The origin of life remains one of the most challenging open questions in science.
We don't know (yet) how lifeless molecules self-organized to become a living entity. We do know it happened at least here on Earth some 3.5 billion years ago, possibly earlier. Perhaps "self-organized" is the wrong word, as it gives the impression that there was some kind of intention, that life is a cosmic goal and not an accident.
If someone believes that life is the product of cosmic intent, we must ask how/what/who decided. When we use the word intent, we think of a plan, a strategy. Does the cosmos have an intelligence, a plan that features life as the main attraction? How is such a cosmos different from God? For many people, the thought of being the result of mere accident is a nonstarter. They think that to be relevant we must have been created in some fashion. After all, the word accident usually denotes something bad. Chance is a better (but not perfect) word: We are the product of chance.
If more people are to accept the message from science, we must show that being the result of chance events renders life — and particularly humans — even more special: We don't need to be created by some divine power to be relevant.
The fact that we don't know (yet) how to explain how life emerged on Earth doesn't mean we need to attribute it to some kind of supernatural action. This is the well-known "God of the gaps" approach, that what science can't explain must be the work of God. A dangerous way to believe, given that science does advance and gaps do get squeezed away.
We use science to construct descriptions of the natural world. Although it's not an infallible process, it does have something essential that distinguishes it from any other way of knowing: We can test our hypotheses, correct them and improve our descriptions. Science's power comes from its plasticity.
With that said, we can begin to wonder about intelligence. How can living matter think, strategize and, in our case at least, reflect about its existence and origin?
There are, of course, many kinds of intelligence: the collective intelligence of bees and ants (a topic our own Adam Frank explored recently), the intelligence of dolphins and chimpanzees, etc. But most of these kinds of animal intelligence are directly related to survival strategies: finding and building shelters, protection against predators, finding and trapping food. ... In our case, we do all this and much more, often creating works that are not directly related to the immediate needs of surviving. A poem or a symphony may help us appreciate life better, or the agonies of life better, but won't fill the plate with food or offer protection against a hungry lion.
What, then, is the purpose of "higher" intelligence? Is it a natural consequence of evolution — that is, if life exists somewhere, sooner or later will it evolve into intelligent creatures? Or is it an accident of natural selection, without any obvious purpose?
There are many books and scholarly articles on the relation between intelligence and evolutionary biology, which can be found here. For us, I simply point out that dinosaurs, which presumably were not intelligent — at least in any higher form — lived for 150 million years before becoming extinct. Their extinction was due to a series of events, amplified by the collision of a huge asteroid 65 million years ago. There are many ways that species may change and the pace of evolution may quicken — and huge cataclysms certainly help.
If we take the dinosaurs' story seriously, it seems that high intelligence is a sufficient but not necessary tool for dominance. Life is all about being well-adapted, in whatever way possible. Thus, the existence of life doesn't necessarily lead to the existence of highly intelligent species, capable of building rocket ships or composing operas. This means that we have something quite special, even if we don't seem to be using it in the best possible ways.
Marcelo Gleiser's latest book is The Island of Knowledge: The Limits of Science and the Search for Meaning. You can keep up with Marcelo on Facebook and Twitter: @mgleiser