Actually, there is, whether or not Darwinists recognize it. Pre-Darwinian thought viewed man as a “rational animal”, and as such, there is no strict continuity between man and the anthropoid apes and higher animals in regard to “mind”. It was Darwin’s specific endeavor to change that classification by “attacking the citadel”, by which he meant the mind of man.
The purpose of the Descent of Man was to present arguments for the re-classification of man as no longer a “rational” animal but a “brute” animal. By this, Darwin clearly meant that the mind of man differs in “degree” only from the mind of anthropoid apes and higher animals. Darwin’s view is based strictly on a philosophical materialism applied to the interpretation of all of nature and the mind of man. (Confer Ever Since Darwin by S.J. Gould)
Hence, the real question is whether the current classification of man is more philosophical, i.e. based on a metaphysical materialism, than it is scientific and based on methodological naturalism. Undeniably, Darwin overstepped the boundaries of methodological naturalism, as do many of his very vocal successors.
That was the negative statement of the issue. The positive statement is that man posseses an ability not possessed in any degree by other animals. This ability, power, or capacity is that of propositional speech. No other animal possesses propositional speech, which entails conceptual thinking. Animals communication is fully explainable in terms of perceptual thinking, and the invocation of conceptual, abstract thinking (universals) for animals remains unwarranted…
Hence, the mind of man is radically different in kind from the mind of other animals. So, the current classification of man is based on the dubious assumptions of philosophical naturalism and is not implied nor required by the scientific evidence.
In sum, it is my option that proposes to give “man” a truly scientific classification.