Question for evolutionists

[BradyC]

I'm sure this has been brought up sometime on these forums but I didn't feel like searching. Now all I have is a HS education, so I was hoping all the the brainiacs with PhDs could clear up something for me. It is obvious that human beings have the ability to think and reason. If we are a product of chance (irrationality), how do we make the jump from irrationality to rationality?

[TomCollins]

What makes you think humans are rational?

[benkahuna]

I'm not even really sure what you are asking here.

Are you saying disorder and irrationality are the same thing? Are you asking how the ability to think came from this muck of disorder? If you explain a little more precisely, I can give you a much better answer.

[BradyC]

How does one validate logic if he or she believes they are a product of chance?

Well it depends on your definitions.

What signs of logic are you looking for? The fact we have a language? Animals can communicate. The fact we ponder our existance and have things such as religion? That is where I would like some answers.

Im a stout evolutionist, but I have never really given thought to this. If you look at the evolutionary chain, you've got a ton of lower-thinking life forms, and then boom! us, the acme of evolution, self-realized beings.

How was the jump made?

[theweatherman]

evolution isnt really about chance so much as it is about natural selection. Chance brings about mutations but natural selection is a very rational process that weeds out the negative mutations and strenghtens the positive ones.

Human evolution is a result of rational natural selection and not merely chance.

[bocablkr]

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Well it depends on your definitions.

What signs of logic are you looking for? The fact we have a language? Animals can communicate. The fact we ponder our existance and have things such as religion? That is where I would like some answers.

Im a stout evolutionist, but I have never really given thought to this. If you look at the evolutionary chain, you've got a ton of lower-thinking life forms, and then boom! us, the acme of evolution, self-realized beings .

How was the jump made?

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How can you claim to be a stout evolutionist and then claim there is a jump? Study some more - especially the evolutionary branch from early man upto the present. It is a far more gradual process than you indicate. And there are many other species highly evolved and intelligent (though maybe not self-aware).

Um, have you read an evolutionist text recently? There are as many if's and maybe's in there as all of the world's holy books combined.

So if you have the answer, would you outline it for me?

[benkahuna]

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How does one validate logic if he or she believes they are a product of chance?

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I don't think living systems are about chance at all. I think they are highly ordered systems that follow set principles in order to survive. There's nothing random about how life develops sense organs and the ability to pursue sustenance and favorable environmental conditions. It's the very opposite of chance. This process results from selective pressures that drive the trend that is natural selection.

I don't think humans are necessarily logical. It's more that:

1. We have develop in accordance with the outside world, shaping our nervous system to respond to information in a meaningful way.
2. We are very adapative and creative enabling us to better survive than our nearest living relatives (specieswise).
3. Our abilities result in certain trial and error type behaviors. Such behaviors occur in plenty of other animals (pretty much all with a cortex, capable of learning), we're just way better at them.
4. We work in such a way that we'll have meaningful and accurate interactions with the outside world. Such interactions increase our chances of suriving to reproduce fertile offspring.


I think it's a huge misnomer to conceptualize humans as the first logical living systems or the first emergence of rationality from a sea of randomness.
Everything about humans suggests we're just following one evolutionary trend resulting in:

1. Higher brain:body ratio
2. Great descending control of autonomic function (conscious control of heartbeat, etc.)
3. Great physical coordination in hands
4. A more sophisticated visual system and greater proportions of the brain related to vision
5. Movement toward upright bipedalism

Humans are not unique in either consciousness or self-awareness either. We do, however, appear to be unique in the sophistication of our ability to use language and the ability to consider many abstract concepts like justice, society, etc. The trends I mention are merely one set of trends toward one niche. I'm not suggesting we're some sort of idealized evolutionary endpoint. There's absolutely no reason to believe that we are.

[bocablkr]

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Um, have you read an evolutionist text recently? There are as many if's and maybe's in there as all of the world's holy books combined.

So if you have the answer, would you outline it for me?

