An uplifting message as we enter the new year, quoted from Edge.org:
We're Not Insignificant After All
Max Tegmark, Physicist, MIT
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.
A few thoughts: when considering the heavy skepticism that the singularity hypothesis receives, it is important to remember that there is a much weaker hypothesis, highlighted here by Tegmark, that still has extremely counter-intuitive implications about our place in spacetime; one might call it the bottleneck hypothesis - the hypothesis that 21st century humanity occupies a pivotal place in the evolution of the universe, simply because we may well be a part of the small space/time window during which it is decided whether earth-originating life will colonize the universe or not.
The bottleneck hypothesis is weaker than the singularity hypothesis - we can be at the bottleneck even if smarter-than-human AI is impossible or extremely impractical, but if smarter-than-human AI is possible and reasonably practical, then we are surely at the bottleneck of the universe. The bottleneck hypothesis is based upon less controversial science than the singularity hypothesis, and is robust to different assumptions about what is feasible in an engineering sense (AI/no AI, ems/no ems, nuclear rockets/generation ships/cryonics advances, etc) so might be accepted by a larger number of people.
Related is Hanson's "Dream Time" idea.
Why does every alien race act the same and try to look invisible? Game theory. They all know that evolution will have produced unacceptable value systems elsewhere in the universe. They all know that they risk losing everything if they come into conflict with a superior hostile power. But a strategy of persistent stealth means that at least a certain amount of value will be achieved. So, they live in the dark matter and they don't advertise their presence by visibly messing with the light matter.
I'm not actually saying this is how it is. But it is a hypothesis (one of many, see below) consistent with all the data we have.
Maybe they pipe their waste heat into supermassive black holes.
Regarding the cosmic distribution of dark matter: On my reading there are two levels of structure inferred. There is a dark matter halo around most galaxies, and then there are filamentary networks on the supergalactic scale. The most common view is that it consists of exotic particles, not in the Standard Model, which gravitate but do not radiate. The filaments formed after the big bang due to gravitational clumping, and in turn seeded the formation of the galaxies from light matter.
If you accept that view, then the dark matter is not light matter with all the light being harvested, as I originally suggested. It's just a separate type of matter which doesn't glow in the first place. So if I want to promote the universal stealth hypothesis, perhaps I should deemphasize the role of dark matter and just emphasize the imperative to be invisible, to blend in against the natural cosmic backdrop.
However, our theories about the dark matter are rather tentative, and if you did assume a significant population of galactic and intergalactic civilizations with a common invisibility imperative, I wonder if that would make it plausible that far more of the dark matter is just light matter being kept dark. I don't know the astrophysical reasoning well enough to judge. But there is an issue here which I don't think astrophysicists and cosmologists have ever systematically considered: if large portions of the universe are already artificial, how would that affect our cosmological theories? A lot of cosmology involves elaborate inferences from data like observable atomic abundances. If that data is systematically skewed by biogenic or technogenic influences, then so are the inferences.
And speaking of tentativeness, and of elaborate inferences, all these future scenarios and cosmological theories (and the idea that most of the universe is destined to be converted to computronium is a cosmological theory) are hypotheses built on hypotheses. I think we are in a realm here where it is not rational to pretend to be Bayesian and assign these hypotheses probabilities. I suspect that the most we should say is that we have a list of qualitative hypotheses, each of which are internally consistent and consistent with the data, and then perhaps a list of increasingly dubious lesser hypotheses, which we can affirm to be unlikely for some reason or other. But it's not as if we even know the extent of the hypothesis space. An important aspect of the situation is that our list of "possible and not obviously unlikely" scenarios may grow at any time.
However, not only do people not adhere to this standard of objectivity, I doubt that it would even be advisable to enforce this as a norm, except reactively, after new hypotheses are invented and advocated enthusiastically, or new turns of argument are constructed. Thus, I was criticizing Tegmark and you for saying these things about the future as if you really do know them to be likely, but then I went and said I preferred my own idea about how everyone is hiding in the dark matter. Well, that was psychologically accurate, but I "preferred" it because it gave me more to think about - the stratagems and counter-stratagems of these hypothetical civilizations, and so forth. On purely epistemic grounds, I see no reason to prefer that scenario over the one you were originally advancing, namely, there are no civilizations or intelligences of cosmic extent already existing in the observable universe. The Great Filter might really be that strong; I don't know; it's consistent with everything I do know, so I must regard it as possible.
However, if we had both adhered to the principle of being agnostic on matters we don't actually know about, this exchange might never have occurred, and certain possibilities might never have been explored and critiqued. Then again, maybe agnosticism is so psychologically difficult that one should not worry about asserting it too much; the challenge will always be to assert it enough to rein in some of the false claims of knowledge which abound everywhere.
Returning to the original scenario, one more thought. It has a rather more pessimistic interpretation: that perhaps our past light-cone contains many examples of civilizations which got this far and were then destroyed. On that view, the odds are actually against us.
P.S. by referring to galactic "wilderness" I didn't imply a nature-loving value system. Wilderness simply means, a region not transformed by technology or civilized management. Wilderness zones may exist for reasons other than being nice. Maybe they only care about certain phenomena or possibilities which simply don't exist here. The more dubious aspect of this idea is not that they let us suffer, but rather that they are letting us develop technologically, to the threshold of being a threat to their own purposes.