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Paul Wally
2013-Jan-09, 10:01 PM
We earthlings have DNA and RNA that stores genetic information, but what other forms of genetic coding could there exist in alien lifeforms? I mean, here on Earth we have DNA macro-molecules, but why should it be the only possible molecule capable of storing genetic information. I guess it depends on how the supposed alien lifeforms evolved and what kind of chemical configurations are more adaptable.

For instance, what if there are lifeforms with non-localized/distributed genetic storage, i.e. the information is stored in a kind of chemical network, perhaps something analogous to a neural net. Such a chemical neural net, would of course have implications for evolution. Would Darwinian evolution still apply in the case of such flexible genes?

I would like to hear your thoughts on this and other alternatives.

Selfsim
2013-Jan-10, 08:33 AM
We earthlings have DNA and RNA that stores genetic information, but what other forms of genetic coding could there exist in alien lifeforms? I mean, here on Earth we have DNA macro-molecules, but why should it be the only possible molecule capable of storing genetic information. I guess it depends on how the supposed alien lifeforms evolved and what kind of chemical configurations are more adaptable.

For instance, what if there are lifeforms with non-localized/distributed genetic storage, i.e. the information is stored in a kind of chemical network, perhaps something analogous to a neural net. Such a chemical neural net, would of course have implications for evolution. Would Darwinian evolution still apply in the case of such flexible genes?

I would like to hear your thoughts on this and other alternatives.Well, I have a few ideas about other alternative chemical storage repositories .. but I'd prefer to steer clear of any 'supposed alien lifeform' speculations .. :)

Ok, so I've mentioned the Belousov-Zhabotinsky reactions before. These reactions are examples of far from equilibirum organic chemistry. The systems are classified as reaction-diffusion systems, and the chemical reaction which causes their visible pattern oscillations, is reduction-oxidation, accompanied by diffusion. The reactions come very close to explaining biological pattern formation via self-organisation, in living systems. Some patterns, such as mussel shell patterns, also mathematically duplicate lab-based reaction-diffusion systems exactly.

Ok, so close study of these chemical systems has also led to some clever engineering, resulting in them being recognised as qualifying as chemical storage units, capable of responding to several different external stimulii. They can also retain a particular complex phase states over the duration of the externally imposed condition. This also qualifies them as being capable of retaining very complex pattern-forming information. In these systems, it is possible to formulate autocatalytic or autoinhibiting reaction steps.

Survival in biological systems requires both self organisation and pattern formation.

The chemicals themselves can vary. Polymer-controlled crystallisation and self-organisation reactions is exhibited in combinations of barium carbonate, potassium bromate, cerium(IV) sulfate, propanedioic acid, and citric acid in dilute sulfuric acid.

The closeness, (in terms of behviours), of these reactions and their roles in formation of structures known to be associated with life, suggests they (or something very similar), may* have been very closely associated with the transition between inert and living chemistries.

Whilst I recognise that your query is not so much about abiogenesis, the overlap of the native functions of these systems and our own biology, is quite remarkable ... if* something like them was involved during some abiogenesis phase, then in our particular instance of it, Evolution has been a flow-on effect.

Hope this idea stimulates some thinking.

* "When in Rome ... do as the Romans do" ... :)

Paul Wally
2013-Jan-10, 11:56 AM
Ok, so I've mentioned the Belousov-Zhabotinsky reactions before. These reactions are examples of far from equilibirum organic chemistry. The systems are classified as reaction-diffusion systems, and the chemical reaction which causes their visible pattern oscillations, is reduction-oxidation, accompanied by diffusion. The reactions come very close to explaining biological pattern formation via self-organisation, in living systems. Some patterns, such as mussel shell patterns, also mathematically duplicate lab-based reaction-diffusion systems exactly.


Interesting. This reminds me of Turing's original work on reaction-diffusion equations to explain morphogenesis (http://en.wikipedia.org/wiki/Morphogenesis).



Ok, so close study of these chemical systems has also led to some clever engineering, resulting in them being recognised as qualifying as chemical storage units, capable of responding to several different external stimulii. They can also retain a particular complex phase states over the duration of the externally imposed condition. This also qualifies them as being capable of retaining very complex pattern-forming information. In these systems, it is possible to formulate autocatalytic or autoinhibiting reaction steps.

