For those who think life is rare

[turbo]

For those who think life is rare...

We have had several threads in recent months asking if life should be common or rare in our universe, and if intelligent life should be detectable in our galactic neighborhood. Well, if intelligent life can evolve from more basic forms, we may have to revise our estimates after learning about these pioneers of harsh environments.

http://www.livescience.com/animalworld/050207_extremophiles.html

 

[Danger]

Precisely the basis of my contention that the lack of extraterrestrial life is virtually impossible. And consider that all of these weird beasties share DNA with us. Who's to say where something that's life structure is based upon something entirely different can live?

 

[SpaceTiger]

Well, if intelligent life can evolve from more basic forms, we may have to revise our estimates after learning about these pioneers of harsh environments.

But do you see complex life in those conditions? It's a big stretch to say that the existence of microbes in harsh conditions lends support to the prevalence of intelligent life.

 

[Pengwuino]

What I really want to know is why so many people just assume that when we do find life on other planets, that its going to be a far more advanced society that has broken the laws of physics that we know of today. That there going to be using faster then light travel or communications or some mumbo jumbo like that. What if a good majority of our ideas of the laws of physics are basically correct? What if the reality of the universe is that we really can't effectively communicate faster then the speed of light or even begin thinking about approaching the speed of light for practical space-travel?

I mean itd be a real bummer to find out that the only way we can communicate with a newly found species of intelligent life is through horribly slow (relatively) radio waves. I mean really, after 100 years of broadcasting, how far have we left a mark? Relative to the size of the universe, how far out have our signals reached?

 

[turbo]

But do you see complex life in those conditions? It's a big stretch to say that the existence of microbes in harsh conditions lends support to the prevalence of intelligent life.

The point is that if simple life forms can exist in extremely harsh conditions, life can exist in a lot of places we would not consider capable of supporting life. The Earth has developed a relatively benign climate friendly to oxygen breathing creatures (thanks in great part to the photosynthetic algae in the oceans and the plants on the land) over the ages, but is was not always thus. It is possible the complex life can arise in some prett surprising places, when conditions moderate, similar to what happened on Earth.

On our own planet, we have seen that simple forms of life can develop new capabilities, some of which may simply enhance survivability, but the overall trend seems to be that simple life forms tend to give rise to more complex life forms. If intelligence has any real survival value (and I believe that is the case, although it may backfire on us) I expect that complex life forms will exhibit more and more intelligent behavior as time passes. For these reasons, I believe that life is common, and am optimistic that finding other intelligent life is not as big a long-shot as many believe.

 

[turbo]

What I really want to know is why so many people just assume that when we do find life on other planets, that its going to be a far more advanced society that has broken the laws of physics that we know of today. That there going to be using faster then light travel or communications or some mumbo jumbo like that. What if a good majority of our ideas of the laws of physics are basically correct? What if the reality of the universe is that we really can't effectively communicate faster then the speed of light or even begin thinking about approaching the speed of light for practical space-travel?

I mean itd be a real bummer to find out that the only way we can communicate with a newly found species of intelligent life is through horribly slow (relatively) radio waves. I mean really, after 100 years of broadcasting, how far have we left a mark? Relative to the size of the universe, how far out have our signals reached?

If there is other intelligent life out there, even relatively nearby, we may still be isolated from one another by a number of factors. Here are a few:
1) our lifetimes are short and interstellar distances are great
2) we do not have the technology to travel interplanetary space with any alacrity, much less interstellar space. We are only a few steps removed from strapping gunpowder rockets to our cabins to reach space. The fuel-to-payload ratio is incredibly large.
3) we do not have adequate shielding to protect our travelers from the radiation from solar flares, etc, once we get beyond Earth's Magnetic field

There's only one solution - find Arrakis, mine the spice, feed it to the guildsmen until they mutate into navigators who can "fold" space...problem solved.

 

[SpaceTiger]

On our own planet, we have seen that simple forms of life can develop new capabilities, some of which may simply enhance survivability, but the overall trend seems to be that simple life forms tend to give rise to more complex life forms.

Your logic shows that simple life can thrive in harsh environments and that complex life can arise from simple life. We have evidence that both of those things are true in separate occasions, but not at the same time. If you find fish swimming in lava, let me know. Otherwise, I'd consider this to only be evidence that simple life is common.

 

[Entropy]

Who's to say where something that's life structure is based upon something entirely different can live?

No one really. Just like no one can say live definitely exists on other worlds. We simply don't know enough about biogenesis to make any assumptions.

The point is that if simple life forms can exist in extremely harsh conditions, life can exist in a lot of places we would not consider capable of supporting life. The Earth has developed a relatively benign climate friendly to oxygen breathing creatures (thanks in great part to the photosynthetic algae in the oceans and the plants on the land) over the ages, but is was not always thus. It is possible the complex life can arise in some prett surprising places, when conditions moderate, similar to what happened on Earth.

What people fail to understand is just because life survives in a certain environment doesn't mean it can arise there. For example, just because you find life in the desert doesn't mean it can arise there.

but the overall trend seems to be that simple life forms tend to give rise to more complex life forms.

Not true. On early Earth single celled organisms stayed relatively unchanged for almost two billion years. It's only recently that more complex organisms came to be. It could be construed that the development of complex multicellular organisms was just a fluke. Life doesn't try to become more complicated, it just improves surviviblity whether it be more complicated or not. The simplist life forms on Earth, microbes, are also the most successful.

I expect that complex life forms will exhibit more and more intelligent behavior as time passes.

Again, history does not agree with you. Countless species that exhibited high intelligence compared to other organisms at the time and gone exstinct and less intelligent organisms have taken their places. Intellegence in organisms hasn't been steadly increasing since life began as you might think. Only since the rise of primates has intelligence really taken off, but one group of species that have existed in a geological blink in time doesn't offer ample evidence to your claim. You might also consider whales to support you're claim but I don't it is that convincing. Intelligent pack hunters have existed serveral times in the past, like raptors, and have gone exstinct. Its not that rescent of a development. But it is debatable.

