I’ve talked about this before, you all know my opinions on it. But I’m bringing it up again because I think its important, not just because it tells us something about the universe we live in, but about ourselves, about people like us, and about me. I welcome your comments.

When I first came to the Zone, I was obsessed with the idea of the Search for Extra Terrestrial Intelligence. That’s why I first posted here, about a decade ago; Larry Klaes, a science writer and reporter who used to contribute here quite frequently turned me on to the place and introduced me to you folks. Larry had just published my very first article in a SETI newsletter he used to edit and he felt I would benefit by chatting with the Zone. He was right.

I’ve always been fascinated by the idea of SETI, I formally studied astronomy as a young man, and I have hung around the fringes of the field all my life, both professionally and as an amateur. I also recognize now that the idea of SETI had a particular resonance with me because it dovetailed neatly with some of my own philosophical and ideological prejudices. I have always felt the universe is a random and chaotic place but that within the constraints of the laws of physics anything is possible. “That which is not forbidden is mandatory.” Life and intelligence, I was convinced, arose naturally in my materialistic universe, and if it happened once here on earth, then surely it had happened somewhere else, and probably many different times in many different ways.

After thinking long and hard about this all my life, I don’t feel any different today. Life arises naturally, it evolves in complexity, and eventually intelligence arises, just as naturally as chlorophyll or hemoglobin. Darwinian evolution and natural selection is as natural and inevitable as the Law of Supply and Demand. We don’t need a God to explain ourselves, nature has no other choice.

We all know the circumstantial evidence. Complex organic molecules arise spontaneously in the most hostile environments, even in the great molecular clouds of deep space. In our own world we find life in the most unlikely environments: deep in the earth’s crust, vents and smokers in oceanic trenches, acidic boiling brines in hot springs. There is scarcely any place on earth where life does not thrive. There is no reason to believe that is not the case throughout the universe. We now know that the universe abounds with environments not that dissimilar from the early earth, and we know from the fossil record life arose on our own planet almost as soon as it cooled off, about 4 billion years ago. We have every reason to believe the universe is crowded with living things. Life is certainly wonderful, but not particularly special.

But that circumstantial evidence all points to single-celled creatures, bacteria and algae, or perhaps loosely organized cooperative colonies of them like stromatolites. Multi-cellular organisms with specialized tissues and organ systems didn’t show up in the fossil record until about a half-billion years ago, in fact, almost all the major phyla of metazoans (plus several that have since gone extinct!) seemed to suddenly appear during the Cambrian Explosion. This suggests that though microbial life is easy, multi-cellular creatures require billions of years of evolution to finally make their appearance. Once it appears, it evolves rapidly, but it does appear to be a bottleneck in evolution. Of course, we only have one data point, the earth, but we have no choice but to base our speculation on what we know.

It appears that multi-cellular life complex enough to support sentience is hard to make, and our one example suggests it takes about 500 million years for it to lead to something more or less like us. We’re talking periods of time within an order of magnitude of the the age of the universe itself. And of course, You can have advanced forms of vertebrates for hundreds of millions of years before you start to see language, tool-making, and symbolic thought. Termites have highly sophisticated and complex societies, but they don’t build spaceships and radio telescopes.

The universe is extravagantly large, and it is old, no doubt there are analogues to us Out There, but they may not be very common. Its not unreasonable to suggest that perhaps the universe is simply not old enough for any two intelligent species to have met yet. You don’t need a Fermi Paradox. All you need is space and time, both of which the cosmos has plenty of.

And of course, there may be highly intelligent and very ancient species out there who simply never developed the technology to make interstellar communication possible. Or perhaps, they were able to travel across the stars, and soon found everything they needed to satisfy their curiosity and ensure their security. Machines and the manipulation of great energy may just be a passing phase in their evolution.

I now read my old articles with a bit of wistfulness and embarrassment. The universe hasn’t changed much in the last few decades, even what I know about it hasn’t changed much. But my understanding has.