I guess old style photography would also count as a simple form of chemical storage. It's all about chemical memory, isn't it? But what is needed for genetics is both memory and replication of memory. How do we define genetic memory? We wouldn't for instance say that something like methane has memory because the methane we can produce in the lab is pretty much the same methane that we can find anywhere else, so methane lacks uniqueness. Genetic information, on the other hand, has to be something unique because if it is something that is readily available in the environment then there is no need to remember how to make it.



The chemicals themselves can vary. Polymer-controlled crystallisation and self-organisation reactions is exhibited in combinations of barium carbonate, potassium bromate, cerium(IV) sulfate, propanedioic acid, and citric acid in dilute sulfuric acid.

The closeness, (in terms of behviours), of these reactions and their roles in formation of structures known to be associated with life, suggests they (or something very similar), may* have been very closely associated with the transition between inert and living chemistries.

Whilst I recognise that your query is not so much about abiogenesis, the overlap of the native functions of these systems and our own biology, is quite remarkable ... if* something like them was involved during some abiogenesis phase, then in our particular instance of it, Evolution has been a flow-on effect.

Hope this idea stimulates some thinking.


You know all these things, yet you seem to have reason to doubt abiogenesis can happen anywhere else. It all rests on chaos theory, I guess.



* "When in Rome ... do as the Romans do" ... :)

That's funny :). I can also play the skeptic if I want to, I just think it's much more interesting to consider the possibilities.

Selfsim
2013-Jan-10, 10:20 PM
Interesting. This reminds me of Turing's original work on reaction-diffusion equations to explain morphogenesis (http://en.wikipedia.org/wiki/Morphogenesis). Yep ..

I guess old style photography would also count as a simple form of chemical storage. It's all about chemical memory, isn't it? But what is needed for genetics is both memory and replication of memory. How do we define genetic memory?This could be just a function of how we're looking at the phenomenon.
If a zebra pattern can be produced from a self-regulating, self-replicating chemical reaction (which functions without any apparent 'memory'), then perhaps the 'memory' is just an illusion which we've imposed, (via our models), when observing the phenomenon(??)

The pattern might appear repeatedly, but the reaction, (and the molecules which produced it, have no such concept of 'memory' .. they're just doin' what they do, and leaving behind something for us to correlate with things we've seen in the past(??)


We wouldn't for instance say that something like methane has memory because the methane we can produce in the lab is pretty much the same methane that we can find anywhere else, so methane lacks uniqueness. Well, I'm not so sure about the analogy .. (but I get the point). Methane's carbon can be measured as having a radio isotopic content, yes? Ie: it 'remembers' its history … or is it just our models correlating the measurement of it, with past histories we've observed in our never ending search for what we've decided, must be a trail of breadcrumbs left behind, specifically for us to draw inferences from?


Genetic information, on the other hand, has to be something unique because if it is something that is readily available in the environment then there is no need to remember how to make it.Who says there's a 'need' to remember anything? (This is intended as a generic question directed at science .. I'm not attempting to single you out, in particular..)

Where exactly, does this concept come from? Where there is no purpose, for 'making it', there is no 'need' for 'memory'(??)

(This is a very subtle, but important distinction).

You know all these things, yet you seem to have reason to doubt abiogenesis can happen anywhere else. It all rests on chaos theory, I guess.Its not so much about Chaos Theory .. that's just another explanation … but the explanation has been developed specifically from these 'types' of dynamic transitional phenomena .. (ie: between phase state changes), whereas predictable inorganic chemistry and thermodynamics law, I think, needs to be somewhat 'relaxed' in order to see through the 'forest', which seems to be evidently applicable to the abiogenesis situation. (Ie: 'horses for courses'). And what this approach brings with it, is sensitivity to initial conditions .. (which makes all the difference).

That's funny :). I can also play the skeptic if I want to, I just think it's much more interesting to consider the possibilities.I like to recognise where my speculation starts and finishes. Its bounded by knowledge, which in many cases, I'm happy to admit, I'm simply not aware of yet .. (Its not bounded however, by opinions and beliefs).
I think we agree on most science aspects … we draw on different philosophical interpretations however, (which can be put aside temporarily, I hope … at least long enough to see the respective perspectives … :) ).