 

[Gold Barz]

"Countless species that exhibited high intelligence compared to other organisms at the time." - Well there you go, you agree that there are/were many species that exhibited high, the more of these creatures are the higher the chance you get of a VERY intelligent species to come out the mix.

I don't know about multi-cellular life being a fluke because they could fill unfilled niches that could not be filled by simpler ones and I think given time that increase in complexity will happen. I am not saying that complex life replaces simple life but more like they exist next to each other, all these organisms are involved in complex networks of competition and cooperation, in ways that make each of the individual species thrive.

I agree with SpaceTiger that the discovery of extremophiles doesn't really mean intelligent life is now thought to be more common than before and could arise from simple life in extreme environments but shows simple life could live in environments we never thought possible.

Read this link > http://pespmc1.vub.ac.be/Papers/ComplexityGrowth.html

 

[Hurricane]

http://www.seti.org/site/pp.asp?c=ktJ2J9MMIsE&b=179074

 

[Gold Barz]

Most of the time I get 50-150 using the equation.

 

[Entropy]

- Well there you go, you agree that there are/were many species that exhibited high, the more of these creatures are the higher the chance you get of a VERY intelligent species to come out the mix.

What are you taking about? You are completely missing what I was trying to say. I was saying that intelligence in life hasn't been steadily increasing.

I don't know about multi-cellular life being a fluke because they could fill unfilled niches that could not be filled by simpler ones and I think given time that increase in complexity will happen.

Well given time, anything is possible, but that doesn't mean it is likely. Evolutionary history says your are wrong. Mircobes survived for 2 billion years without multicellular organisms.

The answer is within yourself...

The Drake equation is horribly incomplete. I got 10e-15 civilizations.

 

[Gold Barz]

"You are completely missing what I was trying to say. I was saying that intelligence in life hasn't been steadily increasing." My point is that life with high intelligence compared to the rest have popped up many a times, I agree it hasnt been "steadily" increasing but it certainly has been increasing, with the fossil record to back me up on that, larger brain sizes, brain to body ratio, etc.

As for the single-celled life to multi-celled life...read this link

http://www.ncbi.nlm.nih.gov/books/bv.fcgi?db=Books&rid=cell.section.61

 

[Danger]

But do you see complex life in those conditions?

My own post was based upon the concept of life, period, not necessarily intelligent or even complex life. There's way too little information available for any determination of that. I do, however, believe that some form of self-sustaining, self-replicating complex molecules are pretty much guaranteed to be out there somewhere. At what point those are considered to be 'alive' is not something that I'm qualified to address.
Nice to see you back in action, Tiger.

 

[Nereid]

It is possible the complex life can arise in some prett surprising places, when conditions moderate, similar to what happened on Earth.

Indeed.

It is possible that I can 'teleport' to Io (from Nereid, of course), via quantum tunnelling; however, it is rather unlikely.

Is turbo-1's "possible" > Nereid's? or <?? What basis is there for making an informed judgement?

On our own planet, we have seen that simple forms of life can develop new capabilities, some of which may simply enhance survivability, but the overall trend seems to be that simple life forms tend to give rise to more complex life forms.

Actually, the overall trend is for bacteria to continue to be the dominant form of life on Earth ... "complexity" is rather difficult to get a handle on, in a way that we can hold a discussion, and there's a good case to be made that all the observed complexity of life on Earth is just a drunkard's walk from the wall of irreducible simplicity.

If intelligence has any real survival value (and I believe that is the case, although it may backfire on us) I expect that complex life forms will exhibit more and more intelligent behavior as time passes.

As has already been pointed out, life on Earth doesn't provide much in the way to support this assertion.

Further, as has already also been pointed out, any case of this kind needs to consider the timescales, and those from the history of life on Earth offer little that is meaningfully generalisable (IMHO), other than "we don't have enough data to make meaningful extrapolations".

 

[turbo]

Quote:
Originally Posted by turbo-1
It is possible the complex life can arise in some prett surprising places, when conditions moderate, similar to what happened on Earth.

Indeed.

It is possible that I can 'teleport' to Io (from Nereid, of course), via quantum tunnelling; however, it is rather unlikely.

Is turbo-1's "possible" > Nereid's? or <?? What basis is there for making an informed judgement?

My point was/is that simple single-celled life can live under conditions that more complex organisms cannot. When conditions moderate to allow more complex creatures to develop, the seeds of life will already be present.

Quote:
On our own planet, we have seen that simple forms of life can develop new capabilities, some of which may simply enhance survivability, but the overall trend seems to be that simple life forms tend to give rise to more complex life forms.

Actually, the overall trend is for bacteria to continue to be the dominant form of life on Earth ... "complexity" is rather difficult to get a handle on, in a way that we can hold a discussion, and there's a good case to be made that all the observed complexity of life on Earth is just a drunkard's walk from the wall of irreducible simplicity.

Yes, bacteria are the most numerous creatures. That's not the point. To see the trend, take the long view: At one time, the only life on Earth was simple, and now, there are complex forms of life filling every available environmental niche, and providing new environmental niches for the simple life-forms to exploit. Unless you believe that complex life arose on Earth full-blown, you must admit that over time, complex creatures have developed from simpler forms and have evolved and differentiated over time.

Quote:
If intelligence has any real survival value (and I believe that is the case, although it may backfire on us) I expect that complex life forms will exhibit more and more intelligent behavior as time passes.

As has already been pointed out, life on Earth doesn't provide much in the way to support this assertion.

