Thermodynamically destined to exist.
Offline From the article
There are exactly 20 standard amino acids — complex molecules that combine to form proteins, which carry out instructions specified by RNA and DNA, its double-stranded and self-replicating descendant.
Ten were synthesized in the famous 1953 Miller-Urey experiments, which modeled conditions believed to exist in Earth's early atmosphere and volcano-heated pools. Those 10 amino acids have also been found in meteorites, prompting debate over their role in sparking life on Earth and, perhaps, elsewhere.
Pudritz's analysis, co-authored with McMaster University biophysicist Paul Higgs and published Monday on arXiv, doesn't settle the former debate, but it does suggest that basic amino acids are even more common than thought, requiring little more than a relatively warm meteorite of sufficient size to form. And that's just the start.
If the observed patterns of amino acid formation — simple acids require low levels of energy to coalesce, and complex acids need more energy — indeed follow thermodynamic laws, then the basic narrative of life's emergence could be universal.
"Thermodynamics is fundamental," said Pudritz. "It must hold through all points of the universe. If you can show there are certain frequencies that fall in a natural way like this, there is an implied universality. It has to be tested, but it seems to make a lot of sense."
Forget Jesus, the stars died so that you could be here
- Lawrence Krauss
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I lost my whole fucking post after accidently hitting the back button. It took an hour to write. I probably should have saved it on a word doc or something. Is there any way to get it back? (I'm not writing it again).
"Physical reality” isn’t some arbitrary demarcation. It is defined in terms of what we can systematically investigate, directly or not, by means of our senses. It is preposterous to assert that the process of systematic scientific reasoning arbitrarily excludes “non-physical explanations” because the very notion of “non-physical explanation” is contradictory.
-Me
Books about atheism
I understand the subtleties of the word. If you look at the entire sub-discussion you are referring to you may understand my point better.
To conclude that the evidence for the extreme ends of the commonality of life are viable enough to produce faith(evidence based) in either direction(common vs uncommon) in effect renders the evidence purely subjective. If evidence is purely subjective then belief is faith (belief with no evidence).
No matter, I'm confident BobSpence1 will clarify his position for us.
I think I get your point, it was also a reference to the sub-discussion with Vastet. But, I'll hold off on further comment right now because...
Indeed.
A lower bound of zero is precisely defined, ie not loose at all.
The upper bound is fuzzier, because, we don't have estimates of the likelihood that any given ETI will be emitting detectable signals in our general direction when we are looking for them. We know that Earth has been emitting a significant amount of radio-frequency energy in an undirected way for 50 years or so, which should be distinguishable from the natural background out to some significant distance, so that gives us one plausible lower end on what to look for. Assumptions about directed signals are a whole different ball-game.
I haven't got the figures on hand - I should look over at the SETI site - but we could certainly set bounds based on various assumptions. If we look at the number of planets observed with enough sensitivity to detect generalized communication signals, we could make a reasonable assumption that the number of planets in the volume of the galaxy encompassed by that survey is zero, and use that to put a figure on the probability that the actual density of planets at such a level of technology is less than that which would predict at least one or more such ETIs in that volume. This is inevitably fuzzy, but hardly meaningless.
Favorite oxymorons: Gospel Truth, Rational Supernaturalist, Business Ethics, Christian Morality
"Theology is now little more than a branch of human ignorance. Indeed, it is ignorance with wings." - Sam Harris
The path to Truth lies via careful study of reality, not the dreams of our fallible minds - me
From the sublime to the ridiculous: Science -> Philosophy -> Theology
Man, I disappear to Prague for 5 days and this is what I miss.
Sorry for not getting back to you on your response OrdinaryClay (for aforementioned reason) but DeludedGod has pretty much covered everything I would have to say about it. I may be a chemist but he's a much more informed scientist than I will ever be, so I'll bow to him on this one.
M
Forget Jesus, the stars died so that you could be here
- Lawrence Krauss
Forget Jesus, the stars died so that you could be here
- Lawrence Krauss
Yes. It was a great meeting. Dawkins brought cookies, and Hitch and I got into an argument about Iraq. He's very pleasant. It could just be the accent. PZ Myers was there talking about the squid revolution. Dennett went on at length about Paisley.
Oh, and we decided we had a mission from god to go out and discover aliens.