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What books are you reading?? If's and maybe's don't correlate to a 'big jump'. We did not just pop out of nowhere on the evolutionary tree. There are many transistional fossils to show the process was quite orderly (even though there are gaps in the record). That does not mean it just jumped from lower species to modern man.

The Evolutionary Tree
Humans are mammals of the Primate order. The earliest primates evolved about 65 million years ago in the geological period known as the Paleocene epoch. They were small-brained, arboreal fruit eaters, similar to modern tree shrews. Primates of the Eocene epoch (55 to 38 million years ago) were similar and ancestral to contemporary tarsiers, lemurs, and tree shrews, and are classified as lower primates or prosimians. During the late Eocene, the higher primates, or anthropoids, developed from prosimian ancestors and, aided by continental drift, diverged into New World (or platyrrhine) and Old World (or catarrhine) monkeys. The branching of Old World monkeys and hominoids apparently occurred in the late Oligocene (38 to 25 million years ago) or early Miocene (25 to 8 million years ago), a time period poorly represented in the fossil record. The lesser apes (gibbons and siamangs) and other hominoid lines diverged about 20 million years ago, while the Asian great apes (the orangutan being the only surviving form) diverged from the African hominoids about 15 to 10 million years ago. Genetic evidence suggests that the ancestral lines of gorillas diverged about 8 million years ago and that chimpanzees and hominids diverged about 5 million years ago.



Hominid Evolution
The earliest known hominids are members of the genus Australopithecus, the earliest of which date to more than 4 million years ago. Unlike other primates, but like all hominids, australopithecines were bipedal. Their crania, however, were small and apelike, with an average cranial capacity of about 450 cc in the gracile species and 600 cc in the robust forms. Australopithecines that have been considered ancestral in the lineage leading to the human genus [censored] include A. afarensis (an important skeleton of which is popularly known as Lucy) and A. africanus. The exact position of these and other early species on the hominid family tree continues to be disputed.

The first member of the genus [censored], a small gracile species known as H. habilis, was present in east Africa at least 2 million years ago. H. habilis was the first hominid to exhibit the marked expansion of the brain (with an average cranial capacity of about 750 cc) that would become a hallmark of subsequent hominid evolutionary history. By about 1.6 million years ago, H. habilis had evolved into a larger, more robust, and larger-brained species known as [censored] erectus. Cranial capacities ranged from about 900 cc in early specimens to 1050 cc in later ones. H. erectus persisted for well over a million years and migrated off the African continent into Asia, Indonesia, and Europe.

Between 500,000 and 250,000 years ago, H. erectus evolved into H. sapiens. Transitional forms between H. erectus and H. sapiens are referred to as archaic H. sapiens. With the exception of H. sapiens neandertalensis (see Neanderthal man), no additional subspecies are recognized. Indeed, some scientists consider Neanderthal a separate species. Archaic H. sapiens changed gradually, becoming somewhat larger, more gracile and larger-brained through time. Cranial capacity, for example, increased from about 1150 cc in early transitional forms to the current world average of just over 1350 cc. By 150,000 years ago in Africa and Asia and 28,000 years ago in Europe (see Cro-Magnon man), the transition to H. sapiens was complete, and fully modern humans became the single surviving hominid species.

[tolbiny]

Most of these arguments boil down to semantics- what is "self aware" or "self realized" anyway? There are animals that show signs of self awareness- ie recognizing themselves in an mirror, elephants "mourning" thier dead, as well as problem solving capabilities of other primates. Hell, watch a squirrel go after a bird feeder, no matter how you design it the little fucker will almoast always get to the food.

[Maddog121]

Thank you. How people have divined randomness from natural selection is beyond me. A selective process is not random.

[purnell]

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us, the acme of evolution

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Why do you make this assumption?

[Trantor]

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Thank you. How people have divined randomness from natural selection is beyond me. A selective process is not random.

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I guess it's because they know the theory is based on random mutations of the genes etc and that whether a particular mutation is better adapted to the the environment the phenotype finds itself in is down to chance.