Further, as has already also been pointed out, any case of this kind needs to consider the timescales, and those from the history of life on Earth offer little that is meaningfully generalisable (IMHO), other than "we don't have enough data to make meaningful extrapolations".

Let's look at a few instances where intelligence has survival value: 1) Knowing that seeds, properly stored, can be saved and a new crop can be planted and harvested next year. 2) Knowing what time of year the crops should be planted, to take advantage of the best growing season (implies at least a crude calendar). 3. Being able to learn, remember, and convey ideas, so knowledge can be passed on more efficiently. In the case of humans, intelligence has been key to agriculture, cooperative hunting and gathering, and other activities that have allowed us not only to survive, but to inhabit places that are quite inhospitable. It is not unreasonable to assume that complex creatures on other worlds might also face challenges in which natural selection favors intelligence.

No, we do not have any proof of this - it is conjecture only, but I believe we'll find billions of extraterrestrial life-forms (intelligent or not) before you quantum-tunnel from Nereid to Io.

 

[Entropy]

Unless you believe that complex life arose on Earth full-blown, you must admit that over time, complex creatures have developed from simpler forms and have evolved and differentiated over time.

No, you think Dinosaurs were any less complicated than mammals today? You're only support is that humans, the most complex/intelligent of animals, exist now and less complicated/intelligent creatures existed before us, therefore you conclude that all life must strive to become more complicated/intelligent. That doesn't sound like very good reasoning to me.

Let's look at a few instances where intelligence has survival value: ...

No one is saying that intelligence isn't usefull. Plus you're thinking of intelligence late in evolution and it isn't always as simple as creatures gaining the intelligence of humans over night. You see whenever a creature evolves a certain aspect it can also come with a cost. Increased brain mass although it increases intelligence it also increases the amount of nutrition you need, longer gestation period, and reduced number of offspring per birth. Certainly, smarter lions would be favorable, correct? They could come up with more complex hunting strategies and whatnot. So why haven't the fossile records shown that cats' brain sizes (or all animals' brains for that matter) are increasing? Because it isn't that simple. Increasing brain size simply isn't worth the extra nutrition and other consquences. And the same thing goes with +99.9% of the species on Earth.

Sure, some species will increase in intelligence to a point but once cost outweights benifit they will stop. You think whales have been getting any smarter in the last few hundred thousand years? They're at the point where it won't matter how much smarter they are because they already about ten times smarter than their prey.

It is not unreasonable to assume that complex creatures on other worlds might also face challenges in which natural selection favors intelligence.

Well, seeing that +99.9% it isn't favored, I would say it is quite unreasonable. Maybe if more than one intelligent civilizations had evolved on Earth in the last 4.5 billion years I'd be less sceptical.

but I believe we'll find billions of extraterrestrial life-forms (intelligent or not) before you quantum-tunnel from Nereid to Io.

Just so you know I don't think we will ever find extraterrestrial life-forms, ever. Space just isn't as peaceful as people think.

 

[vincentm]

Why don't you think extra terrestrial life won't be ever found?

 

[turbo]

No, you think Dinosaurs were any less complicated than mammals today?

Are you suggesting that dinos are as complex as humans? Humans have the ability to bear their young alive and on the move, and feed the infants from glandular secretions. These might not seem like complexities to you, but they do to me, and they are the most basic features of mammals...there are more.

You're only support is that humans, the most complex/intelligent of animals, exist now and less complicated/intelligent creatures existed before us, therefore you conclude that all life must strive to become more complicated/intelligent. That doesn't sound like very good reasoning to me.

That is not the only support. Do you think that the first birds were as intelligent and sociable as the Macaws and African Greys of today? Not likely. And creatures do not strive to become more intelligent. That is a misapprehension. Creatures become more intelligent when intelligence has a greater survival value than the cost of the trade-offs. It is pure natural selection. Birds with heavier beaks and strong mandibular muscles can break heavier and heavier nuts and eat food that other birds can't exploit. A macaw can eat palm nuts that other birds can't touch. The heavy beaks and muscles were a result of natural selection, not a decision on the part of the macaws. Same with intelligence.

No one is saying that intelligence isn't usefull. Plus you're thinking of intelligence late in evolution and it isn't always as simple as creatures gaining the intelligence of humans over night. You see whenever a creature evolves a certain aspect it can also come with a cost.

I never claimed that intelligence develops overnight in any species, nor that intelligence will benefit every species. I merely pointed out that whenever intelligence has a positive survival value, that the intelligence of complex creatures will tend to improve. This is basic to the process of natural selection.

Sure, some species will increase in intelligence to a point but once cost outweights benifit they will stop. You think whales have been getting any smarter in the last few hundred thousand years? They're at the point where it won't matter how much smarter they are because they already about ten times smarter than their prey.

We don't know how smart whales are. We do know that their communications evolve over very short time periods and show regional "accents". BTW, if you will do a search on the terms "Essex" and "Mocha Dick" you will see that sperm whales are not particularly dumb, and that one whale in particular held a grudge against the ships that whaled in the South Pacific in the early 1800s. He was very well-known amongst the whalers and the military, and he was the basis for a VERY famous novel.

Well, seeing that +99.9% it isn't favored, I would say it is quite unreasonable. Maybe if more than one intelligent civilizations had evolved on Earth in the last 4.5 billion years I'd be less sceptical.

You may have a different definition of intelligence than I do. I can tell you from decades of pet ownership that intelligence has a lot to do with how a creature interacts with its environment. A 2-3 lb ferret, who can grasp and manipulate things with its front paws while sitting upright is WAY smarter than a typical house cat and is pound-for-pound a genius compared with dogs. You should see what happens when a couple of 1.5# female ferrets decide to harrass an otherwise very sharp mixed-breed dog. I gave a couple of ferrets to a friend with a very personable and clever dog and those girls made his life hell until my friend installed a barrier that the girls couldn't get over and gave Gollum a space that only he and the humans could get to.