"Yes, I seriously believe that consciousness is a product of a natural process. I find that the neuroscientists, psychologists, and philosophers who proceed from that premise are the ones who are actually making useful contributions to our understanding of the mind." - PZ Myers
It is not zero as you have previously stated. The fact that we exist places the lower bound greater then zero, but how much greater is not known.
Yes, very, very fuzzy. If you ever come across any published numbers I'm all ears.
Like I said ... "These bounds are so loosely defined as to be meaningless."
On this one, you and I agree. I think we differ on what we suspect the odds to be, but as for our ability to determine them: we don't have enough information. We know that the organic fundamentals of life are common. We are getting a better idea of how many stars have planets, at least in our neck of the woods; but even there, it's difficult to estimate either the density of planets in our section of the galaxy (other than 'a lot'), or the percentage of those that are earth-like ('one so far'). I'm intentionally discounting life on non-earth-like planets, simply because we have even less data on the possibility of non-earth-like life.
There are just too many unknowns to come up with any real number. By simply varying the estimates of the number of planets orbiting your typical star, you can come up with vastly different numbers, from "one" to "trillions." I suspect there is life all over the universe, simply because the number of suns burning in the universe is unimaginable. But "all over" could mean we're effectively alone, and we'll never find another example of life. If that's the case, we'll never have a valid estimate of the number of life-bearing planets.
That said: we may be able to detect life sooner than I'd hoped.
"Yes, I seriously believe that consciousness is a product of a natural process. I find that the neuroscientists, psychologists, and philosophers who proceed from that premise are the ones who are actually making useful contributions to our understanding of the mind." - PZ Myers
My sympathies; I have done this too many times myself. But no, its gone.
Enlightened Atheist, Gaming God.
Ah, my invite must have got lost in the post.
Forget Jesus, the stars died so that you could be here
- Lawrence Krauss
Uhm... sure. That must be it.
Sorry, I mistyped - the lower bound is precisely 1, as I said earlier in the post, not fuzzy at all.
So your statement that this "places the lower bound greater then zero" is correct - it is 1.
Favorite oxymorons: Gospel Truth, Rational Supernaturalist, Business Ethics, Christian Morality
"Theology is now little more than a branch of human ignorance. Indeed, it is ignorance with wings." - Sam Harris
The path to Truth lies via careful study of reality, not the dreams of our fallible minds - me
From the sublime to the ridiculous: Science -> Philosophy -> Theology
If you mean the amino acids, I never heard a good explanation of why finding these in the wild is any indicator of much. As was said the most popular conjecture is an RNA World.
Obviously this is wrong. I would love to see a citation from any person in SETI any astrobiologist, astronomer or cosmologist who believes to be the case.
WTF is problematic in stating the bleeding obvious that our current sample of the Universe contains one example of high-level intelligence, ie , us, so therefore we know the lower bound on any current estimate of the number of planets/stars hosting intelligent life in the Universe is 1. If SETI had located N confirmed hits, it would be N+1.
Estimating an upper bound would of course involve many assumptions, so it would be inevitably fuzzy, but a very crude, conservative rough estimate would be based on the assumption that SETI had eliminated the possibility of any ETIs in a specific volume of space centered on Earth. Then estimate the minimum likely number of planets in that volume, and the corresponding number for the Galaxy or the Universe as a whole, using the latest data on observations of extra-solar planets. It would then be a straightforward calculation to assign a confidence figure on any assumed total number based on how many hits we would expect to see in our sample volume given such a total. Any number that predicted two or more local hits would be assigned a low value.
Favorite oxymorons: Gospel Truth, Rational Supernaturalist, Business Ethics, Christian Morality
"Theology is now little more than a branch of human ignorance. Indeed, it is ignorance with wings." - Sam Harris
The path to Truth lies via careful study of reality, not the dreams of our fallible minds - me
From the sublime to the ridiculous: Science -> Philosophy -> Theology
The values we are trying to estimate are the lower and upper bound on the probability of an event(ETI) in our population. The population is not our sample of one planet. The population is some set of planets in the Universe. The proper set to use in this is the set of all planets, because what we really want to know is how common life is in the entire Universe.
The set of all planets includes one confirmed hit. Deal with it.
EDIT: Of course, the existence of our one known case does not tell us anything about the a priori probability of intelligent life, apart from it being greater than zero, but then neither would any sample, even a 100% 'sample', tell us anything much without a whole lot of Drake Equation type assumptions.