[Trantor]

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us, the acme of evolution

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Why do you make this assumption?

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He's a closet IDer!

[Rduke55]

Natural selection isn't up to chance.

[Rduke55]

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Thank you. How people have divined randomness from natural selection is beyond me. A selective process is not random.

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I guess it's because they know the theory is based on random mutations of the genes etc and that whether a particular mutation is better adapted to the the environment the phenotype finds itself in is down to chance.

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But the selection of the phenotype isn't chance. that's the big difference.

[Siegmund]

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If we are a product of chance (irrationality), how do we make the jump from irrationality to rationality?

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I would say, no jump is needed; we aren't a "product of irrationality", we are the end result of a natural process.

There is a large family of natural phenomena that are grouped together under the term "self-organizing behavior." If a very slightly inhomogeneous collection of gas and dust is left under the influence of gravity, the dense patches become denser because of their greater attraction, and the thin patches thinner -- making the formation of stars / galaxies / galactic clusters rather than random blobs of hydrogren inevitable, not miraculous. A very similar argument shows that racially mixed neighborhoods would tend to develop into clumps of blacks and clumps of whites even in the absense of racist hatred, because of a tendency for people to desire to live near their own relatives and childhood friends.

Returning to evolution of humans/animals .... such a self-organization argument is used to explain the origin of protein chains and of cells - chemical reactions progressing in such a way as to concentrate certain products in small blobs of the 'primordial soup' rather than freely mixing as one might naively expect them to do.

We can't STOP the world from changing around us, and we can't stop ourselves from continuing to change with it. We concentrate ourselves into cities and states with spaces between them just like the mindless atoms of hydrogren did after the big bang. And our DNA will do what it needs to to sustain its self-replicating behavior.

Individual atoms bounce around 'randomly' in Brownian motion. Their collective behaviour forms patterns so reliably we call the results laws of nature. Individual chains of DNA get their sequences changed 'randomly', but the effect considered over a species as a whole won't look random at all, it will look like a downright purposeful march toward a new species that is better suited in some way to its environment than its predecessor. Individual people, with their 'free will', can 'bounce around the world randomly', but they too can't avoid the fact that the resulting society is going to have a pretty complicated and organized structure to it.

So, to your original question: what jump? "Chance" is just a name for the fact that things look fuzzy when viewed at too high a magnification... when you zoom out and look at the long run, your win rate at poker converges to its true value, and our genes keep on evolving, converging to their ultimate form..... and we'll just have to wait and see what that is, won't we?

[Rduke55]

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converging to their ultimate form

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You had me until this.
There is no ultimate in evolution.

[Trantor]

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Thank you. How people have divined randomness from natural selection is beyond me. A selective process is not random.

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I guess it's because they know the theory is based on random mutations of the genes etc and that whether a particular mutation is better adapted to the the environment the phenotype finds itself in is down to chance.

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But the selection of the phenotype isn't chance. that's the big difference.

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Yep! That's the bit they don't get, apparantly.

[Trantor]

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and our genes keep on evolving, converging to their ultimate form..... and we'll just have to wait and see what that is, won't we?

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Careful, careful! Touch of the ID philosophy seems to be creeping in here!

[tolbiny]

not a bad summery, with the disagreement on Austalopithecus being the ealiest hominids as many recognize ardipithecus ramidus or ardipithecus kadabba as the ealiest know hominids with arguments being made for sahelanthropus being the oldest (quite contraversial). i have it on pretty good authority that a fuller description of Ar ramidus is coming out within the next year or two that will cement its status as bipedal (a nearly 40% complete skelton has been found).

Beyond the strict lineage a lot of times people want to know the why behind it so i thought i might toss out one of the more current theories.