A racoon is a whole lot smarter and more of a troublemaker than a bobcat. You can see that intelligence is not simply a matter of simple body mass or brain-mass:body-mass ratio. Intelligence is more valuable and more selectable (by survival value) for some species and less so for others. I don't see really smart sharks in our future...they are already as efficient as they need to be without intelligence - did you notice that they have developed teeth to a high art?

Just so you know I don't think we will ever find extraterrestrial life-forms, ever. Space just isn't as peaceful as people think.

We may not ever find extraterrestrial life, but that's because of our own limitations, not because extraterrestrial life does not exist. I will be very surprised if we do not find fossil evidence of past life on Mars, even if it's only lithophiles.

 

[Entropy]

Are you suggesting that dinos are as complex as humans? Humans have the ability to bear their young alive and on the move, and feed the infants from glandular secretions.

I thought it was implied that humans where not included in what I stated as "mammals" seeing how in the same post I referred to humans as the more complex creatures ever on Earth. Sorry if you misunderstood.

Do you think that the first birds were as intelligent and sociable as the Macaws and African Greys of today?

Actually some early forms of birds probably were. Many early birds were social pack hunters with intelligence probably greater than dogs.

And creatures do not strive to become more intelligent. That is a misapprehension. Creatures become more intelligent when intelligence has a greater survival value than the cost of the trade-offs.

Exactly, in your other posts you seem to imply the opposite that intelligence is inevitable given time. This is exactly what we've been trying to tell you from the start.

We don't know how smart whales are.

Yes we do. They are on the same level as great apes.

sperm whales are not particularly dumb

I was saying they were smart.

I can tell you from decades of pet ownership that intelligence has a lot to do with how a creature interacts with its environment.

What's your point? All animals show some intelligence and can manipulate their environment to a certain degree. When we are referring to "intelligent beings" we are talking about beings with the mental capacity close to humans, not dogs or cats.

A 2-3 lb ferret, who can grasp and manipulate things with its front paws while sitting upright is WAY smarter than a typical house cat and is pound-for-pound a genius compared with dogs.

So by you're logic whales must be idiots compared to farrets because they can't manipulate their environment to the degree a ferret can. A ferret simply appears to be more intelligent that a cat or dog because it has more dexterous appendages and is able to mimic human traits more easily. This is a case of physical limitations, not intelligence. You think a dog could pick things up with its paws even it had the intelligence of a human?

I don't see really smart sharks in our future...they are already as efficient as they need to be without intelligence

Actually, sharks are very intelligent animals. They aren't mindless killing machines as the movies would have you believe.

 

[turbo]

If you can back up ANY of these statements, give some references. Natural selection is pretty well-established by now, and you are dismissing it all.

Sharks are very intelligent animals? What the heck? You can't be serious.

 

[Entropy]

Why don't you think extra terrestrial life won't be ever found?

Well, it would be hard for me to explain ever single detail on why life is very very rare in the cosmos, if it exists at all. Primative life might exists, might. But I think complex life is simply out of the question. But I'll explain a few major points that I think people need to take into considerations.

1. People seem to think that where ever there are sun-like stars there could be a stable solar system, regardless of where it is located in a galaxy. Well, this just isn't the case. It is very unlikely that systems closer to the galatic center could be stable for any significate amount of time. Stars are much more clustered together near the center of galaxies and stars frequently fly very close to each other which can destroy planetary orbits, even if they only come within a light-year from one another the gravity from a passing star can send literally billions of asteriods out of stable orbits and send them flying into the system. Their are even theories that asteriods that have hit the Earth in the past traveling from the Oort because other stars disrupted their orbits. Taking this into account it pretty much says that 50%-75% of all sun-like stars won't be stable systems. But at the outer sections of a galaxy, like where our solar system is, will probably be the only place complex organism will be able to survive.

2. Supernovae can be devestating to surrounding systems. Supernovae can literally sterilize planets within hundreds of light-years. Even from light-years away a supernovae explosions can cook the atmospheres and surfaces of planets with deadly radiation killing all complex life as well as most if not all microbes. Even though they happen rarely in our life time, over millions of years they can render many potenial systems uninhabitable.

3. Also, not all galaxies are rich in heavy elements. Life requires lots of heavier elements like carbon, oxygen, etc. Many galaxies just don't have enough heavy elements to form lots of rocky worlds like our own. Although it is possible for rocky planets to form, in these galaxies they are just flukes and the chances that one of these extremely rare rocky worlds to be ideal for life is next to impossible.

4. A big moon. You really need to have one. It stablizes a planets tilt and protects a planet from dangerous asteriod impacts. Earth's moon is an astronomical freak. The chances that such a big moon forming around a comparatively small planet is incrediably small. Earth was hit just right, by just the right size object that a large moon was able to form. The chances of a collision like this hitting a similar planet to Earth, in a stable solar system, in spot in the galaxy, in the right type of galaxy is completely unlikely.

There are also lots of other factors that go against life forming. But I don't feel like going into every little detail on why I don't think extraterrestial life exists.

 

[Entropy]

If you can back up ANY of these statements, give some references. Natural selection is pretty well-established by now, and you are dismissing it all.

What about natural selection? I've stated nothing that contradicts anything about natural selection.

Sharks are very intelligent animals? What the heck? You can't be serious.

For the exception of some bottom-dwelling sharks and other small sharks, most sharks have comparably large brains. Brain to body ratio in sharks is much bigger than just about all fish and is on par with many other complex vertebrates including many mammals. Take the Great White for instance, you may think it is a mindless killing machine. But in fact, they are very observant and selective eaters. They are often very cautious and anylatical about what they eat. Often they often simply bite something they don't recognize just to taste and feel it to see what it is. A shark's nose has many sensors to help it anylze objects and potential prey. More often than not they spit out whatever they bite.

