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Physicist, MIT; Researcher, Precision Cosmology; Scientific Director, Foundational Questions Institute
Physicist, MIT; Researcher, Precision Cosmology

We're Not Insignificant After All

When gazing up on a clear night, it's easy to feel insignificant. Since our earliest ancestors admired the stars, our human egos have suffered a series of blows. For starters, we're smaller than we thought. Eratosthenes showed that Earth was larger than millions of humans, and his Hellenic compatriots realized that the solar system was thousands of times larger still. Yet for all its grandeur, our Sun turned out to be merely one rather ordinary star among hundreds of billions in a galaxy that in turn is merely one of billions in our observable universe, the spherical region from which light has had time to reach us during the 14 billion years since our big bang. Then there are probably more (perhaps infinitely many) such regions. Our lives are small temporally as well as spatially: if this 14 billion year cosmic history were scaled to one year, then 100,000 years of human history would be 4 minutes and a 100 year life would be 0.2 seconds. Further deflating our hubris, we've learned that we're not that special either. Darwin taught us that we're animals, Freud taught us that we're irrational, machines now outpower us, and just last month, Deep Fritz outsmarted our Chess champion Vladimir Kramnik. Adding insult to injury, cosmologists have found that we're not even made out of the majority substance.

The more I learned about this, the less significant I felt. Yet in recent years, I've suddenly turned more optimistic about our cosmic significance. I've come to believe that advanced evolved life is very rare, yet has huge growth potential, making our place in space and time remarkably significant.

The nature of life and consciousness is of course a hotly debated subject. My guess is that these phenomena can exist much more generally that in the carbon-based examples we know of.

I believe that consciousness is, essentially, the way information feels when being processed. Since matter can be arranged to process information in numerous ways of vastly varying complexity, this implies a rich variety of levels and types of consciousness. The particular type of consciousness that we subjectively know is then a phenomenon that arises in certain highly complex physical systems that input, process, store and output information. Clearly, if atoms can be assembled to make humans, the laws of physics also permit the construction of vastly more advanced forms of sentient life. Yet such advanced beings can probably only come about in a two-step process: first intelligent beings evolve through natural selection, then they choose to pass on the torch of life by building more advanced consciousness that can further improve itself.

Unshackled by the limitations of our human bodies, such advanced life could rise up and eventually inhabit much of our observable universe. Science fiction writers, AI-aficionados and transhumanist thinkers have long explored this idea, and to me the question isn't if it can happen, but if it will happen.

My guess is that evolved life as advanced as ours is very rare. Our universe contains countless other solar systems, many of which are billions of years older than ours. Enrico Fermi pointed out that if advanced civilizations have evolved in many of them, then some have a vast head start on us — so where are they? I don't buy the explanation that they're all choosing to keep a low profile: natural selection operates on all scales, and as soon as one life form adopts expansionism (sending off rogue self-replicating interstellar nanoprobes, say), others can't afford to ignore it. My personal guess is that we're the only life form in our entire observable universe that has advanced to the point of building telescopes, so let's explore that hypothesis. It was the cosmic vastness that made me feel insignificant to start with. Yet those galaxies are visible and beautiful to us — and only us. It is only we who give them any meaning, making our small planet the most significant place in our observable universe.

Moreover, this brief century of ours is arguably the most significant one in the history of our universe: the one when its meaningful future gets decided. We'll have the technology to either self-destruct or to seed our cosmos with life. The situation is so unstable that I doubt that we can dwell at this fork in the road for more than another century. If we end up going the life route rather than the death route, then in a distant future, our cosmos will be teeming with life that all traces back to what we do here and now. I have no idea how we'll be thought of, but I'm sure that we won't be remembered as insignificant.