Edward O. Wilson on what aliens will look like and why

It's one of the most enduring questions for humankind: why do we exist? In his new book The Meaning of Human Existence, biologist Edward O. Wilson delves into that question, by exploring science and the humanities, the ethical challenges posed by technological breakthroughs, and the meaning of religion. Wilson is a professor emeritus at Harvard University, and he's considered one of the world's most influential scientists. As part of his exploration, Wilson poses another question, one that's usually the stuff of science fiction: what would intelligent life from other worlds be like?

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Wilson says that as an evolutionary biologist he's become acutely aware of the importance of seeing humanity as just one of the vast number of possibilities. He says the way to do that is to think about how other civilized species might look, what the constraints are and what their likely features are. He uses his knowledge of evolutionary biology, archaeology and other disciplines to put together a sketch of what alien life would look like. Here are some of his ideas.

1) They would be land dwellers

"In order to have an advanced tool-making species, of course we require a concentrated source of energy, like fire, that can be transported from one place to the other and just used as a tool itself. And I can't think of a way that that can be accomplished on an aquatic planet or an aquatic part of a planet. Of course you might come up with volcanic vents as we do have on the bottom of the ocean on earth but those are very small and very scattered," said Wilson

Wilson says it took the entire African continent with its vast grasslands and great opportunities for intelligent life to emerge in large-brained to produce the human species. He believes this makes it reasonable to predict that alien life will have evolved on land.

2) Their head is distinct, big, located up front and they have light to moderate jaws and teeth

"All of the major lines of terrestrial animals, big terrestrial animals, that have evolved over and over again for over 400-million years on land have heads and sensory organs concentrated in them, up front ... E.T. is not going to have claws or horns. Claws are for carnivores and horns are typically, all through the animal world, for display and combat among members of the same species."

3) They communicate through sight and sound

"Human beings are highly unusual among all life on earth for being audio visual. We share that with birds and very few other kinds of animals. The vast majority, you could say almost all organisms on earth, plant and animal and micro-organisms, communicate by pheromone, by odour." Wilson says that if aliens had human level language it would have to be audio visual. 

"I worked out with a mathematician once how close you would have to be to an animal on earth, like an ant, in order to have that degree of modulation even possible, physically possible, and you would have to be within a millimetre of the creature you are communicating with and you just cannot evolve audio visual communication to a high degree the way we've done it unless you are audio visual in most of your sensory perception of the world."

4) They would be moral

Wilson believes this goes back to the driving force that gave rise to human society, which is, the multilevel mode of natural selection that occurs at both the individual and group levels. It follows this rule: "Within groups, selfish individuals beat altruistic individuals. Between group competition groups of altruists eat groups of selfish individuals."

"Group selection is profoundly important and it is very widespread and it is there that we have innate altruism ... We can perceive our better angels, our altruism, our kindness, our mercy, our ability to help others not as something we learn or rationally think is important, but is innate. It's biological because of the primacy of group selection that created social behaviour."

5) They won't colonize earth

"Never...because it would be a biological train wreck. You know H.G. Wells had it right. You recall that his aliens had no problem taking over earth but then they fell to the bacteria. That was really a tremendous foresight for a guy working around the turn of the last century."

Wilson thinks aliens would be in such massive incompatibility and competition with organisms on earth that in order to colonize earth they would to wipe out life on earth down to the last microbe.

"The biological systems, possibly right down to the details of the genetic code would be so different in the alien that the incompatibility that they would have microbe for microbe, insect-like creature for insect-like creature, they would probably have to bring some of their supporting fauna and flora with them."