Also sharks like the hammerhead are very social and also exibit unusually high intelligence.

 

[Chronos]

Interesting. But all other arguments aside, is there not a clear tendency [at least on planet earth] that evolution favors intelligence? And given the fairly indisputable fact it has happened here, does it not appear probable it has happened elsewhere in the universe?

 

[SpaceTiger]

And given the fairly indisputable fact it has happened here, does it not appear probable it has happened elsewhere in the universe?

I'd say this is a valid argument for most things, but the anthropic principle muddies the issue a bit...

 

[Chronos]

Hi ST! Good to hear from you again. I'm just making the Copernican argument [or principle of mediocrity, if preferred] - there is no reason to believe there is anything remarkable about our little ball of dirt, or the very mundane star it happens to orbit in this universe.

 

[SpaceTiger]

Hi ST! Good to hear from you again. I'm just making the Copernican argument [or principle of mediocrity, if preferred] - there is no reason to believe there is anything remarkable about our little ball of dirt, or the very mundane star it happens to orbit in this universe.

But you're not talking about the the Earth or its environment, you're talking about intelligent life. Surely the fact that we observe the existence of an intelligent species is biased by the fact that we are that species...

Can you imagine a situation in which we were asking about extraterrestrial intelligence, yet were not intelligent ourselves?

 

[Gold Barz]

I see what turbo-1 is saying, look at the first life on Earth and compare it to life now and you can obviously notice complexity increased over time, I am not sayin all increased in complexity but if you are saying complexity doesn't increase over time then we wouldn't be here and all would be microbal life. With intelligence its different I think but I have read (I don't actually know if this is true) that the fossil record shows that there is a brain increase in many evolutionary lineages and if your prey starts to get smarter than you then you would have to get smarter too, I am not saying increase in intelligence is inevitable I am just saying I don't think its such an "accident". So I think intelligent life out there would be relatively rare.

 

[selfAdjoint]

I see what turbo-1 is saying, look at the first life on Earth and compare it to life now and you can obviously notice complexity increased over time, I am not sayin all increased in complexity but if you are saying complexity doesn't increase over time then we wouldn't be here and all would be microbal life. With intelligence its different I think but I have read (I don't actually know if this is true) that the fossil record shows that there is a brain increase in many evolutionary lineages and if your prey starts to get smarter than you then you would have to get smarter too, I am not saying increase in intelligence is inevitable I am just saying I don't think its such an "accident". So I think intelligent life out there would be relatively rare.

Evolutionists are very much against the idea that there is any "law" of increasing complexity about evolution. Nobody denies that increasing complexity happened, the dispute is whether it was somehow in the cards. Evolutionists say no, it was all random changes and filtering by the environment, and the environment has a large random component too (comet strikes, etc.). So we are back at square one with evolved complexity just as we are with evolved intelligence; we have ONE example of each and can't draw any conclusions about independent venues.

 

[turbo]

Evolutionists are very much against the idea that there is any "law" of increasing complexity about evolution. Nobody denies that increasing complexity happened, the dispute is whether it was somehow in the cards. Evolutionists say no, it was all random changes and filtering by the environment, and the environment has a large random component too (comet strikes, etc.). So we are back at square one with evolved complexity just as we are with evolved intelligence; we have ONE example of each and can't draw any conclusions about independent venues.

Absolutely right. There is no law that drives the evolution of more and more complex lifeforms. Life on Earth (in general) has the ability to pass on genetic material to successive generations sometimes reproducing sexually, sometimes asexually. The critical thing is that the genetic material is passed on - or not. Those creatures best suited to survive pass on more of their genetic materials, and the the creatures less-suited for their environments tend not to thrive, and their genetic lines die out unless they can adopt some adaptive behavior to compensate. This is natural selection, and it is a function of MANY forces, and is not easily nailed down.

Here is a nice link illustrating the power of natural selection, not over centuries, but over just decades.

http://www.pbs.org/wgbh/evolution/library/01/6/l_016_01.html

 

[Chronos]

I don't think many would dispute that environmental pressure plays a central role in evolution. Climate altering events, like ice ages, are especially hard on critters who were most exquisitely tuned to the former habitat. In certain isolated habitats, like oceanic volcanic vents at great depths, there are creatures that have survived for hundreds of millions of years essentially unchanged. On the other hand, the universe is pretty dangerous place. I would be quite surprised if there are any hospitable planets anywhere that have not been traumatized as much, if not more than our own.

But, I would have to admit to being a maverick by mainstream evolutionists. Intelligence is a fairly unique adaptation. It is not driven by the environment, rather it is driven by competition between individuals of the same species, as well as competition with other species within its ecosystem. Smart rabbits produce more rabbits, dumb rabbits produce more wolves. It's pretty much the difference between whose kids you end up feeding at the end of the day. A smart critter gets more bang for the buck out of its natural abilities than its dumb buddies. Once nature evolved brains, it seems inevitable she would experiment with different sizes. The trick is in not going extinct while traveling the long, torturous road to achieving human-like intelligence. It currently appears there are few, if any just like us 'out there' and none so far advanced that their presence is immodestly obvious.

 

[turbo]

So true! Adaptive behavior can trump natural selection, and that's where the value of intelligence shines. We humans are not particularly strong, or fast, or able to stand extremes of heat or cold, but the adaptive behaviors that we have adopted have given us unprecedented geographic range. The Inuit live in climates that would kill most humans without the knowledge and skills passed down from countless generations.