Paul Wally
2013-Jan-11, 12:00 AM
This could be just a function of how we're looking at the phenomenon.
If a zebra pattern can be produced from a self-regulating, self-replicating chemical reaction (which functions without any apparent 'memory'), then perhaps the 'memory' is just an illusion which we've imposed, (via our models), when observing the phenomenon(??)

The pattern might appear repeatedly, but the reaction, (and the molecules which produced it, have no such concept of 'memory' .. they're just doin' what they do, and leaving behind something for us to correlate with things we've seen in the past(??)


I get what you are saying. But I have considered this problem of human interpretation. So let me put it this way: It's not so much about the actual content, because the content can 'mean' anything of course. It's more that there is more information content in some complex configurations relative to simpler configurations. For instance we can know that some macro-molecule carries more information than for instance a methane molecule, even though we don't actually have to attach any meaning to the information content.



Well, I'm not so sure about the analogy .. (but I get the point). Methane's carbon can be measured as having a radio isotopic content, yes? Ie: it 'remembers' its history … or is it just our models correlating the measurement of it, with past histories we've observed in our never ending search for what we've decided, must be a trail of breadcrumbs left behind, specifically for us to draw inferences from?

That would indeed be a form of memory and is the whole basis of C-14 dating. Compare that to for instance a photon or an electron. As far as I know, we cannot determine the age of a photon or an electron, there just isn't that much information contained within these much simpler (more elementary) configurations of matter/energy.




Who says there's a 'need' to remember anything? (This is intended as a generic question directed at science .. I'm not attempting to single you out, in particular..)

Where exactly, does this concept come from? Where there is no purpose, for 'making it', there is no 'need' for 'memory'(??)


It's of course not an actual need, as in a purposive sense. It's more like the sun needs hydrogen in order to shine, or organisms need energy in order to metabolize. It's a functional necessity. In order for a species to continue it is a functional requirement that there is a memory of what the species is, because if there is no such memory the species cannot continue to exist.



Its not so much about Chaos Theory .. that's just another explanation … but the explanation has been developed specifically from these 'types' of dynamic transitional phenomena .. (ie: between phase state changes), whereas predictable inorganic chemistry and thermodynamics law, I think, needs to be somewhat 'relaxed' in order to see through the 'forest', which seems to be evidently applicable to the abiogenesis situation. (Ie: 'horses for courses'). And what this approach brings with it, is sensitivity to initial conditions .. (which makes all the difference).

What difference does sensitivity to initial conditions make to the average global (planet-wide) situation? Take for instance the dynamic phenomena of which you speak. Normally, we would observe such phenomena on a much smaller scale, say within a 1 liter glass vessel. We will then observe a random outcome because of chaos, i.e. everytime we try and repeat the experiment we get a completely different outcome. Now say for instance after we've repeated the experiment a thousand times something interesting happens; self-replicating molecules emerge out of the glass vessel. Now I've looked up. There is about
1,260,000,000,000,000,000,000 liters of water on Earth. I would say the chances of an 'interesting outcome' is significantly increased, because it allows the space of possible outcomes to be thoroughly explored, whereas in the lab we do one experiment with one possible outcome. We do another little experiment with another outcome etc.

Selfsim
2013-Jan-12, 08:49 AM
I get what you are saying. But I have considered this problem of human interpretation. So let me put it this way: It's not so much about the actual content, because the content can 'mean' anything of course. It's more that there is more information content in some complex configurations relative to simpler configurations. For instance we can know that some macro-molecule carries more information than for instance a methane molecule, even though we don't actually have to attach any meaning to the information content. Sure.
Interestingly, our own DNA is interpreted to contain more seemingly superfluous information than 'pertinent'.
Ie: as you say, the size of the molecule is one thing, (when it comes to informational 'potential'), but whether that potential is fully utilised, is another altogether, and how we define 'fully utilised', is another again.

Which would seem to lead away from being too concerned about the potential packing density ... rather, just notice that our own molecule represents a very high potential for this. Does that mean anything in particular?

There is debate about how small (physically and informationally), 'life type molecules 'should' be. I don't think there's much consensus on the matter.