If we wanted to estimate the probability of intelligence arising per Galaxy, by statistical sampling,we would have to examine a large enough sample of similar galaxies to include some minimum number of hits, especially if the number hits per Galaxy is low.
Similarly, if we want to estimate the probability of life arising in the Universe, we would have to examine a representative sample of similar Universes...
Ideally, we should examine each target at intervals over a time-scale long enough to catch intelligences which didn't last long.
IOW, for practical reasons, we need more than statistical analysis to derive any sort of meaningful estimate of what you seem to be looking for.
And if you are actually asking for an estimate of the probability of life arising from purely natural processes, ie, without divine intervention, there is no way to determine that at all, since we have no way to know what an entity notionally capable of intervening in such a way actually did, or will do, or intends to do. All bets are off if you take seriously the possible existence of a God thing. No knowledge could be really certain.
Favorite oxymorons: Gospel Truth, Rational Supernaturalist, Business Ethics, Christian Morality
"Theology is now little more than a branch of human ignorance. Indeed, it is ignorance with wings." - Sam Harris
The path to Truth lies via careful study of reality, not the dreams of our fallible minds - me
From the sublime to the ridiculous: Science -> Philosophy -> Theology
Just out of curiosity, did you know that the 2nd "law" of themodynamics was shown to be false?
(If memory serves me well you can google up the story on the BBC...written about 4 years ago.)
*Considers looking for the Picard facepalm, decides it isn't worth the time*
The Panda disapproves. Thermodynamics are not "false". How ridiculous.
Enlightened Atheist, Gaming God.
Not really. At best, the experiment showed that order could increase for a short time by an amount greater than allowed by the energy input, but not permanently, ie the effect disappeared over a longer period. This is in accord with the normal applicability of the Law.
There is a significant aspect of statistical probability involved here.
There is a finite probability that all the molecules in a volume of gas could all concentrate in one half of a container, which would clearly be a violation of the Law. Such a situation cannot persist, and the probability is so small for any large collection of gas molecules, so temporary slight increases in order will happen all the time in such systems, but the long term trend is inexorably in accord with the 2nd Law.
Favorite oxymorons: Gospel Truth, Rational Supernaturalist, Business Ethics, Christian Morality
"Theology is now little more than a branch of human ignorance. Indeed, it is ignorance with wings." - Sam Harris
The path to Truth lies via careful study of reality, not the dreams of our fallible minds - me
From the sublime to the ridiculous: Science -> Philosophy -> Theology
If the sample equals the population then it gives you certainty (from a frequentist standpoint) at that moment in time. This would indeed be a very powerful piece of information. It would give you a very accurate estimate of the probability. If it were not for the fact that as the Universe ages the probability may change it would give you the exact probability.
No, it is not dependent on a minimum number of hits, but rather the sample size and the population size.
No, this is not correct. In this case the Universe is the population. So no additional Universes would be needed.
No, you were the one that insisted we could determine upper and lower bounds. My position has been consistently nothing more then: 1) we don't know the probability of ETI, and 2) the evidence is tending toward a lower probability then has been uber optimistically held in the past.
I'm not sure that's true. Maybe for those who have been expecting to find intelligent life in the Centauri system, sure. But the "evidence" that we've collected have really just helped us refine the parameters a little. So far, it's been difficult to detect earth-sized planets around neighboring stars, let alone out to any distance. Our sample space is extremely miniscule. And within that sample space we have one confirmed hit of intelligence in the universe. (Yeah, I know -- selection bias.)
But again, I don't think the question, "Does intelligent life exist in the universe, outside of earth?" is a meaningful question. The probability of that is fairly high, simply because 1) we know it's possible (there's us), and 2) there a fuckload of stars in just our galaxy, and there are a few more galaxies than our own. Just those two facts alone make it fairly likely there's intelligent life somewhere else in the universe.
The real question is, "Is there intelligent life near enough that we might one day discover it?" It'd suck if the universe were teeming with intelligent life, but they were all in Andromeda, going about their space-opera business.
At least, that's how I see it.
"Yes, I seriously believe that consciousness is a product of a natural process. I find that the neuroscientists, psychologists, and philosophers who proceed from that premise are the ones who are actually making useful contributions to our understanding of the mind." - PZ Myers
Be careful what you wish for. Maybe there's an empire blowing up stars one by one and half of Andromeda will go dark in a thousand years when the light gets here.
