The “sensible anthropic principle” says that certain apparently unusual features of our environment might be explained by selection effects governing the viability of life within a plethora of diverse possibilities, rather than being derived uniquely from simple dynamical principles. Here are some examples of that principle at work.
- Most of the planetary mass in the Solar System is in the form of gas giants. And yet, we live on a rocky planet.
- Most of the total mass in the Solar System is in the Sun. And yet, we live on a planet.
- Most of the volume in the Solar System is in interplanetary space. And yet, we live in an atmosphere.
- Most of the volume in the universe is in intergalactic space. And yet, we live in a galaxy.
- Most of the ordinary matter in the universe (by mass) consists of hydrogen and helium. And yet, we are made mostly of heavier elements.
- Most of the particles of ordinary matter in the universe are photons. And yet, we are made of baryons and electrons.
- Most of the matter in the universe (by mass) is dark matter. And yet, we are made of ordinary matter.
- Most of the energy in the universe is dark energy. And yet, we are made of matter.
- The post-Big-Bang lifespan of the universe is very plausibly infinite. And yet, we find ourselves living within the first few tens of billions of years (a finite interval) after the Bang.
That last one deserves more attention, I think.
But if the lifespan of the universe is infinite, surely the last point is true no matter what the finite interval you choose is. For instance, some other beings 100s of billions of years in the future could also quite rightly say “And yet, we find ourselves living within the very first trillion years (a finite interval) after the Bang.”
Perhaps a better way to look at it is that we are here within the first few generations of stars (although that “few” gets a bit hazy with the short-lived high mass ones), which you need to make the metals etc necessary for us, but we’re here almost as soon as it is possible. (The word “almost” is probably crucial there…)
The “sensible anthropic principle” says that certain apparently unusual features of our environment might be explained by selection effects governing the viability of life within a plethora of diverse possibilities…
No this is the “Denier’s Anthropic principle”, which assumes unobserved possibilities in lieu of the physics that is actually observed, while ignoring many relevant features and more that have been discovered since it was first put forth that make it even stronger.
How convenient.
http://evolutionarydesign.blogspot.com/2006/11/very-strong-anthropic-principle.html
The observed structure of the universe occurs in dramatic contrast to the most natural expectation, (without appealing to “bold attempts” like yours), to produces many fixed balance points are commonly or “coincidentally” pointing directly toward carbon-based life.
The actual evidenced sensibility is that carbon based life is linked to the structure mechanism.
Denial is the only thing that allows the scientific method to supercedes this fact, so the claim of “sensibility” is highly dependent on an intentional distortion of the observation.
Yes, interesting. These points however, concern the features that occur once already given a universe with life-friendly constants. In other words, once we already have a fine structure constant of around 1/137 instead of the “logically” clean value of say, one (sorry, “island,” I couldn’t resist….) and etc., then there are going to be places and ways that life develops. Some of those outcomes are going to be ironic, because life may need special nooks even in a “friendly” universe.
Of course, remember that given a universe with lots of space, mostly gas, etc., then if some small part of it is habitable we can find ourselves there. But that is selection among what already exists, like winning a lottery when you have lots of slot machines. Is our own universe itself a selection among other universes? Does that explain “why it is the way it is” in some way? Perhaps, but there are many ironies. Such universes are so far unobserved and may be literally unobservable, barring some sort of extra-dimensional collision or etc. Also, where does it stop? If universes can have “other laws of physics” then why not ones that aren’t lawful looking at all, that more resemble magical fantasy realms, or heavens and hells, heh heh…
The most stunning point to make, that I still don’t find appreciated is this:
There is, serious as a hear attack, no genuinely logical way to define “existence” above and beyond logical description. IOW, no way to define “matter” aside from the structural descriptions of it, other than appeal (ironically) to metaphysical issues like the realness of our experience, etc. Now you might say, no big deal, since you can imagine just thinking of “the universe” as being pure mathematics/structure (which is evasive since it leaves out experiential qualities, but I digress.) The trouble then is, you have to admit all the other “descriptions” as being equally pseudo-real as well, like it or not. Then, you’ve got a mess on your hands, as I explained before. Sorry, but the whole “cold-blooded materialism” thing is empty posturing, and we don’t even know what “materialism” means when thinking gets beyond sound bites.