That would indeed be a form of memory and is the whole basis of C-14 dating. Compare that to for instance a photon or an electron. As far as I know, we cannot determine the age of a photon or an electron, there just isn't that much information contained within these much simpler (more elementary) configurations of matter/energy.Yes .. this would be about the 'limits' ... (or that scale thing again).

We should talk about the evolution of 'Threose Nucleic Acids' (TNAs), and the extension of their properties to other so-called Xenonucleic acids (or XNAs). A good kick-off article is here. (http://phys.org/news/2012-04-molecular-alternatives-dna-rna-insight.html) (Its probably more along the lines of what you were looking for in the OP).

It's of course not an actual need, as in a purposive sense. It's more like the sun needs hydrogen in order to shine, or organisms need energy in order to metabolize. It's a functional necessity. In order for a species to continue it is a functional requirement that there is a memory of what the species is, because if there is no such memory the species cannot continue to exist. Hmm .. but the species doesn't know its a 'species', nor does it matter whether it is one or not. The self-replication process just does its thing over and over (with errors, duplications, external influences, etc). The 'functional necessity' might simply be to have an initial starting point .. from thereon, what happens is just what happens. (No memories). I think we're kind of fixated on 'likeness' and 'characteristics in common'. We're pattern matching machines!
Another focus might be almost the opposite .. ie: the diversity in common.
However, clearly like 'species' do persist over certain timeframes ... but they also die out over other timeframes. So, the 'memory' thing is also timescale dependent, eh? (Just sayin').

What difference does sensitivity to initial conditions make to the average global (planet-wide) situation?
Take for instance the dynamic phenomena of which you speak. Normally, we would observe such phenomena on a much smaller scale, say within a 1 liter glass vessel. We will then observe a random outcome because of chaos, i.e. everytime we try and repeat the experiment we get a completely different outcome. Now say for instance after we've repeated the experiment a thousand times something interesting happens; self-replicating molecules emerge out of the glass vessel. Now I've looked up. There is about
1,260,000,000,000,000,000,000 liters of water on Earth. I would say the chances of an 'interesting outcome' is significantly increased, because it allows the space of possible outcomes to be thoroughly explored, whereas in the lab we do one experiment with one possible outcome. We do another little experiment with another outcome etc.I'm not sure I understand your analogy here.
The Belousov-Zhabotinsky reaction can be produced in a 1 liter glass vessel.
It results in oscillating circular patterns created by superstructures of nanoparticles, which are themselves created by self-organisation. The reaction doesn't just take place in a solution, but also in multi-phase systems, and in nanoparticle self-organisation. This discovery is also used to explain biological pattern formation. It doesn't necessarily have to directly involve liquid water, (it can occur in solids, too).
Because the reaction is autocatalytic, it 'manages' the concentration of the reactant/product as it proceeds. The reaction is easily perturbed by external factors which can result in unpredictable pattern behaviours at certain scales. Some of these perturbational effects could, I suppose, happen initially, which could result in no two subsequent reactions proceeding in quite the same way, (at the macro observational scale level).
Beyond this, I'm not quite sure what it might have to do with the scenario you portray, though(??)

Paul Wally
2013-Jan-12, 12:30 PM
Sure.
Interestingly, our own DNA is interpreted to contain more seemingly superfluous information than 'pertinent'.
Ie: as you say, the size of the molecule is one thing, (when it comes to informational 'potential'), but whether that potential is fully utilised, is another altogether, and how we define 'fully utilised', is another again.

It's really because of these and other problems that I'm a bit cautious of pointing out where what information is stored. Information is either everywhere or nowhere in terms of various quantities. If we say DNA stores information then we singling out particular physical systems and discarding others. What about the environment, or the cell membrane. The cell membrane has a selective function and it regulates based on the difference between inside and outside, so I'll say we have some kind of information system there also.



We should talk about the evolution of 'Threose Nucleic Acids' (TNAs), and the extension of their properties to other so-called Xenonucleic acids (or XNAs). A good kick-off article is here. (http://phys.org/news/2012-04-molecular-alternatives-dna-rna-insight.html) (Its probably more along the lines of what you were looking for in the OP).

Thanks. I'll have a look at it.