Note to sticklers: No I did not look up the distance between us and Andromeda, I picked a random number.
Enlightened Atheist, Gaming God.
And I am pointing out that we can set upper and lower bounds, given various assumptions, which is one of the things you do when estimating probabilities in the absence of adequate data.
I stand by my points since I specifically referred to a priori probability of intelligent life arising, rather than estimating the actual population.
Your statement that "It would give you a very accurate estimate of the probability." is clearly incorrect. 'Probability' does not apply if you are simply after the number at the time of 100% sampling, and that is the only thing that would have have precisely determined.
OK so that was not your main point.
Your second point is incorrect and a straw-man, like your totally absurd assertion elsewhere that belief in the existence of ETI is a core tenet of Atheism.
It is clearly religions like Christianity that are most directly concerned by the possibility that ETI may actually exist, since that would be an even bigger blow to the centrality of humanity, special creation, and events on Earth, than Copernicus or Darwin. So it is entirely understandable that believers who actually think about the implications of a confirmed discovery would be actively trying to deny the possibility, just like the anti-evolutionists. Not saying that is your motivation, but your posts and responses are entirely consistent with such an agenda.
Favorite oxymorons: Gospel Truth, Rational Supernaturalist, Business Ethics, Christian Morality
"Theology is now little more than a branch of human ignorance. Indeed, it is ignorance with wings." - Sam Harris
The path to Truth lies via careful study of reality, not the dreams of our fallible minds - me
From the sublime to the ridiculous: Science -> Philosophy -> Theology
This is the kind of optimism which I speak of as unfounded. On the contrary, you ignore the counter evidence and extrapolate based on the two items you seem most comfortable with. The evidence that is accumulating is counter to your faith in large numbers. If we don't discover any in 200 years there will still be people hanging on to your uber optimism .. why ... because "there a fuckload of stars in just our galaxy, and there are a few more galaxies than our own." Notice how your reasoning does not depend on any new information. It just stands no matter what ... seems like faith to me.
Delete duplicate
And I'm pointing out that your "can" is empty because your assumptions are baseless, hence my multiple references to the hopeless optimism.
No, they are not incorrect. Any basic text in probability will explain that the frequentist definition of probability is the long run ratio, and if the sample equals the population there is no longer run. Probability at a given moment in time does matter if the ratio in the population changes with time. This is obviously true, as can be seen by the boundaries. At the singularity and the heat death points the probability is 0.
The evidence (as I pointed out earlier in this thread) is building that life is less probable not more. SETIs failures, along with our better understanding of the planetary conditions needed for life all build negative evidence for the likelihood of life. Discovery of planets around other stars does not bolster the likelihood because this has always been factored into the case of the likelihood for life. The belief that planets were out there has never been doubted. Finding physical evidence for planets is almost meaningless from the standpoint of determining the probability of life.
This is why the skepticism is growing. This skepticism has nothing to do with my being a Christian. The skepticism is due to the evidence.
Yes, as I stated, I am a Christian. No doubts on my part. My position regarding life probabilities sis based on the evidence. This is why non-Christians are skeptical as well. http://www.csicop.org/si/2006-03/seti.html
You really seem to be hell-bent on denying the likelihood of intelligent life somewhere else in the universe, in spite of the evidence (us, tons of other planets, the vastness of the universe, etc). The evidence is not counter to my "faith." (As an aside, this isn't "faith." I don't assume there's other intelligent life out in the universe. I'm not positive there is. I just rationally realize that, since we exist, it is likely there's other life out there.)
You do realize how vast the universe is, right? And you do realize that there is intelligent life in the universe, right? So, we've established that the universe is conducive to intelligent life.
All I've stated is that we've hardly explored the universe at all. We've managed to map out the location of some of the larger planets orbiting stars that are very close to us. And the "evidence" is that more planets exist than was originally estimated. That actually increases the likelihood that there are planets in orbits that would be hospitable to life
The only reason I can see for your denial is that you want humans to be special for some theological reason. I reckon I can understand that. But, from a theological standpoint, what's the point of god creating a universe the size it is just for little ol' us? She's god. She could've created a much smaller universe if we were really that special to her.
