How Can Discontinuities in Evolution Be Conceptualized?

Causal effects are different from evolutionary discontinuities. As far as Lock (2000) and Savage-Rumbaugh and Fields (2000) deal with the relation of animal behavior and human activity, they have in common that they argue against an implicit misinterpretation of evolutionary discontinuities as causal effects. As a consequence, it is argued in both papers that it is not the biologically determined animal nature that prevents primates from using human language. The two papers disagree, however, on Bickerton’s distinction of protolanguage and language proper and, therefore, on the nature of ‘ape language’. It is argued in the present commentary that this different judgment results from the fact that evolutionary progress appears continuous on the level of the individual, but discontinuous on the level of a whole population.