Hmm .. but the species doesn't know its a 'species', nor does it matter whether it is one or not. The self-replication process just does its thing over and over (with errors, duplications, external influences, etc). The 'functional necessity' might simply be to have an initial starting point .. from thereon, what happens is just what happens. (No memories). I think we're kind of fixated on 'likeness' and 'characteristics in common'. We're pattern matching machines!

The important thing is that we know if something is one thing and not another, because we have defined what 'species', 'replication', 'atom', 'planet' means. And how do you know that we're pattern matching machines without engaging in some pattern matching yourself. Empirical science would be impossible without us recognizing differences and similarities between things.




I'm not sure I understand your analogy here.
The Belousov-Zhabotinsky reaction can be produced in a 1 liter glass vessel.
It results in oscillating circular patterns created by superstructures of nanoparticles, which are themselves created by self-organisation. The reaction doesn't just take place in a solution, but also in multi-phase systems, and in nanoparticle self-organisation. This discovery is also used to explain biological pattern formation. It doesn't necessarily have to directly involve liquid water, (it can occur in solids, too).
Because the reaction is autocatalytic, it 'manages' the concentration of the reactant/product as it proceeds. The reaction is easily perturbed by external factors which can result in unpredictable pattern behaviours at certain scales. Some of these perturbational effects could, I suppose, happen initially, which could result in no two subsequent reactions proceeding in quite the same way, (at the macro observational scale level).
Beyond this, I'm not quite sure what it might have to do with the scenario you portray, though(??)

It's not about the water. It's about the enormous scale ratio between observing chaos in the lab and extrapolating that to the scale of a worldwide ocean. Clearly, if we look at the lab experiment as one experiment, then we have to look at the primordial Earth, not as one such experiments but many many such experiments, and this ratio is important in considering how to apply chaos theory to a planet-wide situation. In a planet-wide situation there is clearly not one initial condition, but countless initial conditions at different locations on the planet. So there is not one random outcome from one initial condition, but countless random outcomes of countless initial conditions, which leads to an average global situation.

Selfsim
2013-Jan-13, 01:35 AM
The important thing is that we know if something is one thing and not another, because we have defined what 'species', 'replication', 'atom', 'planet' means. And how do you know that we're pattern matching machines without engaging in some pattern matching yourself. Empirical science would be impossible without us recognizing differences and similarities between things. Sure .. and I think you've answered your question of me from the other thread. Ie: what definitions does science bring to the table? (Or something along those lines). Science can't proceed without them, I agree.


It's not about the water. It's about the enormous scale ratio between observing chaos in the lab and extrapolating that to the scale of a worldwide ocean. Clearly, if we look at the lab experiment as one experiment, then we have to look at the primordial Earth, not as one such experiments but many many such experiments, and this ratio is important in considering how to apply chaos theory to a planet-wide situation. In a planet-wide situation there is clearly not one initial condition, but countless initial conditions at different locations on the planet. So there is not one random outcome from one initial condition, but countless random outcomes of countless initial conditions, which leads to an average global situation.Well, Ok .. and that's where science's definitions create 'system'. Some random outcomes can be excluded by the definition as not being relevant. Implicit in that paradigm however, is also the observation that somehow, all of that randomness has also resulted in: a single common instance of something we call 'life' (unique); a common (unique) genetic model; a consensus phylogenetic tree of all life (unique); common metabolic processes (unique), etc, ... which also serve as distinctions of improbability within that same paradigm. Chaos addresses both the disorder (randomness) and order (sequencing) simultaneously, and with equal weighting. This can be contrasted with Classical Physics, which typically truncates, (or renormalises), anything which doesn't lead to an output which is the sum of the inputs, (which happens to represent a vast majority of natural 'systems', such as biological ones).

For this reason, its clear that we have to relax the classical definitions of system boundaries .. and when we do this, we address both order and disorder, (or randomness and sequencing), side-by-side, This then leads to the describable form of fractal boundaries, (they suddenly appear), and these then delineate the order from the disorder, (or randomness and sequencing). When we do this, focus shifts to the scale of study and becomes all important, (both temporally and spatially), as does sensitivity to initial conditions.

