Sir

The review by the linguist David Poeppel of The Symbolic Species: The Co-Evolution of Language and the Brain by the neuroscientist Terrence Deacon (Nature 388, 734; 1997) sounds similar to a priest defending an established and powerful religion.

Where science and religion should differ is the way in which new ideas are treated. Deacon makes a good case for a theory of evolution of language in his book, which is dismissed in Poeppel's review as merely a willingness to contribute an unimaginative opinion.

Deacon was even attacked for comparing primates with humans in his book. Unless one denies that humans evolved from primates, looking for evolutionary cues of language in non-human primates can only add to our knowledge.

After all, our language capacity does not come overnight and we are not the only species that talks and listens.

Until we fully understand the mechanisms underlying human speech and language, we should not ridicule others for suggesting alternative explanations to the long-standing problem of language evolution. The debate should not be trivialized to an argument between ‘good guys’ and ‘bad guys’. In science, we should believe only in the truth, not in one view or the other.