Are we alone?

[Boerseun]

Δ life is not inevitable. QED

I would say that it is inevitable, because we're dealing here with an object (the universe) of which one of the parameters is infinity.

 

So, that being the case, if there is even a slight chance of life elsewhere, it is inevitable if the universe is infinite. If life elsewhere is not inevitable, then the universe must be finite.

 

Given the chemical make-up, gravitational conditions et al. of Earth, and the Goldilocks zone we find ourselves in, I would say there's nothing unique about our situation. In other solar systems, some planets will fall outside the Goldilocks zone, some will fall in it. Some will be lucky enough to retain most of their atmospheres and not loose it like Mars, thereby suffocating and freezing any life that might have come to the fore. Some will be unlucky and have enormous acidic atmospheres like Venus and will not be habitable. Some will be unlucky enough to be orbiting a dead star. Some will be frozen. Some will have been ejected by complicated motions in their solar system and will be drifting through interstellar space, frozen to the core.

 

The permutations are endless, and surely only a very small fraction of available configurations will allow life that might be recognizable as such by us.

 

But then, we do have billions of planets to work with.

 

So, yes - I do think that Life Elsewhere is not only possible, but inevitable.

 

Call me a bug-eyed optimist, whatever - I stand by it. But I also believe that with the distances involved, we will most likely never meet any of them, before we disappear as a species. I believe if there ever is any sensible contact to be made, it will be our robotic descendants meeting up with the robotic descendants of an alien species, when both humans and the alien species are long gone. We're talking on the scale of millions of years here, and the only hope that "intelligence" has of ever meeting up with "intelligence" from elsewhere, is if both species rid themselves of this vastly impractical, slow, smelly, inefficient meat-bags we habituate.

 

Thus - as far as humans are concerned, we are alone for all practical purposes.

As far as our potentially intelligent machine-based offspring are concerned, we are not alone - they will have the ability and the time to properly investigate the galaxy and make contact with whoever or whatever they might find out there.

[Turtle]

I would say that it is inevitable, because we're dealing here with an object (the universe) of which one of the parameters is infinity.

 

then you would be wrong. i just gave proof. (not wrong to say what you think mind you; only that what you said is wrong. )

 

Call me a bug-eyed optimist, ...

 

i don't know what else to call you but wrong. a logical fallicy is just that, and trying to qualify it, put lipstick on the pig as it were, well...that is just another logical fallicy.

 

so too is the argument that says the chance of life elsewhere is so remote a possibility that it is virtually impossible, a logical fallicy of the probabilistic argumentation kind. this includes the "life couldn't arise on earth emergently on its own because it looks designed and we've yet seen anything new starting up" argument of theists.

 

the logical argument in support of my assertion of this fallacy is found in Black swan theory.

 

The Black Swan Theory is used by Nassim Nicholas Taleb to explain the existence and occurrence of high-impact, hard-to-predict, and rare events that are beyond the realm of normal expectations. Unlike the philosophical "black swan problem", the "Black Swan Theory" (capitalized) refers only to unexpected events of large magnitude and consequence and their dominant role in history. Such events are considered extreme outliers.

...

The term black swan was a Latin expression — its oldest reference is in the poet Juvenal expression that "a good person is as rare as a black swan" ("rara avis in terris nigroque simillima cygno", 6.165). [1] It was a common expression in 16th century London as a statement that describes impossibility, deriving from the old world presumption that 'all swans must be white', because all historical records of swans reported that they had white feathers [2]. In that context, a black swan was something that was impossible, or near impossible and could not exist. After the discovery of black swans in Western Australia [3] during the 18th century, the term metamorphosed to connote that a perceived impossibility may later be found to exist. Taleb notes that, writing in the 19th century, John Stuart Mill used the black swan logical fallacy as a new term to identify falsification, but only drawing on a London expression.

...

One problem, labeled the ludic fallacy by Taleb, is the belief that the unstructured randomness found in life resembles the structured randomness found in games. This stems from the assumption that the unexpected may be predicted by extrapolating from variations in statistics based on past observations, especially when these statistics are presumed to represent samples from a bell-shaped curve.

Black swan theory - Wikipedia, the free encyclopedia

 

there is logic, and then there is crying & gnashing of teeth.

[Boerseun]

then you would be wrong. i just gave proof.

