Support Provided ByLearn More
Space + FlightSpace & Flight

Beliefs About Alien Intelligence

Do intelligent aliens exist in the universe? In this interview, Michael Shermer, author and founder of the Skeptics Society, helps deconstruct the question of extraterrestrial intelligence, along the way touching on topics as wide-ranging as intelligence swarms, carbon chauvinism, Neanderthals, and protoscience, to name just a few.


Receive emails about upcoming NOVA programs and related content, as well as featured reporting about current events through a science lens.

Michael Shermer
Michael Shermer is the founder of the Skeptics Society, editor in chief of
Support Provided ByLearn More
Skeptic magazine, and the author of several books about beliefs, including most recently, The Believing Brain.
Byrd Williams, ©Michael Shermer


NOVA: Do you remember when you first became interested in the question of extraterrestrial intelligence?

Michael Shermer: I'm a big Star Trek fan, so that's part of the whole sci-fi scenario. But then I got interested, as so many people have, through Carl Sagan's writings and TV shows and all that stuff. He more than anybody else really is the one who popularized it as a legitimate question to ask and think about. So that influenced me.

But I'm also really interested in evolutionary theory. One of the great questions was, as Steve Gould always put it, if you rewound the tape and played it again, would we end up with somebody like us? Not Homo sapiens, but an intelligent creature that can make spacecraft or radio telescopes or whatever so that they can communicate?

ET [extraterrestrial intelligence] is the same question. It's rewinding the tape on another planet and seeing if we end up with something with intelligence. I think that's just one of the great thought experiments that we can run that helps us think about evolution. There are certain convergences. You can end up with things like ears and eyes and skin and just basic senses and things to get around your home planet—legs and arms and whatever you call them. And you likely have all the sensory apparatus in the brain on one end and waste-disposal systems on the other end. So you kind of end up with something like us.

The counterargument to that is: Then how come there aren't that many creatures like us on Earth? Of the hundreds of millions of species that have evolved, only a tiny handful of them end up as bipedal primates. To me that's why it's interesting.


How would you define intelligence?

The ability to process information in a way that's progressively cumulative so you can use it for survival, and not just for survival but for advancing your species, problem-solving, that sort of thing.

"If big brains are such a great idea, how come hardly anyone has them?"

Do you think it's possible that intelligent creatures have evolved on other planets? And if so, will we ever hear from them?

I always separate the questions. Are they out there, and have they come here (just to dispose of the UFO people)? They haven't come here, but we're not close-minded to the idea that they might be out there. The only way to find out at the moment, since we don't have a deep space exploration program for that sort of thing, is radio signature or some other signature like that. Any creatures that can do that would have to be intelligent by any definition—some kind of tool-using, problem-solving, information-processing, manipulating-your-environment creatures—or else we wouldn't detect them. It's almost definitional. If they're not that, then we're not going to find them. They may have some completely different kind of intelligence. Maybe they're all marine mammals living in the water, so we're never going to find them. You end up restricting your definition so you can look at them somehow.

So it's an operational definition?

Yeah, operational.

Do you think intelligence is the natural end product of evolution?

It's one solution to solving life's problems. Obviously it's not that important, because most species on Earth are pretty simple. They solve life's problems elegantly without any higher forms of intelligence at all as we've defined it. If big brains are such a great idea, how come hardly anyone has them? Everybody always says this was a great invention that evolution bestowed on us for adaptive reasons. Well, it can't be that adaptive or else other creatures would have it. The trade-off is that it's really expensive to run a brain this big. There are a lot of trade-offs and downsides to it, so that's probably why it doesn't happen very often.

The whole thing is so improbable that if you rewound the tape and played it all the way back to 35,000 years ago here on Earth, we [fully modern Homo sapiens] wouldn't be here. It'd just be Neanderthals. They were probably not on the road to building spacecraft and telescopes and radio signals and computers and things like that. It's pretty improbable, but then the numbers are so big—100 billion stars, probably lots of them have planets—so just by the law of large numbers, you're bound to get something like us. It's almost inevitable.


Are we hampered in our efforts to answer this question because we only have ourselves?

Yeah, we're kind of restricted, and we're pretty chauvinistic about the way things ought to be. Sagan used to call it carbon chauvinism, but I think we're worse than that. We're air-breathing chauvinists and big-brain chauvinists and bipedalism chauvinists. I think there are lots of ways to be chauvinistic.

And there are a lot more ways to be intelligent that we probably can't think of. I like the science fiction writers who speculate about clouds of hydrogen gas that can become intelligent. There may be just so many ways we can't even think of how that could happen. We've really only thought about this seriously for maybe a century in terms of artificial intelligence and trying to deconstruct how our brains work so we can reconstruct it in computers. All of that helps us think about how it might have happened somewhere else. But again, it's just us. We're just looking at our brain, which we really don't even understand that well.

People have suggested that it's arrogant to think that we're alone in the universe, and others have said that it's arrogant to think that intelligence like ours is pre-ordained. Do you see areas of science in which such thinking is more prevelant?