PS: DrFish’s comment was very clever. There are however ways to draw statistical conclusions from one’s circumstances, but dealing with infinity is indeed a problem. If you really want to worry about an infinite universe, that is supposed to mean that there are an infinity of happenings just like ours within it, and all the little and big variations, etc. Yikes.
I don’t understand the one-sided infinity thing. Seems to me, once you have a starting point, an eternal future is out the window, for at any point kajillions of years later, the past is finite and the future merely potential.
I think you need an eternal past as well, for the infinity thing to work. But I don’t understand that either.
This is one of those posts that is awesome to read to stoned people.
That’s okay, Neil, I don’t disagree with the relevance of your point, and neither would Sean, I don’t think:
http://arxiv.org/abs/hep-th/0512148
Well, so to contribute more than just metaphysical snark, let me note maybe the first modern-style anthropic prediction, in a sense. It is discussed in pages 250-255 of the opus The Anthropic Cosmological Principle by Barrow and Tipler. Fred Hoyle predicted that there must be a resonance level for the C12 nucleus around 7.7 MeV. It was experimentally confirmed soon after by D. Dunbar and others. Hoyle’s prediction was not motivated by nuclear theory, but by the fact we existed – there wouldn’t have been enough carbon produced by the sun unless that resonance was there. There’s more, involving Oxygen too, and the whole thing shows just how strictly nuclear interactions must be constrained to allow life-friendly mixes of elements. (Island, you should find this interesting – and BTW I am not saying you don’t have a point as self-consistent physics goes. The trouble is, concepts supporting the naturalness of our laws inherently involve some degree of circular reinforcement. If the laws were very different to begin with, then the supportive argument developed from our situation wouldn’t necessarily apply. It’s hard to show self-contradiction of the alternative, from our point of view, and aside from whether you believe in pan-platonism or not.)
I believe I have referenced this before on CV but it seems appropriate to do it once again.
Life could be much “broader” than we imagine somewhat undercutting the “anthropic” reasoning.
http://www.bigear.org/vol1no2/life.htm
We are continuously victims of our perspective.
Elliot
Dammit! I had just been kicking around an idea for a fun little project regarding that last point. It’s such an obvious idea, I’m sure someone will beat me to it now.
Curses…
Yes, Sean’s paper “Is Our Universe Natural?” is fascinating and grand in scope. Just keep in mind though what I said about defining existence as such, and the problem of arguing broadly from a base given us by our circumstances. All the talk of “vacua” and Planck constant etc. implies that something like our universe would have to be the basis, but would it?
OK, here is a “groaner” (?) I thought of years ago, that Allyson can read to her stoned friends (who know a bit of physics and biology):
How did life start?
From atom and eV.
All of our posts are awesome to read to stoned people! You’ve broken the code.
Brian, let me know if you have any good ideas. I’d be happy to ride on your coat tails.
“Most of the planetary mass in the Solar System is in the form of gas giants. And yet, we live on a rocky planet….
.. The post-Big-Bang lifespan of the universe is very plausibly infinite. And yet, we find ourselves living within the first few tens of billions of years (a finite interval) after the Bang.”
Why is most of the above data that has been gathered together, formulated by a rock-bound-species? ..would this factor(a species being rocky planet bound) have a baring on
the available evidence?
Could the sensible anthropic reasoning, be a falsely constrained principle, by fact it is unique to a developed planetary species?
I suppose I am asking if the species local environment, influences the data results?..is there any species external to our solar system, and what effect would this have upon locally gathered data, would the discovery of other data gatherer’s, strengthen or weaken OUR anthropic notions, how credible would the any-anthropic principle be if the Universe were teaming with varying species.. life?
I don’t think that there is any “circular reiforcement” involved with David Gross’ expectation for a “dynamical structure principle”.
But even he ignores the **most apparent** implication that WE ARE IT, and physicists, like Weinberg and Susskind, who do recognize the OBVIOUS anthropic significance, ONLY do so when they can bail on the expected structure mechanism.
In the mean time… it’s still, as Gross says, “the biggest failure of science in the last 20 years”… and will remain so, for as long as these FACTS are willfully ignored by scientists.
I’ve got another one for Sean’s List that Lovelock pointed out… ecobalances, (anthropic balance points), are “self-regulating”.