Sorry, oh venerable and wise Shelley One, but you're wrong. Your proof does not apply, because if you look around you, you will see that the concept of Life is not some hopeful pie-in-the-sky concept that can only be considered to be possible because the universe is infinite etc., etc., etc. - Life has already occurred. We know that in the universe we inhabit, the odds of life occurring at least once is 1 - because hey, here we are!

 

Now, we have to take it one step further, and find out if there is anything special about our situation that might prevent it from happening more than once. And it turns out that there is nothing special about Earth, it's composition, etc.

 

I think the proof you quoted from Wiki, the appeal to probability, applies more to the statement that "somewhere, a microwave oven will successfully mate with a space-bourne pink elephant in ballet slippers and give birth to a microphant, because the universe is infinite" than to "somewhere, the seemingly successful experiment with Life (as seen and studied on Earth) will be repeated".

[Turtle]

Sorry, oh venerable and wise Shelley One, but you're wrong. Your proof does not apply, because if you look around you, you will see that the concept of Life is not some hopeful pie-in-the-sky concept that can only be considered to be possible because the universe is infinite etc., etc., etc. - Life has already occurred. We know that in the universe we inhabit, the odds of life occurring at least once is 1 - because hey, here we are!

 

Now, we have to take it one step further, and find out if there is anything special about our situation that might prevent it from happening more than once. And it turns out that there is nothing special about Earth, it's composition, etc.

 

I think the proof you quoted from Wiki, the appeal to probability, applies more to the statement that "somewhere, a microwave oven will successfully mate with a space-bourne pink elephant in ballet slippers and give birth to a microphant, because the universe is infinite" than to "somewhere, the seemingly successful experiment with Life (as seen and studied on Earth) will be repeated".

 

well, i earlier in the thread pointed out the "1" probability myself (what!? didn't read that? ), and i also linked to an article about these errors made here in using probability. if you can't follow the logic then you can't. those who can't count, don't count. if i get a correction from some more authoritive source, i'll consider it. otherwise, carry on with the speculation. . . .

[Boerseun]

if i get a correction from some more authoritive source, i'll consider it.

Better stay away from those Wiki quotes, then...

[Moontanman]

well, i earlier in the thread pointed out the "1" probability myself (what!? didn't read that? ), and i also linked to an article about these errors made here in using probability. if you can't follow the logic then you can't. those who can't count, don't count. if i get a correction from some more authoritive source, i'll consider it. otherwise, carry on with the speculation. . . .

 

Turtle, i don't see why you have such a difficult time accepting that life is just chemistry that happens anyplace the conditions are correct. Just like iron rusting or or oxygen combining with hydrogen to make water. when the conditions are correct the chemistry of life happens too. Life is also driven to complexity, this not only doesn't defy any rules the rules require it.

 

First 'Rule' Of Evolution Suggests That Life Is Destined To Become More Complex

[Turtle]

Originally Posted by Turtle

if i get a correction from some more authoritive source, i'll consider it.

Better stay away from those Wiki quotes, then... :(

 

well, the wiki is not the "authority" i referred to; in the context that i used it, i refer to "authority" as someone with as much or more formal study of probability & propositional logic as i. the proof is mine; i only sourced wiki as a convenience. do you honesty think "probabilistic argumentation" is a made-up wiki thing? let me disabuse you of that idea. :singer: >> Probabilistic argumentation systems a new way to combine logic with probability

 

Turtle, i don't see why you have such a difficult time accepting that life is just chemistry that happens anyplace the conditions are correct. Just like iron rusting or or oxygen combining with hydrogen to make water.

 

yes i know you don't see it. i intend to show it again though in detail. in short, you are making errors in logic, and when i say "logic" i mean strict symbolic logic, not "common sense".

 

we have several fallacies of probabalistic argumentation going on here, and we will first have to cast each in a proper form. i'm quoting wiki here again because it is convenient, available to everyone, and encyclopedic, but the topic is thousands of years old and expounded widely in many authoritive works. in the vulgar vernacular, if you don't believe me, look it up. alrighty thens, onward at a pace that would make a snail gape in awe. . . . . :singer: :phones:

 

Logic - Wikipedia, the free encyclopedia

Logical form

Logic is generally accepted to be formal, in that it aims to analyse and represent the form (or logical form) of any valid argument type. The form of an argument is displayed by representing its sentences in the formal grammar and symbolism of a logical language to make its content usable in formal inference. If one considers the notion of form to be too philosophically loaded, one could say that formalizing is nothing else than translating English sentences in the language of logic.

