One of the papers directly contradicts de Boer’s conclusion, so I thought this might be a good time to take a look at the different approaches.
One of de Boer’s slides (available here) said:
Hypothesis: —Neanderthals could speak, Australopithecines not —(proto) speech is at least 500,000 years old.
It therefore seems reasonable to assume that the human I-language trait is at most 100,000 years old, its emergence having facilitated the ‘Upper Paleolithic Revolution.’ [257; italics author’s]
We seem to have a disagreement of, at a minimum, 400,000 years.