7-8 million years ago (my) the ancestors of the great apes (chimps, gorillas, orangutangs and humans) were widespread throughout europe, asia and africa, they were some of the most prolific groups of mammels ever. At some point around 7 my the great apes began an extinction process that continues to this day, because of some change in geology, weather or predation (or any number of factors) infant mortality began to rise. Up unitil this point male great apes had little to no involvement in feeding/rearing their young. One group of the great apes (the hominids) began participating in their offsprings development and feeding which allowed for a higher percentage of thier own children to make it to a reproductive age- and hence could pass their genes along till the next generation. one of the major adaptations that allowed this was bipedalism, which freed the hominids hands for carrying food back to nursing and pregnant females. This bipedalism in males is also shown in females- and at this point hominids became the only striding bipedal animals on the planet. Walking upright allowed for another adaptation in females- that is the widening of the birth canal. Mammels brain to body ratio is limited by the size of the birth canal, for if the head is to large there will be complications in birth (it is true that humas have many more probliems in giving birth than any other mammel) as the head tries to pass. "Lucy"- the famous A aferensis stil had a primitive birth canal around 4 my. around 3 my the birth canal started to widen and become more oval and this has allowed for brain size to quadrupal from about 3my to around 300,000 years ago when humas hit a "wall" in brain size.

[Siegmund]

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converging to their ultimate form

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You had me until this.
There is no ultimate in evolution.

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If the amount of mass/energy in the universe is finite, there is most assuredly a limit beyond which more complicated structures can't evolve - every increase in local complexity has to be paid for by releasing heat or by increasing entropy somewhere else.

In the simpler case of using genetic algorithms to solve numerical optimization problems, you may allow the solutions to continue evolving forever, but the rate of improvement declines to nil as you approach the optimal solution. I think it's an open question whether arriving at a "perfect life form" or running out of energy will be the cause of evolution eventually grinding to a halt. I will leave that one to the philosophers.

[Rduke55]

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converging to their ultimate form

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You had me until this.
There is no ultimate in evolution.

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If the amount of mass/energy in the universe is finite, there is most assuredly a limit beyond which more complicated structures can't evolve - every increase in local complexity has to be paid for by releasing heat or by increasing entropy somewhere else.

In the simpler case of using genetic algorithms to solve numerical optimization problems, you may allow the solutions to continue evolving forever, but the rate of improvement declines to nil as you approach the optimal solution. I think it's an open question whether arriving at a "perfect life form" or running out of energy will be the cause of evolution eventually grinding to a halt. I will leave that one to the philosophers.

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There's a LOT wrong with this line of reasoning.
There's no room for talk of "improvement" towards the "ultimate" in evolution
More "complex" is not necessarily better
And it's not more "complicated" that I'm talking about - I'm talking about different.

Way too many quotation marks

[bearly]

one of my favorite professors used to jerk our chains by saying; 'yes, god created man thru the process of evolution.".............b

[benkahuna]

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But the selection of the phenotype isn't chance. that's the big difference.

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The genotype is more important as it is heritable. The phenotype does change in a on-random way in response to environmental conditions so you are correct that its selection is not based strictkly on chance, but that's not the most important point to make here.

[Siegmund]

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There's no room for talk of "improvement" towards the "ultimate" in evolution

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You can use different words if you prefer. A niche is a local maximum of a fitness function. A selection pressure is something which results in the fitter genes being passed on in preference to the less fit, and acts over time to move the species along the gradient of a fitness function. Speciation is possible near saddle points of a fitness function.

Do you find it strange that I use the word "improvement" (relative to whatever measure of fitness) to describe change in response to selection pressure?

I don't know how you can talk about evolution and NOT be talking about progress towards some theoetical optimum.

Some functions in some spaces (including all functions continuous on closed domains) have global maxima, and some others approach easily described singularities. Do you find it strange I want a name for the set of places a system can wind up if it is given infinitely long to optimize? (it doesn't have to be a unique limiting species, and, as I said before, we might never get there even if there is.)

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More "complex" is not necessarily better
And it's not more "complicated" that I'm talking about - I'm talking about different.