 

This is known as showing the logical form of the argument. It is necessary because indicative sentences of ordinary language show a considerable variety of form and complexity that makes their use in inference impractical. It requires, first, ignoring those grammatical features which are irrelevant to logic (such as gender and declension if the argument is in Latin), replacing conjunctions which are not relevant to logic (such as 'but') with logical conjunctions like 'and' and replacing ambiguous or alternative logical expressions ('any', 'every', etc.) with expressions of a standard type (such as 'all', or the universal quantifier ∀). ...

[Moontanman]

I always rescue a turtle when I see one stranded in the middle of a highway, unable to climb the curb due to it's shell. I am beginning to wonder if i am doing the right thing, logically I guess I should let them die since the likely hood of me rescuing any one turtle is more or less 0.

[modest]

Okay, but still...with a large enough sample, like the amount of molecules in my body or - a simpler example - the amount of molecules in a glass of water, strings of heads & tails fade into the background. The molecules in a glass of water move about randomly, from one side of the glass to the other. It is possible (probability > 0) that all of the molecules will, at some point, find themselves on one side of the glass and none on the other. It is the possibility of one moving to the right, as opposed to the left (50%) times the possibility of the next....times the possibility of the very last one.

 

Where the medium is water, I'm not sure. But, in the case of a gas you're spot on. The probability that the gas filled container of volume V₁ will have molecules self-compress to fill only a smaller volume V₂ is:

[math]p=\left( \frac{V_2}{V_1} \right)^N[/math]

where p is the probability and N is the number of molecules. Where the volume is being halved it is as you say: 1/2 (the probability of each independent molecule being on the correct side) times itself as many times as there are molecules.

 

A 1 liter glass (per your example) will hold about 1/22.4 moles (or 2.69 x 10²² molecules) at STP. To look at that glass and find all the molecules on one side would then have a probability of roughly,

[math]p=\left( \frac{1}{2} \right)^{ 10^{22} } \approx 10^{-10^{21.5}}[/math]

which is, of course, unimaginably small (in the literal sense of the word unimaginable). The quote below calls it “vanishing small” and “essentially zero”. But, it is also, as you say "probability > 0". In a strictly mathematical sense, it is not zero. In a practical sense, I think one can treat it that way.

 

It is probably worth noting that this thought experiment does not require quantum effects like the other 'wait an impossibly long amount of time' thought experiment about a person tunneling through a wall. The other interesting aspect is that the event necessarily lowers the entropy of the universe.

 

It's explained well here:

 

It may be disturbing to learn that irreversible processes, such as the spontaneous contraction of a gas or the spontaneous transfer of heat from a cold body to a hot body, are not impossible—they are just improbable. As we have just seen, there is a reasonable chance that an irreversible process will occur in a system consisting of a very small number of molecules; however, thermodynamics itself is applicable only to macroscopic systems, that is, to systems that have a very large number of molecules. Consider trying to measure the pressure of a gas consisting of only 10 molecules. The pressure would vary wildly depending on whether no molecule, 2 molecules, or 10 molecules were colliding with the wall of the container at the time of measurement. The macroscopic variables of pressure and temperature are not applicable to a microscopic system with only 10 molecules.

 

As we increase the number of molecules in a system, the chance of a process occurring in which the entropy of the universe decreases diminishes dramatically. For example, if we have 50 molecules ina a container, the chance that they will all be in the left hand of the container is (1/2)

⁵⁰

≈ 10

^-15

. Thus, if we look at the gas once each second, we could expect to see all 50 molecules in the left half of the volume about once in every 10

¹⁵

seconds or once in every 36 million years! For 1 mole (6 x 10

²³

molecules), the chance that all will end up in half of the volume is vanishing small, essentially zero. For macroscopic systems, then, the probability of a process resulting in a decrease in the entropy of the universe is so extremely small that the distinction between improbable and impossible becomes blurred.

