We think of the Earth with its mountains, valleys and rolling blue oceans as a very special place and indeed it is very special to us, it’s our home. Just like your house is special to you because it’s your home. However, when I fly over the city your house is just one of thousands of houses which are more or less indistinguishable to me.
From a scientific perspective, the same thing is true of the Earth. Our own Solar System is nothing out of the ordinary. We also know from analysis of meteorites that amino acids, the building blocks of life, are common too. So given that there are about 300 billion stars in the Milky Way most of which probably have planets, one would expect that the galaxy should be teeming with life. And yet to date, no scientifically credible evidence of alien civilisations has been found.
This is the essence of what scientists call the Fermi Paradox. Basically it asks “Where is everybody?” Dr Charley Lineweaver is a scientist at the ANU Planetary Science Institute with an unusual answer to this paradox.
“The question of extraterrestrial life is one that fascinates both scientists and the public, but often what we’re asking is not so much ‘Is there any life out there?’ As ‘Is there intelligent life out there?”
Dr Lineweaver believes that this is where the apparent paradox lies. “In our persistent pre-Darwinism we assume that humans represent some sort of pinnacle of evolution – a high point that all other species aspire to. Essentially we’re saying that we’re so great, everyone must want to be just like us.” Following this reasoning, all microbial life on all planets would ultimately evolve into creatures with human-like intelligence - ultimately leading to a universe filled with space-faring humanoids that we would encounter.
But in many ways that assumption runs counter to the way evolution works. Evolution creates life forms adapted to survive and reproduce in a given environment, but it doesn’t strive for bigger, better or smarter for their own sake.
For example, bigger lungs might enable you to breathe more effectively but if the lungs you have work perfectly well then is it worth having lungs twice the size, especially if they mean your body is bulkier and more difficult to manoeuvre? Nature’s answer to this seems to be a definite no! Each organ develops to the point where it does its job well enough but costs as little as possible in terms of the body’s resources.
That’s the essence of Dr Lineweaver’s argument. That an animal’s brain, like every other organ, has evolved to help it survive, not to score the highest on an IQ test. Evolution is about survival, not intelligence.
To test this hypothesis one could imagine a controlled experiment that begins with a planet devoid of human-like intelligence and see if less brainy animals got brainier.
If you think about it, this experiment has already been done many times by nature. “Australia is a good example.” Dr Lineweaver says “It’s been isolated from other land masses for a hundred million years. So if intelligence offers a universal advantage then one would have expected to see smarter kangaroos with a slightly bigger brains gain advantage over other kangaroos and evolve toward human-like intelligence. After all, the evolutionary increase in the size of the human brain only took three millions years and Australia has had 100 million years. The same lack of convergence on human-like intelligence can be seen in New Zealand, Madagascar, South America and other geographically isolated landmasses.”
“It’s very hard for a species that puts so much emphasis on our brains to not see that single adaptation as universally desirable.” Dr Lineweaver explains, “Equally, elephants may believe they’re great because they have the biggest noses in the jungle. But in reality, the elephant’s success is due to a combination of other features none of which is as unique as a long trunk, but collectively they’re more important to its survival.”
But even suppose for a moment intelligence were indeed a universally good idea. Perhaps there’s yet another reason we don’t see alien spaceship buzzing past all the time. There’s not necessarily a direct link between intelligence and technology.
“Dolphins have large brains and are relatively intelligent creatures yet they have little use for tools. It’s very unlikely that a dolphin will ever build a radio telescope or a rocket,” Dr Lineweaver says , “Because it doesn’t have any need for them anymore than it needs a bicycle. So you could be literally living next door to a planet full of dolphins and never detect any signs of their existence in the form of radio transmissions or spaceships.”
Like any good scientist Dr Lineweaver isn’t stating ‘this is the way it is.’ “Science is about different models that we have more or less confidence in. But I think it’s important that when we study scientific problems, we to try to isolate our thinking from our very natural but very subjective vanity.”
“If we limit our search to life forms with human-like intelligence, we are limiting our search to a single species. We might as well be looking for sulphur crested cockatoos out there. I think we should realise that our closest relatives in the universe are here on Earth, not on planet Krypton!”