Less Wrong is a community blog devoted to refining the art of human rationality. Please visit our About page for more information.

Mitchell_Porter comments on Max Tegmark on our place in history: "We're Not Insignificant After All" - Less Wrong

18 [deleted] 04 January 2010 12:02AM

You are viewing a comment permalink. View the original post to see all comments and the full post content.

Comments (68)

You are viewing a single comment's thread. Show more comments above.

Comment author: Mitchell_Porter 05 January 2010 04:27:24AM 6 points [-]

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.

even the high entropy photons that one would normally expect an information processing entity to excrete as waste heat?

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.