By Mano Singham

One of the things that makes some people uneasy about the theory of evolution is its implication that humans are just one branch in the tree of life, connected to every other living thing through common ancestors, and thus not special in any mysterious way. It is surely tempting to think that we must be somehow unique. Look at the art and culture and science and technology we have produced and for which nothing comparable exists by any other species. How can we explain that if we are not possessed of some quality not present in other species?

One doesn't have to look far to find one feature that distinguishes the human species from all its cousins in the evolutionary tree of life. It is language. Somehow, at some point, we developed the capacity to speak and communicate with each other through well-articulated sounds and that has had a profound impact on our subsequent development. Although the number of phonemes (units of sound) that humans can make (about fifty) is not vastly greater than the number available to apes (about a dozen), we can use them to generate an average vocabulary of about 100,000 words. "As a consequence, the capacity of Homo sapiens for rapid, detailed communication and richness of thought is unmatched in the world of nature." (Richard Leakey, The Origin of Humankind, 1994, p. 122)

Without language, the knowledge of animals is restricted to what they are born with as a result of their evolutionary development (i.e., their instincts) and what they acquire during their own lifetimes. That is necessarily restricted and each generation essentially starts life at the same point in knowledge space as the previous one.

But with language, all that changes. Now knowledge can be passed on from generation to generation and we can learn from our ancestors. Knowledge becomes cumulative and the process accelerated with the discovery of writing about 6,000 years ago, resulting in the ability to store and retrieve knowledge over long times and long distances.

I have sometimes wondered why religious people, always on the lookout for a sign that humans are special in god's eyes and possessed of some quality that could not be accounted for evolutionarily, have not seized on language as that which makes us uniquely human. Why don't intelligent design advocates suggest that it was god's intervention that enabled us to develop the ability to speak?

One advantage to religious people of using the introduction of language as a mysterious sign of god's actions is that it is hard to pin down exactly when and how language started, and thus might make it hard to explain scientifically, making it an even better choice for a religious explanation than the bacterial flagellum or even the origin of life. Language was a significant development in our evolutionary history but how it came about is murky because spoken language leaves no trace.

Of course, the fact that we humans possess a unique feature does not necessarily imply that we are special. After all, elephants can also boast of a uniquely useful organ, the trunk, that can do truly amazing things. It is strong enough to uproot trees and stack them carefully in place. It is delicate enough that it can pick a thorn, draw characters on paper with a pencil, or pick up a pin. It is dexterous enough that it can uncork a bottle and unbolt a latch. It is sensitive enough to smell a python or food up to a mile away. It can be used as a siphon and a snorkel. And it can do many more things, both strong and delicate. (Steven Pinker, The Language Instinct, 1994, p. 340)

Why did only elephants evolve this extremely useful organ compared to which the human nose seems so inadequate? It presumably developed according to the laws of natural selection, just like everything else. But if elephants were religious, they might well be tempted to argue that having a trunk was a sign from god that they were special and made in god's image, and thus that god must have a trunk too.

So uniqueness alone doesn't imply that we are possessed of some spiritual essence. But even if the ability to speak does not confer on us a mystical power, the question of when and how humans developed this profound and incredibly useful ability is well worth studying.

Next: When did language originate?