On Writing Science Fiction: What Would Aliens Look Like?

Traveling around the universe, if it is to be any fun, requires there to be aliens. The big question for science fiction writers is: What will they look like? In my view, they would look a lot like we do, for the same reason we look like we do.

By aliens I mean creatures capable of developing societies, technology, and language, much the way we have. I don’t doubt that there microbial forms of life, or even more advanced creatures on other planets. That’s one thing. The real fun in science fiction, however, starts when there are aliens with which humans can interact on a human scale.

I’m not an expert on the origins of life on Earth, but I have a basic understanding of it, and of evolution. Even if we step way out and assume that life does not have to be carbon-based, or even that water is not necessary (ammonia, anyone?), there are practical considerations for the way we look.

We need to have depth perception. That requires at least stereoscopic vision, which in turn requires two eyes fairly close together.

To tell where sound is coming from, we need two ears arranged such the sound reaches one sufficiently before it reaches the other so the brain can detect the difference.

We need at least two arms to facilitate carrying things. I don’t suppose we couldn’t have more than two, although only two are necessary.

Hands with opposing thumbs are necessary for grasping and doing intricate manual tasks.

As to the number of legs, I don’t know of any mammals or reptiles with more than four legs. For some reason, evolution decided that two legs was the best for us. Perhaps it was because we started with four, and two of them turned into arms, and there was no need for additional legs. Two seem to have gotten the job done.

Our senses of hearing, sight, taste, and smell are close to the brain for speed of processing. We have muscles and bones for speech. We have a brain that can think and invent. It enabled us to do math, create a spoken language, and be aware of our mortality. I have no way of knowing whether other animals can do these things, even at a rudimentary level, but I’m not aware of any other species that has so much as invented the wheel, or that can build things, other than out of pure instinct, such as beavers building a dam.

In other words, (I know this may come over as a simplistic view) we have these features because they work best for survival, and for the development of complex technology and society. Therefore, I see no reason an alien, even one based on silicon, arsenic, or chlorine, would not have these features, perhaps with slight modification.

I think they would live on dry land. I don’t believe a technologically advanced civilization could develop under a sea, unless the sea were of a non-conductive material. Would we have developed electricity under water? I don’t see how we could even make metal tools.

Consider life on Earth. There have been sea creatures around longer than there have been those on land, in my understanding. Yet, no sea creatures have developed society or technology. I know that some of them are quite intelligent, but for whatever reason, and in spite of millions of years of evolution, they are still creatures swimming around the ocean without the capacity to build or create anything, and with only a rudimentary means of communicating. Things didn’t move toward humans until our ancestors crawled out of the sea.

Could an alien look substantially different? Of course. Maybe they have wings, or six arms and four legs. Maybe they can breathe carbon dioxide or methane. Maybe they communicate through telepathy. A writer could certainly sit around speculating all day coming with fantastical creatures, and I suppose there’s a class of readers who expect that. But I don’t think that’s what science fiction is about.