Paul Broca and the Evolutionary Genetics of Cerebral Asymmetry

In 1873, within two years of the publication ofThe Descent of Man, Friedrich Max Mueller wrote:There is one difficulty which Mr Darwin has not sufficiently appreciated … There is between the whole animal kingdom on the one side, and man, even in his lowest state, on the other, a barrier which no animal has ever crossed, and that barrier is – Language … If anything has a right to the name of specific difference, it is language, as we find it in man, and in man only … If we removed the name of specific difference from our philosophic dictionaries, I should still hold that nothing deserves the name of man except what is able to speak … a speaking elephant or an elephantine speaker could never be called an elephant.' and (quoting Schleicher) ‘If a pig were ever to say to me, “I am a pig” it would ipso facto cease to be a pig’.