Anyway, as I pointed out before, this is a silly argument. We don't have enough data to establish a very good estimate, so all estimates are silly. I personally suspect there's other intelligent life out there, but we'll never see it, so it's all a moot point. But it's a suspicion, not a faith, based on a small application of logic.
"Yes, I seriously believe that consciousness is a product of a natural process. I find that the neuroscientists, psychologists, and philosophers who proceed from that premise are the ones who are actually making useful contributions to our understanding of the mind." - PZ Myers
The more I think about it, the more I realize the difference here is that you think humans are special. This is evidenced in several threads. You really focus on the "uniqueness" of humans, while blithely ignoring the evidence that we are, indeed, not very special at all.
As this is a fundamental disagreement, I can really see no fruit from these discussions. They are fun, certainly; and I enjoy seeing differing viewpoints. I just wanted to point out that our difference is in a base assumption, the uniqueness of humans. Change that assumption in either way, and the argument disappears.
"Yes, I seriously believe that consciousness is a product of a natural process. I find that the neuroscientists, psychologists, and philosophers who proceed from that premise are the ones who are actually making useful contributions to our understanding of the mind." - PZ Myers
It is hypocritical in the extreme for a Christian to criticize us for merely making assumptions which they insist are not well supported by evidence, when Christianity is pretty much entirely based on claims held with certainty with virtually zero evidence to support them, even making a virtue of holding to an important belief ('faith') with zero evidence.
Favorite oxymorons: Gospel Truth, Rational Supernaturalist, Business Ethics, Christian Morality
"Theology is now little more than a branch of human ignorance. Indeed, it is ignorance with wings." - Sam Harris
The path to Truth lies via careful study of reality, not the dreams of our fallible minds - me
From the sublime to the ridiculous: Science -> Philosophy -> Theology
Well, I suppose I could argue that you are hell bent on being overly optimistic. I won't, though. I would rather argue based on the evidence. I'll repeat my position again. I'm not claiming there is no life in the universe. I'm claiming the evidence is building that the probability for life is lower then the optimists believe. Including the optimistic estimates.
I'm curious why you did not respond to my pointing out the fact your argument would not change no matter how much counter evidence existed to it. While, you can argue this is rational, and therefore not faith, I would maintain that if a theist did this they would be scoffed at as being irrational.
I'm not sure what you think I'm denying.
The argument assumes nothing about the uniqueness of humans. No where have I stated or intimated this. You are building a strawman. There is clear evidence that the earth is unique. (Please note that unique does not necessarily mean the only one). It is undeniably special though.
I'm not criticizing. I understand why you believe what you do.
In what way? And what is the evidence? We've barely looked at .000000000000000000000000000000001% of the universe. How can we tell if earth is special in any way?
To what evidence do you refer?
"Yes, I seriously believe that consciousness is a product of a natural process. I find that the neuroscientists, psychologists, and philosophers who proceed from that premise are the ones who are actually making useful contributions to our understanding of the mind." - PZ Myers
You do say our 'beliefs' are unjustified, based on unfounded optimism, and so on, which is criticism.
I think I understand why you hold the position the you appear to, as well.
Favorite oxymorons: Gospel Truth, Rational Supernaturalist, Business Ethics, Christian Morality
"Theology is now little more than a branch of human ignorance. Indeed, it is ignorance with wings." - Sam Harris
The path to Truth lies via careful study of reality, not the dreams of our fallible minds - me
From the sublime to the ridiculous: Science -> Philosophy -> Theology
Oh, I agree the sample size is small(which is an understatement). So I can not quantify how special. This is why I said clearly "not the only one". Since we both know you will dispute anything I say let's start with this "http://books.google.com/books?id=qz7YBLkabzAC&printsec=frontcover&dq=Rare+Earth" It is important to realize that the probability of life is a conditional probability (probability given a proper planet), but that the conditions are independent probabilities (probability of a proper planetary situation). By definition the probability of all the independent events (for the proper planet) occurring together is smaller then each event occurring alone. This smaller joint probability of the independent events make earth special in that sense.
Seems you're overly sensitive.
The earth is not special, humans are not special, and most importantly, you are not special OrdinaryClay.
You have no ground to stand on in any argument I have seen you make here, and constantly try to redefine words to slip out of positions rather than answer any questions.
At least be constructive with your arguments, rather than just starting poor ones and sidestepping questions.
Theism is why we can't have nice things.