As new planets are discovered every day and the search for life in and beyond our solar system becomes more and more an issue of when and where rather than if, we start to ask; what will we find first, a fossil or a living creature, a single cell or a green man with six limbs and a brain the size of an asteroid?
Since simple life precedes complex life, it seems reasonable that there is a lot more simple life than complex life in the universe. We can also assume that almost all organisms that have ever lived are now dead. It therefore seems most likely that the first proof of life we will find will be a fossil of a single cell organism, an alien prokaryote.
Perhaps that’s for the best. We don’t want to meet the creature of Neil de Grasse Tyson’s “fascinatingly disturbing thought”. At best that would be bad for humanity’s collective ego, to find that we were the stupid white men of the galaxy, at worst it would be fatal to our species, perhaps to our entire planet.
An intriguing possibility is that we will find life and not recognise it or more likely, find intelligent life and not recognise the intelligence. If our understanding of life or intelligent life is too Earth-centric, we may not recognise it when we find it on another planet, or, as Olaf Stapleton suggested , in deep space.
About forty years ago I read Stanley Weinbaum’s short story ‘A Martian Odyssey’. At the time, I though the different Martian life forms that Weinbaum described a little unlikely, because I couldn’t understand their functional morphology or behavior. Now I realize, that was the point. That is exactly how life on other worlds will look to us. Inexplicable. Another point to take from Weinbaum’s tale is that just because we have plants and animals for our complex organisms, doesn’t mean we will be limited to two, particularly these two, kingdoms on other planets. There will be life forms that will not be animals or plants. The science of Biology will take on a whole new lease of life as we start to gain some understanding of the underlying principles that apply to all life, not just life on Earth.
So, what is life? At least in our Universe, I offer this definition. Life is a self-sustaining, self-propagating complex collection of molecules capable of controlling its own destiny. Not too difficult to spot, one would think. One would look for something that could move uphill, seek out or avoid sunlight, heat acidity, pressure or conservatives. It would be capable of locating, ingesting and metabolising other living matter, and now and again, split into two while having a bit of fun doing it. Even on a planet such as this, it may be difficult to predict what form life will take, but we will probably recognise it when we see it.
The interesting thing about other planets isn’t just what kind of life they will give rise to, but what evolutionary pressures on such a planet can produce in the way of complex, or even intelligent life. Not only do I think there is a story there, but I think if you define your planet and describe its geology and history, you would be able to identify its evolutionary pressures and thus define an environment with realistic life forms with their motivations, challenges and accomplishments.
But, what is intelligent life? Here, I have no definition to offer and so I turn to the hypothetical ‘man on the Clapham omnibus’ (to hijack a legal term), and suggest that he might see, not an indivisible whole, but a collection of components such as language, memory, abstract thought including speculation, tool making and problem solving. In any individual human being, these skills are more or less developed. And in any animal, these skills are more or less developed. We see some of these components in animals as diverse as bonobos, dolphins, parrots and octopuses, but only in humans do they all come together and reach their full flowering in Beethoven’s 9th, Edwin Muir’s ‘The Horses’ or the Blue Mosque of Herat.
So if intelligence is a collection of parts, what would an animal be like who has a slightly different collection of parts, who perhaps lacks a tool making ability but can read minds. This may seem odd (and using mind reading as an example is, I admit, stretching your credulity a little) but let us briefly consider the possibilities.
First, let us detour a moment to consider some other peaks of evolutionary development, swimming, flying, communication. A whale and an octopus have radically different approaches to moving round in water. A bird and a bumble bee use different properties of air to fly and men who create vibrations in the air and ants that spread chemicals, use radically different mechanism to communicate. So is it unreasonable to suppose that human intelligence is not inevitable, but is only one solution to the evolutionary pressures faced by our ancestors? Humans have not developed the cooperative society of bees and ants, the ability to communicate over hundreds of miles like whales, the coordination of swarms of birds or fish or the inertial navigation of birds, eels or salmon. Perhaps other intelligences would incorporate some or all of these skills.
So given this possible variation, what would other types of ‘intelligence’ look like. So far it seems that S.F. authors have been rather conservative in speculating on this. In ‘Calculating God’ Rob Sawyer introduced creatures that could recognise up to 25 items without counting (humans can only manage about 4 or 5) and Larry Niven and Jerry Pournelle in ‘The Mote in God’s Eye’, describe creatures, ‘Moties’, that have such good visual judgement and such quick reactions that they had no need of traffic signals and avoided accidents on their roads merely by avoiding each other, often by only a few centimetres. Sawyer’s ‘Neanderthal Parallax’ also gives us a few ideas, though he is much more inventive when describing Neanderthal culture.
But if we look into the ever-dependable Wikipedia, we get some hints. Plant intelligence is probably the most alien to us. Artificial intelligence could give us some ideas. Another Wikipedia article adds a telling comment. “What is considered intelligent varies with culture.” A recent book on Neanderthals raises the possibility that our close cousins may have been different from us in several ways, such as not being willing to adopt new technologies, a practice of many religious sects of our day. So even on Earth, we see considerable variety. What then will the intelligent organism on another planet behave like?
Of course, the problem isn’t so much finding intelligent life (after all, if it is intelligent, it will probably be hiding from us) as recognising it when we stumble over it. First consider how we recognise life on Earth? Let us acknowledge that we have a head start in that since we currently belong to the only intelligent species on earth, we start recognizing intelligence by recognising ourselves. But what behaviours do we demonstrate that would indicate intelligence? The diurnal lemming like migration to and from work? No, I don’t think so. The fact that we board obviously manufactured dirty, smelly, polluting conveyances to do so? Probably. Trips to the store to collect our groceries? Again, probably not. The fact that we enter out airmiles number as we checkout? Definitely. Our annual migrations across country to indulge ourselves in the pleasures of snow or sunshine? Definitely not. The fact that we apply sunscreen once we get to these new locations? Possibly. The fact that we return again next year with renewed optimism, despite the broken leg or sunburn that spoilt our previous vacation? Absolutely. Keeping other animals for our own use? No, ants do that. Teaching them to fetch. Yup. Fighting? No. Waging war? Indisputably! Staring in wonder at the stars? No. Thinking there must be a god up there making the stars move across the sky? You bet.
So when we reach our alien planet, perhaps it is the artifacts and detritus of intelligent life we look for, rather than intelligence itself, the rubble, pollution, carnage and chaos that comes with intelligence. We look for the creators of that ugliness and there we find intelligence.
And if, as seems likely, we are looking for intelligence in creatures now extinct, it is appropriate that we look for what they have left. Space exploration isn’t for biologists or psychologists, it is for palaeontologists and archaeologists. These are the sciences of interstellar exploration. (See the novel Chindi for an account of archaeologists exploring the galaxy.)