Sciency Words A to Z: Carbon Chauvinism

Welcome to a special A to Z Challenge edition of Sciency Words!  Sciency Words is an ongoing series here on Planet Pailly about the definitions and etymologies of science or science-related terms.  In today’s post, C is for:


According to legend, Nicolas Chauvin was a French soldier during the Napoleonic Wars.  He’s described as being boastfully patriotic and doggedly loyal to Napoleon even long after Napoleon was defeated.  He was basically a joke, a caricature of a Napoleon supporter in a post-Napoleonic Europe.  And it is from Nicolas Chauvin’s name that we get the word chauvinism.

Carbon chauvinism is a term coined by Carl Sagan.  It refers to a common attitude among scientists that carbon-based life is the only kind of life that’s possible in our universe.  There are other kinds of chauvinism that the science of astrobiology has to contend with (just you wait until we get to the letter R), but carbon chauvinism is the big one, followed closely by water chauvinism.

In this 1973 interview with Rolling Stone, Sagan had this to say:

There’s carbon chauvinism, water chauvinism—you know, people who say that life elsewhere can only be based on the same chemical assumptions as we are.  Well, maybe that’s right.  But because the guys making that statement are based on carbon and water, I’m a little suspicious.

And yet despite Sagan’s little suspicions, he goes on to say in that same interview that he is a carbon chauvinist himself. And I have to admit, so am I. Carbon chauvinism is the one and only chauvinism I know of that seems to be justified.  As Sagan says:

Having gone through the alternative possibilities, I find that carbon is much better suited for making complex molecules, and much more abundant than the other things that you might think of.

Silicon is often suggested as a possible alternative to carbon, and silicon-based life forms are everywhere in science fiction. Carbon and silicon do have a great deal in common, chemically speaking.  But where carbon-based molecules are nice and wiggly—perfectly suited for all the wiggly activities of life—silicon-based molecules tend to be inflexible and kind of brittle.

So if you want to be a rock, silicon’s great! But if you want to be a life form, it’s hard to imagine why you would choose to base your biochemistry on silicon rather than carbon—carbon’s just objectively better in every way!

But then again, I am one of those people Sagan was talking about: one of those guys based on carbon.  Maybe you should be a little bit suspicious of my biases.

Next time on Sciency Words A to Z, let’s count our aliens before they’ve hatched, so to speak.  Exactly how many alien civilizations do we expect to find out there?

15 thoughts on “Sciency Words A to Z: Carbon Chauvinism

  1. This always comes down to the most difficult question in evolution. Is something the way it is because it’s the optimal solution, or by chance? Convergent evolution seems to imply that at least some solutions are optimal enough to be repeated. On the other hand, often the details of those solutions can vary dramatically.

    Carbon seems to sit at the intersection of abundance, chemical flexibility, and low energy requirements (at least in our environment). But I wonder, as the universe ages and the energy density relentlessly decreases, if elements that are reactive at far lower temperatures might not eventually win out.

    Liked by 1 person

    1. For the purposes of science fiction, I think a lot about that. I still think having silicon-based life in a story is fun. Having the silicon-based life forms come from the very distant future, when heavier elements have become more common, is one option that makes sense to me.

      Liked by 1 person

  2. Yeah, it’s always bothered me when a scientist suggests that water is necessary for life. Life as we know it, sure, but all life? Not necessarily. And yeah, carbon has so many advantages over silicon, it’s hard to imagine a silicon based lifeform arising any place where there’s plenty of carbon around to compete for the privilege.

    Liked by 1 person

    1. It sounds like that are plausible alternatives to water, like those liquid hydrocarbons on Titan. But as I’ve learned more and more about this stuff, it gets harder and harder to see how anything but carbon could do the job.


    1. I actually think putting science and history together is a great thing. So much of history has been driven by scientific advances, and when you learn about the history of how scientific discoveries were made, science becomes so much easier to understand.

      Liked by 1 person

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