My predeliction to view and photograph astronomical objects in -20 F weather has grown out of my own experience that these bitter nights often have steady skies, and the learned experience that you must emulate the heat-conserving behaviors of ice fisherman and other cold-weather nuts, and then double that, if you expect to keep your eye glued (frozen is a better term) to a guidescope ocular for 20-30 minutes without moving. My wife says that when I observe in the winter, I'm bigger than the Michelin man. I am "relatively" comfortable in an environment in which an unprepared human would perish in short order.

There is no way that a human could be genetically modified to handle short-term extremes like this - the only way to handle the extremes is to adopt adaptive behaviors. Simple organisms can survive extremes in temperature by developing the ability to go into stasis and conserving resources, but complex organisms have had less success with this. Of course, bears can den up for the winter in places where their body heat and the insulation of the den materials can make survival possible, especially if there is a good blanket of snow. A dry cold winter spells death for many bears, though. Natual selection can operate on a DAILY basis, not just across years, decades and centuries.

 

[Gold Barz]

So evolutionists are against the idea of increasing complexity over time? what does sA mean by "its not in the cards" if it wasnt it the cards then why did it happen?

"It currently appears there are few, if any just like us 'out there'" - I don't think that we can say this, atleast not yet, because we currently are still in the dark...way in the dark, as if today you could say that there are no aliens, they don't exist at all because we haven't made contact but I doubt that it will stay that way in a hundred or so years.

 

[turbo]

So evolutionists are against the idea of increasing complexity over time? what does sA mean by "its not in the cards" if it wasnt it the cards then why did it happen?

Let's refine the concept a bit. Evolutionists believe that natural selection ("survival of the fittest" in the popular jargon) will determine which life-forms pass on their genetic material and which will fade or die out. Evolutionists accept that complex critters have evolved from simpler ones, but most of them would not be so nutty as to propose that there is a natural law that favors complexity. They will agree however that organization, cooperation, and differentiation of simple organisms has allowed complex life forms to develop, and that the viability of these more complex life forms (like the simpler organisms preceding them) is determined by environmental factors. This is the basis for the concept of Natural Selection.

Please note: This is not a zero-sum game and there is no clear either-or. A life-form that is in decline can quickly become ascendant if climatic conditions favor it for a generation or two. Likewise, a genetic line that has thrived for a number of years (or much, much longer) can be wiped out by a generation or two of adverse conditions, if the adversity is severe enough.

 

[Chronos]

I would be nutty enough to support the proposition that natural selection favors complexity. In my mind, it is the biological extension of the second law of thermodynamics.

 

[SpaceTiger]

I would be nutty enough to support the proposition that natural selection favors complexity.

As would I, though I think we have to define "natural law" in this discussion, because I wouldn't say that evolution is a fundamental law of nature either. I would reserve that title for the fundamental laws of physics and say that things like evolution (and the corresponding tendency to complexity) are just logical extensions of those physical laws. I don't mean this to diminish the biological sciences, just to clarify the terms of the debate.

In my mind, it is the biological extension of the second law of thermodynamics.

How so? I'm not seeing the analogy.

 

[Nereid]

At the risk of going over the same ground we've all been over, several times already, let me go over some of the same ground we've all been over, to see if this thread has anything new

1. To what extent is 'intelligent, complex life' on Earth the result of processes that are rare or unique?[/color]

We have no other example of 'intelligent, complex life' (or indeed, any other life). Without any other datum, in what way is any answer to this question different from speculation?

2. Do we have good theories on the formation of solar systems ("good" = can produce predictions about 'earth-like planets' with confidence)?[/color]

No.

3. Do we have good observations of earth-like planets in other solar systems?[/color]

No.

4. Can we reliably estimate the frequency of E.L.E.s for solar systems other than our own?[/color]

This is important because there is one set of circumstances that the geological record is very clear on concerning the maladaptability of 'intelligence' - E.L.E.s (thank you, Deep Impact). In mass extinctions, species/genera/families/orders/classes with limited ranges don't survive. Within genera/families/orders/classes, for those with wide ranges, the survivors are nearly always small 'generalists', not big 'specialists'. It would be interesting to see if a case could be made that 'small generalists' and 'intelligence' are not mutually incompatible.

IOW, E.L.E. frequency is a critical factor in the evolution of complex life (at least it is here on Earth - see #1 above). If they're too high (how high?), intelligence just can't get going, no matter how many times complex life gets started.

(what triggers E.L.E.s? Well, we know asteroid and comet impact do; we can be pretty sure that nearby supernovae - and more distant GRBs - could; perhaps close encounters of the stellar/giant molecular cloud/rogue planet kind could too? Perhaps having a Local Group galaxy go 'BL Lac' on us might too? Perhaps there are geophysical causes too?)

To answer the question: No.

5. Are the principle of mediocrity and Occam's Razor 'scientific'?[/color]

No.

These are sometimes used by one side or the other in these sorts of discussions - what is their status wrt providing a scientific answer?

6. Do we understand the key aspects of why 'intelligence' seems to be favoured by evolution (other than for E.L.E.s)?[/color]

No.

For example, the Kingdom Plantae is also 'complex life', yet I doubt anyone would even try to make a case that evolution favours the development of 'intelligence' in plants.

I think I'll stop here ... except to add that several posts in this thread also suffer from a poor appreciation of the timescales (for example, if 'intelligence' is so adaptively favourable, how come only one of the higher primates has a wide range? How come Homo sap. (or was it another Homo species?) went through a population bottleneck?)

 

[SpaceTiger]

5. Are the principle of mediocrity and Occam's Razor 'scientific'?[/color]

No.

These are sometimes used by one side or the other in these sorts of discussions - what is their status wrt providing a scientific answer?

I agree on all points but this one. I don't think something needs to provide a definite answer in order to be scientific. I would say that any scientist who doesn't consider Occam's Razor in evaluating competing theories is a very poor one indeed.