'Planet' becomes some kind of macro definition, ultimately derived from classical thermodynamics .. ie: the planets are relatively thermodynamically isolated from eachother, but in the 'system' model described above, ie: of a bunch of countless, simultaneous random experiments, we are forced into having to acknowledge the scales on which those experiments are carried out, and the unexpected appearance of self-similarity from amongst them .. and that has nothing to do with a thermodynamically isolated definition .. like 'planet'. The countless 'experiments' should easily occur, right across and beyond that physical boundary, and can extend fully into the domain of Physical Law, (ie: observable behaviours), right across the universe. This is true 'universality' (bounded by observable domains and ubiquitous Physical Law, as opposed to artificially hypothesised arbitrary ones, (like 'planet'), .. which may or may not be relevant to the process which creates life). .. And this is what is under test when it comes to a 'universal model of life'. Science is attempting to find out the pattern repetition at the next level up, (beyond the intuitive thermodynamic boundary definition of planet') … because 'planet' may only be a secondary or tertiary issue, or it may not even be relevant at all (initially). Its all about the process of life, (from start to finish) … not the planet where it is known to exist. We've gotta get away from that limiting concept which we've imposed .. because it seems 'intuitive'.

The analogy here is the introduction of 'Habitability Zone' .. but that model boundary, again ignores the disorder factor, (yet again) and it imposes what is known from only one instance's preferred conditions (ie: Earth-life's), which leads us back around the same loop of thinking .. so we go off looking for more of 'us' and more 'Earths'.

This problem clearly requires a different theoretical modelling approach, which treats with impartiality, observations of both order and disorder, sequencing and randomness, 'probable' and 'improbable', and scales of pattern repetition. By figuring out how those 'things' behave at the abstracted level, we also gain knowledge of what to look for, (and what to 'expect'), from simulations of that theoretical model .. and we already know a lot about those behaviours.

Paul Wally
2013-Jan-13, 07:05 PM
Well, Ok .. and that's where science's definitions create 'system'. Some random outcomes can be excluded by the definition as not being relevant. Implicit in that paradigm however, is also the observation that somehow, all of that randomness has also resulted in: a single common instance of something we call 'life' (unique); a common (unique) genetic model; a consensus phylogenetic tree of all life (unique); common metabolic processes (unique), etc, ... which also serve as distinctions of improbability within that same paradigm. Chaos addresses both the disorder (randomness) and order (sequencing) simultaneously, and with equal weighting. This can be contrasted with Classical Physics, which typically truncates, (or renormalises), anything which doesn't lead to an output which is the sum of the inputs, (which happens to represent a vast majority of natural 'systems', such as biological ones).

What is 'unique'? Unique life on Earth doesn't mean life is unique to Earth. This has nothing to do with 'Classical physics' vs modern physics, perhaps nonlinearity vs linearity, which is found in both classical and modern physical theory. Actually, classical physics is doing just fine on the macroscopic level and chemistry can function autonomously without making use of wave equations of quantum theory. In fact Chaos theory comes from classical physics problems of multi-body dynamics and developed independently of quantum theory.



'Planet' becomes some kind of macro definition, ultimately derived from classical thermodynamics .. ie: the planets are relatively thermodynamically isolated from eachother, but in the 'system' model described above, ie: of a bunch of countless, simultaneous random experiments, we are forced into having to acknowledge the scales on which those experiments are carried out, and the unexpected appearance of self-similarity from amongst them .. and that has nothing to do with a thermodynamically isolated definition .. like 'planet'. The countless 'experiments' should easily occur, right across and beyond that physical boundary, and can extend fully into the domain of Physical Law, (ie: observable behaviours), right across the universe. This is true 'universality' (bounded by observable domains and ubiquitous Physical Law, as opposed to artificially hypothesised arbitrary ones, (like 'planet'), .. which may or may not be relevant to the process which creates life). .. And this is what is under test when it comes to a 'universal model of life'. Science is attempting to find out the pattern repetition at the next level up, (beyond the intuitive thermodynamic boundary definition of planet') … because 'planet' may only be a secondary or tertiary issue, or it may not even be relevant at all (initially). Its all about the process of life, (from start to finish) … not the planet where it is known to exist. We've gotta get away from that limiting concept which we've imposed .. because it seems 'intuitive'.