Yeah, it's where the data are fuzzy, or there are not enough data to make conclusions. Like the climate change stuff. The fact that there could be consensus bothers a lot of people. Like, wait, science is based on consensus? Because the model is really complex and the math is difficult, so it really does take experts, and presumably they check each other and reach a consensus based on massive amounts of data and different lines of inquiry, and you have a convergence of evidence. And that's not going to happen in a nascent field, a field that's just kind of struggling to get started. I think climate change was there maybe 15 years ago. In the last 10 years or so, I think there's been a massive amount of data coming in that makes it pretty clear that we can say there's a consensus.

"SETI is real science, or at least it's protoscience. They're working toward that."

We're never going to have that with SETI and the whole ET question until we find something. And even that's just a start, so it's all speculative now. But even if we never find anything, just asking the question and thinking about it is a useful enterprise to understand ourselves, evolution, history. Just thinking about how life might start on another planet and evolve into intelligence forces us to think about how that happened here. And that is legitimate science.

So is SETI science?

I call it a protoscience. It's a little bit like string theory, which is not pseudoscience and yet it's a little bit more than just pure mathematics. There's a little metaphysics in there. But still there are no data. The string theorists admit we don't have any experimental evidence at all. But I wouldn't say that's pseudoscience, because it's still a useful enterprise that real scientists can work in and generate new hypotheses with that could in principle be tested. So it's the "in principle can it be tested," and "is it usable to other scientists?" that are the criteria for science.

UFO-ology is a pseudoscience, because they're not attempting to test hypotheses and falsify their claims. They have a different kind of agenda, and I think it's something different than what the SETI scientists do. SETI is real science, or at least it's protoscience. They're working toward that.

Can you imagine useful technology coming out of the search for extraterrestrial intelligence?

Well, certainly the algorithms that they've developed for detecting a signal within the noise are very useful, because that's what all science does—we seek and find patterns. The question is, are the patterns real or not? There has to be some way, some algorithm that you can apply to say here's the rule; if it does this, then we can conclude it's intelligence. It's like in archeology where they try to determine if stone tools were intentionally chipped or accidentally chipped. Or if the nick on the bone is from somebody stomping on it, or if somebody actually bit into it, or if a rock fell on it. They actually have techniques to determine whether it's this or that. That's the kind of useful thing I think that SETI provides: thinking about how you would tell the difference between signal and noise. Because all science is a signal-to-noise problem.

What do you think are the strongest arguments for extraterrestrial intelligence. Is it the sheer numbers of planets?

In general, the numbers, yes, and then more encouragingly in the last 10 years is the discovery of all these extra-solar system planets. At first it was that maybe 10 percent of stars have planets, but that was pure guesswork. And then they found one and they found another one, and they say maybe we have evidence that it is 10 percent, maybe it's 20 percent. And now it's like 50 percent, 90 percent, maybe every one of them has planets. So let's say that it's a dozen or even 10 or something and you've got 100 billion [stars]. So a thousand times 10, a thousand billion, that's a trillion. That's a trillion planets in our galaxy alone. That's a hell of a lot of real estate for all those little bacteria to eventually become big brains on at least one of them, if not more. So I think that's our biggest hope.

How come they're not here? This so-called Fermi Paradox problem is still real. And it's getting more real, because they probably are out there. So where are they? They're not likely to be close to us in an evolutionary time scale. They are going to be way ahead of us. At least half of them will be ahead of us, assuming we're in the middle of the bell curve in our evolution. Assuming they discover Moore's law or whatever they would call it—the law of accelerating returns of cumulative science technology—they should figure out space travel. They should be here! Of course, the UFO people say they are here, but they're not, so where are they?

My answer to that is that it's just a huge place, it's mostly empty space, it's hard to get from here to there, and there aren't that many of them out there. SETI optimistically said a million intelligent life-forms in our galaxy alone. I think that's way optimistic. I think we're talking probably hundreds maybe, or dozens, and given the vast distances in interstellar space, the chances of finding us are pretty slim. That's the answer [to the Fermi Paradox], I think.

Maybe we're also being chauvinists in this regard. Maybe other intelligences don't like to explore.

That's right. Maybe they've developed virtual reality that's way better than the real thing. Maybe they sit around with their little virtual travel trips or whatever, and they do all that just in their living room.

Right. Who cares what's out there!

But not all of them. Surely some of them will want to go see the real thing.

You've written a book about beliefs, and how beliefs come first and the search for evidence for those beliefs comes second. Do you think that it's a belief that alien intelligences are out there?

I guess to a certain extent it's a belief. It's a little bit different than other beliefs, though. It's a belief based on confidence in the numbers. It's a provisional belief, given that it could change in a heartbeat in one way, if it's confirmed. But it can never be disconfirmed. We're never going to be able to look at every nook and cranny of the universe. The only thing we can do is confirm that ET is out there. So that expands the belief to, like, what do you think? Maybe belief isn't even the right word. What's your intuition? What's your instinct about the numbers? What's your guess? It's more like that. So it's different than, say, belief in civil liberties or democracy, or belief in evolution, or even in gravity, because that's been confirmed. It's in between those.

Is there anything else you'd like to cover?

The funding of SETI. I think there is probably private funding out there. Should the government do it? Well, I don't know. We have so many other problems. I have to admit that as a general observer of culture I don't know if it's the best use of government money. I think private money would be the better solution for that. It's such a long shot, and compared to, say, infrastructure and fixing bridges, should we be looking for aliens?