Also, another nitpicky thing. From your definition of "good", we don't have any good theories for planet formation, but I'm not sure it's the best definition to be using. Does the fact that we can't predict exactly when and where a storm will occur mean that we don't have good theories of how they form? If something is chaotic or just sensitive to initial conditions, then a good theory will simply acknowledge its limited predictive power. I strongly suspect that, given what we know about protoplanetary disks, planet formation may indeed be chaotic.

 

[Nereid]

I agree on all points but this one. I don't think something needs to provide a definite answer in order to be scientific. I would say that any scientist who doesn't consider Occam's Razor in evaluating competing theories is a very poor one indeed.

I agree that a strong case for Occam's Razor being part of science (which is, in a nutshell, what scientists *do*) could be made. A further discussion of this would be OT (a topic for HPS, perhaps?), except in one respect: when it comes to humans applying the razor to discussions concerning intelligent, earth-like life, great care must be exercised, to even identify when what seems like an application of the razor is, in fact, narcism or hubris. (somewhat analogous to conflating 'complex life' with Animalia or Mammalia, or picking 'intelligence' out of a million Animalia characteristics as the sole 'trend' to consider).

Also, another nitpicky thing. From your definition of "good", we don't have any good theories for planet formation, but I'm not sure it's the best definition to be using. Does the fact that we can't predict exactly when and where a storm will occur mean that we don't have good theories of how they form? If something is chaotic or just sensitive to initial conditions, then a good theory will simply acknowledge its limited predictive power. I strongly suspect that, given what we know about protoplanetary disks, planet formation may indeed be chaotic.

We're on the same page here (put it down to trying to get it 'right' in but a sentence or two).

So far as this discussion is concerned, a 'good' theory of planetary formation would be one which could predict - with confidence - the liklihood of 'earth-like planets' forming, in a statistical sense (not a deterministic one). IOW, something like "out of 1 million collapsing gas clouds of mass {X} and composition {Y} (and other parameters), at least one 'earth-like planet' will form in 10,000 of them, +/- 30%" (of course, 'earth-like planet' would need to be defined too - mass+composition+rotation rate+timeframe? +range of orbital parameters?? +a 'Moon'?)

 

[SpaceTiger]

when it comes to humans applying the razor to discussions concerning intelligent, earth-like life, great care must be exercised, to even identify when what seems like an application of the razor is, in fact, narcism or hubris.

Unfortunately, the logic we would use to determine whether or not intelligence is common would have to depend on a model of universe creation, which of course doesn't exist. There are many possibilities:

1) Intelligent Design (the kind consistent with science) - No kind of statistical inference could be made about intelligent life. We have to just look and see.
2) One Universe with random laws - Intelligence likely exists elsewhere, by the Copernican principle.
3) Many universes with random laws - We would only see ourselves in a universe in which we could exist. To infer the likelihood of extraterrestrial intelligence, we would have to integrate under the space of possible physics times the density of intelligent civilizations within them to determine the likelihood of us being in a "multi-intelligence" universe. I won't try to guess at what the result would be.
4) Many universes evolving towards intelligence (perhaps it sustains their existence) - Intelligence likely exists elsewhere, since the universe would likely be specifically tailored to giving rise to intelligence.
5) Many universes evolving towards black hole creation - Not sure. Universes that create many black holes would likely also be long-lived universes, but it's not obvious that it would favor the formation of life in any other way.

So far as this discussion is concerned, a 'good' theory of planetary formation would be one which could predict - with confidence - the liklihood of 'earth-like planets' forming, in a statistical sense

My guess is that our first constraint on this will come from the data rather from a rigorous theory. We already have evidence for planets with Earth-order masses around pulsars and perhaps some detections from microlensing. Also, the fact that our solar system formed several planets around an Earth mass is, I think, support for their prevalence.

 

[Nereid]

Unfortunately, the logic we would use to determine whether or not intelligence is common would have to depend on a model of universe creation, which of course doesn't exist. There are many possibilities:
1) Intelligent Design (the kind consistent with science) - No kind of statistical inference could be made about intelligent life. We have to just look and see.
2) One Universe with random laws - Intelligence likely exists elsewhere, by the Copernican principle.
3) Many universes with random laws - We would only see ourselves in a universe in which we could exist. To infer the likelihood of extraterrestrial intelligence, we would have to integrate under the space of possible physics times the density of intelligent civilizations within them to determine the likelihood of us being in a "multi-intelligence" universe. I won't try to guess at what the result would be.
4) Many universes evolving towards intelligence (perhaps it sustains their existence) - Intelligence likely exists elsewhere, since the universe would likely be specifically tailored to giving rise to intelligence.
5) Many universes evolving towards black hole creation - Not sure. Universes that create many black holes would likely also be long-lived universes, but it's not obvious that it would favor the formation of life in any other way.

Shades of the anthropic principle!

And the logic would have to incorporate a great deal more than models of creation!

Here's something that can be fun: MWI (search on MWI in PF ... hundreds of pages and dozens of threads!).

My guess is that our first constraint on this [prevalence of 'earth-like planets' among 'solar' systems] will come from the data rather from a rigorous theory. We already have evidence for planets with Earth-order masses around pulsars and perhaps some detections from microlensing. Also, the fact that our solar system formed several planets around an Earth mass is, I think, support for their prevalence.

I agree; what I was pointing out is that we don't have any significant constraints/guidelines/bases for making estimates ... either theoretical or observational (beyond our own solar system)!

 

[SpaceTiger]

And the logic would have to incorporate a great deal more than models of creation!

Such as? I think reasonable knowledge of the generative model (in this case, the particulars of universe formation) would be enough to do inference. The basic assumption going into the above is that, of all intelligent civilizations in all universes, we have an equal probability of asking this question from the point of view of anyone of them.

 

[Gold Barz]

I think the shortest way to explain evolution is that over time evolution diversifies life...agree?