A planet can be modeled as an open system, with energy in and energy flowing out. Beyond the Earth's atmosphere there is the vacuum of space, so there exists a natural boundary between the Earth and the rest of the universe. There is nothing artificial about the concept of a planet.



The analogy here is the introduction of 'Habitability Zone' .. but that model boundary, again ignores the disorder factor, (yet again) and it imposes what is known from only one instance's preferred conditions (ie: Earth-life's), which leads us back around the same loop of thinking .. so we go off looking for more of 'us' and more 'Earths'.

We are definitely not limited to looking for more 'Earths'. For instance, we can look for life on Titan which, if it exists, will be nothing like Earth life.



This problem clearly requires a different theoretical modelling approach, which treats with impartiality, observations of both order and disorder, sequencing and randomness, 'probable' and 'improbable', and scales of pattern repetition. By figuring out how those 'things' behave at the abstracted level, we also gain knowledge of what to look for, (and what to 'expect'), from simulations of that theoretical model .. and we already know a lot about those behaviours.

As I said in another thread: Randomness plays a key role in self-organization. Without randomness there would be a lack of variety within the system.
I'm going to open a new thread on chaos theory and the 'life-outcome', because we've gone way off topic.

Selfsim
2013-Jan-13, 09:00 PM
What is 'unique'? Unique life on Earth doesn't mean life is unique to Earth. This has nothing to do with 'Classical physics' vs modern physics, perhaps nonlinearity vs linearity, which is found in both classical and modern physical theory. Actually, classical physics is doing just fine on the macroscopic level and chemistry can function autonomously without making use of wave equations of quantum theory. In fact Chaos theory comes from classical physics problems of multi-body dynamics and developed independently of quantum theory. I think you may have misunderstood what I was saying(??)
Life is a unique outcome within your model of abundant randomness. Out of all the randomness your model portrays, we still have one unique model of life on Earth. All life on Earth has been distinguished to be of the same generic type, which makes that model of life a unique one, out of all other possible models which could possibly be distinguished from the randomness in your global model. (We're talking about what we choose to model here, right ...?? ..)

Ok, so the 2nd Law of Classical Thermodynamics states that:

.. the entropy of an isolated system never decreases, because isolated systems spontaneously evolve towards thermodynamic equilibrium—the state of maximum entropy.There are other definitions including the tendency of a system to enter a more probable state, usually described as being to create chaos, from order. This is what I was meaning when I said that the 'uniqueness' of the life model within that system of randomness, was improbable … not that life overall, in the universe, was necessarily 'unique' or 'improbable'.

Order has low probability, and changes to a system which randomise its elements, will be expected to reduce its order significantly. (Ie: shuffling a pack of cards, reduces the chances of getting four aces in four consecutive deals, etc).


A planet can be modeled as an open system, with energy in and energy flowing out. Beyond the Earth's atmosphere there is the vacuum of space, so there exists a natural boundary between the Earth and the rest of the universe. There is nothing artificial about the concept of a planet.Nonetheless, the model comes from the laws of thermodynamics because Earth is obviously isolated, (at everyday macro scales), when viewed from a thermodynamics perspective.

It may not be modelled this way however, when viewed from the perspective of being one in a bunch of planets, confined in a volume limited chunk of the observable universe.

We are definitely not limited to looking for more 'Earths'. For instance, we can look for life on Titan which, if it exists, will be nothing like Earth life.Right .. and which is exactly where Classical Thermodynamics leads us .. (back to where we've come from in the past (completing the loop) ).
What we're trying to do, is to look at all this from another perspective .. ie: that the process, which is speculated to cause life elsewhere in the universe, is not limited by Earth's thermodynamic isolation. How can that condition possibly exist, given that there is nothing at all wrong with Classical Thermodynamics ..?.. We know that it doesn't enable us to see much more than what you say … is there another mainstream theoretical perspective, based in empirical observations, which gives us some other insights?
What are the 'costs' of adopting that different perspective, (if any)?

As I said in another thread: Randomness plays a key role in self-organization. Without randomness there would be a lack of variety within the system.
I'm going to open a new thread on chaos theory and the 'life-outcome', because we've gone way off topic.Randomness needs to be separated from Chaos, though.
(I know you're aware of the differences ..)