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This is true. But I started out talking about the idea of life as a self-organizing system, which has to pay the entropy piper in order to avoid its own degeneration, and the OP was talking about the development of rationality / self-awareness / ability to think - which I was equating with the idea of increasing information content in a species' collective minds and bodies.

[Rduke55]

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But the selection of the phenotype isn't chance. that's the big difference.

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The genotype is more important as it is heritable. The phenotype does change in a on-random way in response to environmental conditions so you are correct that its selection is not based strictkly on chance, but that's not the most important point to make here.

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Whoa! You can't say genotype is more important than phenotype. They're both equally important. Selection acts on the phenotype, the genotype is what is passed on.

And the phenotype dosn't change, the frequency of phenotypes change.

[Rduke55]

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There's no room for talk of "improvement" towards the "ultimate" in evolution

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You can use different words if you prefer. A niche is a local maximum of a fitness function. A selection pressure is something which results in the fitter genes being passed on in preference to the less fit, and acts over time to move the species along the gradient of a fitness function. Speciation is possible near saddle points of a fitness function.

Do you find it strange that I use the word "improvement" (relative to whatever measure of fitness) to describe change in response to selection pressure?

I don't know how you can talk about evolution and NOT be talking about progress towards some theoetical optimum.

Some functions in some spaces (including all functions continuous on closed domains) have global maxima, and some others approach easily described singularities. Do you find it strange I want a name for the set of places a system can wind up if it is given infinitely long to optimize? (it doesn't have to be a unique limiting species, and, as I said before, we might never get there even if there is.)

[ QUOTE ]

More "complex" is not necessarily better
And it's not more "complicated" that I'm talking about - I'm talking about different.


[/ QUOTE ]

This is true. But I started out talking about the idea of life as a self-organizing system, which has to pay the entropy piper in order to avoid its own degeneration, and the OP was talking about the development of rationality / self-awareness / ability to think - which I was equating with the idea of increasing information content in a species' collective minds and bodies.

[/ QUOTE ]

I don't even know where to begin with this.
That is a seriously oversimplified view of speciation. What about genetric drift and speciation?

There is no theoretical optimum in evolution. Everything changes. Plus, evolution works with what it already has. We as humans (which some would - erroneously - consider as the peak of the evolutionary process) have a constellation of problems that other animals (including ancestral species) did not have.
If what you say is true, why have more recently evolved species went extinct while more ancient species still abound? Are we better evolved than say, the cockroach? Or bacteria? Or fungus? Based on the "working towards and optimum" theory, we are.
We are not. We all fit in a niche. And evolution, while looked at in the long term of millions, hundreds of millions, or even billions of years, actually can work on a much faster time-scale than that.
Nicehs are constantly appearing, disappearing, and changing. What might be good currently, may not be useful in the near future.

[benkahuna]

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Whoa! You can't say genotype is more important than phenotype. They're both equally important. Selection acts on the phenotype, the genotype is what is passed on.

And the phenotype dosn't change, the frequency of phenotypes change.

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I can and I do. Phenotype can change in the lifetime of an organism. The genotye is unlikely to change by more than a few bp (1X10^9/lifetime*2-3X10^9 bp for humans) in a lifetime. And the phenotype is only passed on through the genotype and only meaningful if expressed in future generations. If you don't understand the phenotypic difference in the same rabbit that has dark fur in one season and light fur in another season, you are missing something important. The frequency of genotypes change and it is what matters. You don't honestly believe any organism has the same phenotype throughout it's lifetime, do you? If you do, you're naive about genetics and gene expression. If you don't, you really have no choice but to concede my point.

Selection acts on phenotypes sure, but it may act on multiple phenotypes (almost certainly does) through the lifetime of an organism. Genotype is the common factor of all possible phenotypes of an organism. Due to the influence of environmental conditions in determining phenotype, I'd say genotype is what matters. Phenotype is merely a medium through which a genotype may establish its fitness within particular environmental conditions. Think about it. Logically, you know it's true.