Physics for Scientists and Engineers, Volume 1

 

The wait-time for an event like this exceeds the amount of time we have, the age of existance (~15billion years). I am very comfortable calling 1/2 column glasses of water, or spontaneously disembodied smans, impossible events, even though their possibilities are calculably greater than zero.

 

I think that puts it about right

 

~modest

[modest]

So, that being the case, if there is even a slight chance of life elsewhere, it is inevitable if the universe is infinite. If life elsewhere is not inevitable, then the universe must be finite.

 

I have a hard time thinking that *nothing* in a spatially infinite universe is unique. If something can be unique (and I'm not saying if it can or can't be at this point) then how do we *prove* that life is not like this other unique thing? I don't think it's enough to say:

 

And it turns out that there is nothing special about Earth, it's composition, etc.

 

That statement is inherently non-falsifiable. It can't be a step in a proof because it could never, itself, be proven. In fact, I believe there is a kind of circular logic going on here. The argument goes something like this:

 

1. There is life on earth

2. Therefore the probability of life existing elsewhere is nonzero.

3. The universe is infinite

4. Therefore (2 + 3) life exists elsewhere in the universe.

 

But, in order for 2 to be true we must assume that the conditions on earth are not unique which is the very thing the argument is trying to prove. I guess I'm not so convinced that the existence of one thing in infinite space demands the existence of a second such thing. It may be true in the case of our universe with life, but I don't think we've proven it.

 

Does anyone know if the infinite monkey theorem can be proven that the monkeys *will* create Hamlet, or is it only said that they "probably" will or "almost certainly" will? Is there a philosophy of mathematics expert in the house? :singer:

 

~modest

[Boerseun]

I don't think it's enough to say:

And it turns out that there is nothing special about Earth, it's composition, etc.

That statement is inherently non-falsifiable. It can't be a step in a proof because it could never, itself, be proven.

Not quite. If you take a look at Earth's composition, and you take a spectrometer and look at the stars you will find the same kind of stuff up there. The Earth and our solar system consist of iron, hydrogen, carbon, nitrogen, and a whole host of other stuff. Neighboring solar systems consist of exactly the same stuff - not weirdcraptanium. Some solar systems might have more of this and less of that, but there's nothing special about their mixes, either. And with that being the case, nd with the same laws of physics applying everywhere, yes, I think we can conclusively prove that there is nothing special about Earth. I think it's perfectly well falsifiable. Hop in a spaceship an' go check, why dontcha?

In fact, I believe there is a kind of circular logic going on here. The argument goes something like this:

 

1. There is life on earth

2. Therefore the probability of life existing elsewhere is nonzero.

3. The universe is infinite

4. Therefore (2 + 3) life exists elsewhere in the universe.

 

But, in order for 2 to be true we must assume that the conditions on earth are not unique which is the very thing the argument is trying to prove.

I don't think that's quite right. My argument goes lke this:

 

1. The Earth consist out of the very same stuff (and in roughly the same proportions) as what literally millions of other planets in the Milky Way consist of. Out of those Millions, a fair fraction should have roughly the same size of Earth and be in the goldilocks zone. These conditions have led to Life on Earth.

2. Above conditions are not unique to Earth. We can see this by analysing spectroscopic data, where we find the same elements that appear in our solar system. Based on the numbers of stars and the fact that our home star appears to be very average, planets with Earth's composition, size and density should not be unique. They may not be common, but Earth will definitely not be unique. The conditions that led to life on Earth simply must exist on other planets, too. Of course we don't have hard data with snapshots of happy aliens waving to us, but when we apply statistics to spectroscopic data, at least somewhere out of all the billions of planets a planet or ten must have coalesced with roughly the Earth's composition.

3. The universe is infinite.

4. The above merely increase the odds as applied in (2).

I guess I'm not so convinced that the existence of one thing in infinite space demands the existence of a second such thing. It may be true in the case of our universe with life, but I don't think we've proven it.

I think the only proof that will ever settle this matter is a picture of an alien landing on the White House lawn. I don't think it's a thing that can ever be proven either ways - but the numbers make for a compelling argument, however.

Does anyone know if the infinite monkey theorem can be proven that the monkeys *will* create Hamlet, or is it only said that they "probably" will or "almost certainly" will? Is there a philosophy of mathematics expert in the house?