If the anthropic coincidences are self regulating… then so is the cosmological constant, as well as observed “flatness”, and that minor little detail throws a big monkey-wrench into the projections and assumptions of the cutting-edge who has to ignore this to employ “selection effects” over principle.
Eddington also thought that the cosmological constant version of the general-relativistic field equation expressed the property that the universe was “self-gauging”.
Coincidence?… I don’t think so… but denial supercedes the facts.
How does carbon turn into life ?
Andy Albrecht says [http://arxiv.org/abs/astro-ph/0210527]
To us, the familiar arrow of time is driven by gravitational collapse as it destroys a
homogeneous state. In many models of inflation there are huge regions of the universe
that are undergoing extremely long epochs of exponential expansion. As time progresses
and various imperfections get diluted by the expansion, these regions will asymptotically
approach the high entropy de Sitter state, and by doing so will exhibit increasing entropy.
That is another manifestation of an arrow of time, which is quite different from the one
we are used to which is based on gravitational collapse, not dilution. Is it possible for
other types of creatures to exist that harness the “dilution” arrow of time as effectively as
we harness ours? If the answer is yes, perhaps these creatures will start to evolve as
today’s cosmic acceleration takes over.
Any comments, Sean?
Also:
Most of the people in the universe are religious. And yet, we (i.e. the enlightened scientists) are atheists 🙂
All inteligent people are of the same religion – (they never tell)
daisy rose –
Nobody really understands how carbon turns into life, which is different from how life changes over time. Sure, you have “atom and eV” getting together and getting it on (atoms driven by energy to combine and break away and recombine) but that vague description doesn’t really get to why cells with working DNA come about. It is part of the “cleverness” (how that grates on some here) of the features of the universe, to be so inclined to lead in that direction. There seems such resistance to the idea of it being like that, so that can be the outcome. Sure, that is philosophy and not science, but the whole subject is really philosophy regardless of where you come down.
Dr Who– I think Andy is right, it’s an interesting question, although I don’t have any interesting answers. A related one: could life exist in the atmosphere of an evaporating black hole?
Of course it is Philosophy – Science is philosophy – it cant be otherwise – Yes life can exist in the atmosphere of an evaporating black hole – no one can say other wise –
The post-Big-Bang lifespan of the universe is very plausibly infinite. And yet, I am told by experts (excluding Cryonics buffs and Transhumanists and Nanotechnology True Believers) that I shall die in a small and finite number of years, almost surely at an age less than 137 years.
Most of the volume of the crust of the Earth is inside of Oxygen ions, and yet people have more hydrogen atoms in them than they have oxygen atoms.
Most of the people in the world speak Mandarin, or Arabic, or French, or Hindi, and yet I speak English. Most of the organisms on Earth don’t speak English at all. In fact, most of the mass of life on Earth is not in peoiple, or any kind of mammal, at all.
My name, “Jonathan Vos Post”, contains only 15 letters, and 17 alphanumeric symbols including spaces. And yet almost all sequences of letters, or sequences of alphanumeric symbols including spaces, are much longer than 15 or 17.
My name contains 5 vowels and 10 consonants, for a ration of excatly 1/3 vowels per letter, instead of the “logically” clean value of say, one.
Exactly how do the above facts differ from the astronomical Unusual Features of Our Place In the Universe That Have Obvious Anthropic Explanations?
Probably an obvious thing I am missing, but why can’t life form from dark matter?
Sean: thanks for the reply. When you say “A related one: could life exist in the atmosphere of an evaporating black hole?” are you thinking of radiation from the horizons [cosmological in one case, black hole in the other]? If so, are these situations really similar? I mean, our Sun gives us a source of low-entropy photons, but this only works because the radiation is not isotropic — the Sun is a hot *spot* in the sky. Similarly for the black hole. But radiation from a cosmological horizon would be isotropic. So I guess that a black hole would be a better bet than relying on cosmological horizons!
Tell me if I am talking nonsense….
Forgot to add: the point being that [if we really have a cosmological constant] a cosmological horizon is [unlike an evaporating black hole] something that lasts forever, so life based on it would contradict the claim that life is not infinite in such a spacetime……
Moshe: it can, but sex loses a lot of its fun when you just keep flying through each other.