[Rduke55]

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Whoa! You can't say genotype is more important than phenotype. They're both equally important. Selection acts on the phenotype, the genotype is what is passed on.

And the phenotype dosn't change, the frequency of phenotypes change.

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Phenotype is merely a medium through which a genotype may establish its fitness within particular environmental conditions.

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Think about this statement a little more.

[Rduke55]

Also, what about changes in the genotype that do not have an effect on phenotype? Or are neutral in regards to selection?

I'm not saying phenotype is more important than genotype. I'm saying you cannot say one is more important than another.

[benkahuna]

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Also, what about changes in the genotype that do not have an effect on phenotype? Or are neutral in regards to selection?

I'm not saying phenotype is more important than genotype. I'm saying you cannot say one is more important than another.

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Because the phenotypes of an organism are dynamic through its lifetime, I think you first need to at least call them phenotypes. I don't think you're properly considering regulatory genes or recessive traits. A heterozygous condition of a particular allele may not result in major problems for an organism and may thus be exempt from the influences of a selective pressure. Still, these traits may change the likelihood of producing fertile offspring as two heterozygous parents may have 1/4 of their kids with the homozygous recessive condition and those kids die before sexual maturity.

Certain genes do not have 100 percent penetrance and as long as they're latent, everything is fine. If they become active, it can get messy. Such genes may seriously impair the production of fertile offspring, even if they have no impact on the progenitor.

I don't think a given phenotype is unimportant, but genotype is clearly more important. Genotypes represent everything that is possible (along with mostly the mother's double membrane bound organelles and the initially correct conditions in humans) whereas phenotype is simply the expressed genes and resultant morphology/physiology at the time.

If a genotype has the best selection of possible phenotypes, but only one of which is expressed and has the same phenotype as another organism with a different genotype and a less favorable mix of possible phenotypes the superior genotype breaks the tie in terms of fitness and thus genotype is more important.

[Rduke55]

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Also, what about changes in the genotype that do not have an effect on phenotype? Or are neutral in regards to selection?

I'm not saying phenotype is more important than genotype. I'm saying you cannot say one is more important than another.

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Because the phenotypes of an organism are dynamic through its lifetime, I think you first need to at least call them phenotypes. I don't think you're properly considering regulatory genes or recessive traits. A heterozygous condition of a particular allele may not result in major problems for an organism and may thus be exempt from the influences of a selective pressure. Still, these traits may change the likelihood of producing fertile offspring as two heterozygous parents may have 1/4 of their kids with the homozygous recessive condition and those kids die before sexual maturity.

Certain genes do not have 100 percent penetrance and as long as they're latent, everything is fine. If they become active, it can get messy. Such genes may seriously impair the production of fertile offspring, even if they have no impact on the progenitor.

I don't think a given phenotype is unimportant, but genotype is clearly more important. Genotypes represent everything that is possible (along with mostly the mother's double membrane bound organelles and the initially correct conditions in humans) whereas phenotype is simply the expressed genes and resultant morphology/physiology at the time.

If a genotype has the best selection of possible phenotypes, but only one of which is expressed and has the same phenotype as another organism with a different genotype and a less favorable mix of possible phenotypes the superior genotype breaks the tie in terms of fitness and thus genotype is more important.

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I don't think you're thinking about this on the right level.
They absolutely cannot be separated in importance to evolution. I just don't know why you keep arguing one over the other. Especially using words like "clearly" more important. Whether or not phenotypes change is not the issue.
They are both neccessary and essential for selection.
It seems like you have a grasp of how genes work but I think you're not thinking about the big picture here.

Darwin postulated 3 conditions for natural selection. 1) Variation of traits in a species, 2) Heredity of those traits, 3) Differential reproductive success based on those variations.
The first is genotype expressed as phenotype. The second is mainly genotype. The third one is mainly phenotype.
Take away any of those and the whole process does not exist.
When something is necessary and essential for a process you can't say something else that is also neccessary and essential is more important.

I just don't understand where you're coming from on this.