Well, if you have infinite time at your disposal, you can always wait and see. That particular argument can't be proven either ways either, because of the insertion of the term "infinite". There simly is no ways to execute the experiment! So maybe the flaw lies not so much in the concept itself, but in the methodology? How many monkeys are representative of infinity? Same with the search for alien life, I guess - you can probe each and every single planet in the Milky Way, a project that will keep you busy for billions of years, and not find life. Yet, you still haven't ruled out the possibility of life elsewhere.

 

I think the position of believing life on earth to be unique, is a matter of faith. Allowing the possibility of life elsewhere is merely accepting that the data will never be conclusive - but based on that, we can't exclude the possibility.

[Turtle]

...

I think the only proof that will ever settle this matter is a picture of an alien landing on the White House lawn. I don't think it's a thing that can ever be proven either ways - but the numbers make for a compelling argument, however.

.

 

either you think it's a proper question for symbolic logic, or you do not. if not, then you have no stake in the argument; if so, then you must follow the rules of symbolic logic. restating over & over what you think is not an acceptable response to a formal logical construct.

 

will get to modest's qualification of sman's glass of water this afternoon. :couple:

[Moontanman]

either you think it's a proper question for symbolic logic, or you do not. if not, then you have no stake in the argument; if so, then you must follow the rules of symbolic logic. restating over & over what you think is not an acceptable response to a formal logical construct.

 

will get to modest's qualification of sman's glass of water this afternoon. :couple:

 

Turtle, none of us can prove anything from the one data point we have, a curve cannot be plotted from one data point. We can how ever look out at the rest of the universe and see that there is no reason to assume that the Earth is in any way unique other than we know it has life.

 

Read "Rare Earth" although much of their idea has been refuted to a great extent even they concede the probability of more than one planet in our galaxy with complex life, not many, less than a dozen if I remember correctly. Rare Earth is extremely critical of the idea of lots of "Earths" out there but with 100's of millions of stars in the Milky way even a vanishingly small chance of an Earth like planet with complex life still results in several planets with complex life.

 

One of the ideas they have is that Life probably occurs anywhere it can, bacteria are probably on several planets in our own solar system and if we get off our collective asses it can be falsifiable.

 

The key is if we find life on Mars (bacteria) and maybe the moons of Jupiter or Saturn then we will know life is common, if by some wild chance we find complex life then the question really does become "where the hell are they" Finding complex life in our solar system on a planet other than Earth would be indicative that complex life is common as well.

 

But right now all we can do is speculate, and the argument that the elements of other stars and planets is the same as we have is a powerful argument that the conditions necessary for life does exist on other planets.

[Boerseun]

either you think it's a proper question for symbolic logic, or you do not. if not, then you have no stake in the argument; if so, then you must follow the rules of symbolic logic. restating over & over what you think is not an acceptable response to a formal logical construct.

Either you follow the rules of engagement in debate and read my posts before you reply, or you don't. In which case there's not much I can do about it, I suppose.:couple:

 

Upon re-reading points 1-4 of my previous post, you will see that I'm not merely "restating what I think". I'm presenting an argument. Now address points 1 to 4, if you please.

[Turtle]

Either you follow the rules of engagement in debate and read my posts before you reply, or you don't. In which case there's not much I can do about it, I suppose.:phones:

 

Upon re-reading points 1-4 of my previous post, you will see that I'm not merely "restating what I think". I'm presenting an argument. Now address points 1 to 4, if you please.

 

again, you are mistaken. :shrug: i read your post, i replied logically. you said first probability matters, then you said you didn't think it did. you can't have it both ways.

 

But right now all we can do is speculate, and the argument that the elements of other stars and planets is the same as we have is a powerful argument that the conditions necessary for life does exist on other planets.

 

i never claimed it wasn't possible to find life on other planets; clearly it is. i claimed, and gave supporting arguments and references, it is a logical fallacy to say it's inevitable. :couple:

[Moontanman]

 

i never claimed it wasn't possible to find life on other planets; clearly it is. i claimed, and gave supporting arguments and references, it is a logical fallcay to say it's inevitable. :phones:

 

Life in Solar System? Inevitable, Experts Say : Discovery Space

 

Biology News: Was life on Earth inevitable?

 

 

It's slam dunk, the crowd goes wild! :couple:

[Pyrotex]

Wait! Wait! There's a flag on the field!...