It is a very remarkable fact that there are none so depraved and stupid, without even excepting idiots, that they cannot arrange different words together, forming of them a statement by which they make known their thoughts; while, on the other hand, there is no other animal, however perfect and fortunately circumstanced it may be, which can do the same.
Descartes goes on to state that one of the major differences between humans and animals is that human use of language is not just a response to external, or even internal, stimuli, as are the sounds and gestures of animals. He warns against confusing human use of language with “natural movements which betray passions and may be . . . manifested by animals.”
To hold that animals communicate by systems qualitatively different from human language systems is not to claim human superiority. Humans are not inferior to the one-celled amoeba because they cannot reproduce by splitting in two; they are just different sexually. They are not inferior to hunting dogs, whose sense of smell is far better than that of human animals. As we will discuss in the next chapter, the human language ability is rooted in the human brain, just as the communication systems of other species are determined by their bio- logical structure. All the studies of animal communication systems, including those of primates, provide evidence for Descartes’ distinction between other ani- mal communication systems and the linguistic creative ability possessed by the human animal.