 

[Nereid]

And the logic would have to incorporate a great deal more than models of creation!

Such as? I think reasonable knowledge of the generative model (in this case, the particulars of universe formation) would be enough to do inference. The basic assumption going into the above is that, of all intelligent civilizations in all universes, we have an equal probability of asking this question from the point of view of anyone of them.

How about models for/of:
- 'intelligence'?
- estimating the 'characteristic time' of 'intelligence'?
- estimating the 'lead time' for 'intelligence' (assuming the universe model(s) are not 'steady state')?
- estimating the 'lifetime' of 'intelligence' (not - necessarily - the same as 'characteristic time'; model-dependent?)?

re 'intelligence', we would need to have a handle on the extent to which it is 'binary' ('intelligence' is either present or not) or not; if 'continuous', or 'can occur in a range of discrete states', then a handle on how all the above would vary, by 'state of intelligence' (or whatever), ...

 

[Entropy]

I think the shortest way to explain evolution is that over time evolution diversifies life...agree?

No. Evolution doesn't inherently cause diversity. Over most of Earth's history life stayed relatively unchanged and did not try to diversify. Evolution only states that if it is favorable for life to diversify or change it will try to do so.

 

[Nereid]

I think the shortest way to explain evolution is that over time evolution diversifies life...agree?

A nice idea ... do the data support it? And if they do support it, in spades, here on Earth, what basis do you have for supposing it operates to the same effect elsewhere?

Some considerations for Earth: to what extent does the 'diversification' depend upon the (multi-dimensional) ranges of environments capable of being occupied by living things? An example: if all the world were deep ocean, what would the time derivative of 'diversity of life' look like? If all the world were ('forever') isolated islands ('islands in the sky' are islands)? If a power-law of islands, subject to a power-law of changes? If our quantum of time were a billion years?

 

[Gold Barz]

" Evolution only states that if it is favorable for life to diversify or change it will try to do so."

Oops, sorry I meant to say this...that it would change if the change was in favor.

 

[SpaceTiger]

re 'intelligence', we would need to have a handle on the extent to which it is 'binary' ('intelligence' is either present or not) or not; if 'continuous', or 'can occur in a range of discrete states', then a handle on how all the above would vary, by 'state of intelligence' (or whatever), ...

The idea was that these models of intelligence would have to be derived from the parameters (i.e. physical laws) of the universe in question, as I specified in item #3. There would not need to be more information, just more work. In some cases, however, I think inference can be done without detailed models (that is, we can use our intuition). In point 1, for example, the answer is very easy -- there's no way for us to infer the probability of extraterrestrial intelligence because the model invokes something not governed by chance. In #2, I think we can just invoke Occam's Razor, since no anthropic selection biases are present. In #3, we would have to derive the things you're describing in detail. #4 is even more biased towards multiple intelligence than #2, so the inference is obvious. Finally, #5 would probably have to be worked out in detail as well.

I'm not suggesting we can get definitive answers, just that we can develop an intuition for what would be probable if we had a generative model with which to work. The issue of priors can be debated -- Do we choose a random species? A random point in time of intelligent life? A random organism? It's not clear. I would still contend, however, that none of the conclusions I've drawn so far are dependent upon that choice.

 

[turbo]

No. Evolution doesn't inherently cause diversity. Over most of Earth's history life stayed relatively unchanged and did not try to diversify. Evolution only states that if it is favorable for life to diversify or change it will try to do so.

We've got to be careful with this. Evolution is not a law or principle that causes change.

1) Live things sometimes change.
2) Sometimes they can pass the change on to successive generations.
3) Sometimes the changes are favorable to the survival of the organism - most probably are either neutral or negative.
4) If the change has survival value for the individual (or aids in the success of reproduction) and can be passed on, the change will express itself in successive generations (presuming the trait is not recessive or poorly-expressed in successive generations).
5) This is Natural Selection.

Evolution does not MAKE organisms change or try to change-it does not exert a force on organisms. Evolution is the observed progression of the development of species and sub-species, and their differentiation. It is entirely driven by Natural Selection. In other words, if the variations in individual creatures are both beneficial to the survival and/or reproductive success of the creature AND can be passed on successfully to successive generations, the improvements in those creatures will become engrained in the species.

As in the study of beak shapes in Darwin's finches, it should be noted that the little variations in individuals can be positive or negative on very short time-scales, due to environmental variations. For instance, dry year, harder drier seeds = positive selection for birds with the types of beaks that can most efficiently gather and process them into usable food.

 

[Chronos]

No. Evolution doesn't inherently cause diversity. Over most of Earth's history life stayed relatively unchanged and did not try to diversify. Evolution only states that if it is favorable for life to diversify or change it will try to do so.

Sometimes semantics create the illusion of disagreement where none of any substance exists. Evolution is a chaotic process. Mutation, which is the physical mechanism behind evolution, is an utterly random event. It happens constantly and evironmental factors, like exposure to radiation or mutagenic material, accelerate it. There is only a microscopic chance that any given mutation will both be advantaqeous and survive long enough to be passed on. Life initially diversified with relatively great speed because there were so many available unfilled niches. Almost any mutatation had a fighting chance at a grub stake. Hence, unfilled niches favor biodiversity. Once, however, all niches are filled, the game changes. Current residents, often by dent of sheer numbers, have the advantage. You must be one lucky mutant to invade their turf. This is where evolution favors specialization [complexity]. A specialist can conquer an existing niche merely by doing one thing better than everyone else. Of course, when the specialist is successful, it has a spillover effect on other niches, making formerly 'perfectly' adapted organisms vulnerable to conquest [hence once again fueling diversity].

The diversity and complexity of life today is merely a group photograph of the latest batch of lottery winners. All we can say with any confidence, given current evidence, is that few of them will be around to boast of their 'success' in another 100 million years.