At what order of complexity...

Originally posted by DeepThought
Biology admits teleological explanations. It is different from physics in that respect. The chicken crossed the road to get to the other side.

This does not, however, mean that the purpose of evolution is to create humans. Certainly teleological explanations are not admitted for abiogenesis. But once life has started then cells start behaving with ...[text shortened]... istake is to think that because the higher levels have this property the lower levels must also.

Forgive me if I misunderstood what you're trying to say, but I think I'm slightly in
disagreement with you here, because I don't think that you can say that a bacteria or virus
act with a purpose. I believe that requires some kind of will power, the ability to choose a
path. If all you do is blindly react to the environment you find yourself in, as any brainless
form of life does (and indeed some forms with rudimentary brains), you're really not all that
different from a chemical reacting with other chemicals. On the cellular level, that's really
all that's happening.

Yes, a bacteria has the ability to move around, and is not just waiting to get in contact with
a food source, but it's hardly anything like a dog, sniffing a trail to find its intended target.
On this level of biology, there's no such thing as a thought, let alone a plan.

I agree with you wholeheartedly that evolution is not aiming for a specific goal, such as
producing humans, and that higher lifeforms of course give purpose to their own
existence.

Again, forgive me if I completely misunderstood.

Originally posted by DeepThought
Biology admits teleological explanations. It is different from physics in that respect. The chicken crossed the road to get to the other side.

This does not, however, mean that the purpose of evolution is to create humans. Certainly teleological explanations are not admitted for abiogenesis. But once life has started then cells start behaving with ...[text shortened]... istake is to think that because the higher levels have this property the lower levels must also.

I say that God did the original DNA programming for reprodution in each kind of plant and animal he made. After that God let the programs run.

Originally posted by C Hess
Forgive me if I misunderstood what you're trying to say, but I think I'm slightly in
disagreement with you here, because I don't think that you can say that a bacteria or virus
act with a purpose. I believe that requires some kind of will power, the ability to choose a
path. If all you do is blindly react to the environment you find yourself in, as any ...[text shortened]... ourse give purpose to their own
existence.

Again, forgive me if I completely misunderstood.

Bacteria: The main purpose for plants is to grow and provide suitable environments and food for animals.

Originally posted by C Hess
Forgive me if I misunderstood what you're trying to say, but I think I'm slightly in
disagreement with you here, because I don't think that you can say that a bacteria or virus
act with a purpose. I believe that requires some kind of will power, the ability to choose a
path. If all you do is blindly react to the environment you find yourself in, as any ...[text shortened]... ourse give purpose to their own
existence.

Again, forgive me if I completely misunderstood.

A virus is not independently alive. So no they do not have purpose. With a single celled organism I think it is a rather difficult question. I've got sympathy for your objection. I certainly don't think they are conscious or self-aware. But evolution has given them genomes which react to their environment in a way that looks like purpose.

Certainly when looking at human behaviour we can say something like: "He did it because it suited his ends.", with a protozoan that is a rather dicey statement. Biologists prefer to avoid admitting to teleology. The Wikipedia page on teleology has a nice quote:

J. B. S. Haldane said, "Teleology is like a mistress to a biologist: he cannot live without her but he's unwilling to be seen with her in public.".

When one asks the question "Why did the protozoan exhibit this behaviour?" it is difficult to answer it elegantly in non-teleological language, the answer: "To get food." is just so much snappier than "Receptors on the cell membrane triggered metabolic pathways to activate the flagellum causing the cell to migrate towards a more nutrient rich location.". One could make a similar biologically reductive statement with a human, but stating that humans have ends in mind is not controversial. I think the fact that the response is programmed doesn't prevent it being with a purpose, provided one's definition of "purpose" does not rely on consciousness.

My background is in physics, where teleological arguments are right out. I'm arguing for teleology in biology as an emergent phenomenon. Quite what the level of complexity of an organism needs to be before one can reasonably assign purpose to it is another matter. I don't think protozoans have such a thing as intent, but a purpose one can make an argument for.

Originally posted by DeepThought
A virus is not independently alive. So no they do not have purpose. With a single celled organism I think it is a rather difficult question. I've got sympathy for your objection. I certainly don't think they are conscious or self-aware. But evolution has given them genomes which react to their environment in a way that looks like purpose.

Certain ...[text shortened]... don't think protozoans have such a thing as intent, but a purpose one can make an argument for.

I can see how it's tempting to write, and certainly easier to read: "certain flowers evolved
the ability to produce nectar that bees are attracted to, so that they can cross pollinate with
flowers of the opposite sex, thereby ensuring the continued survival of said plant", implying
some kind of purpose-driven evolution, rather than: "it just so happened that through
incremental steps some species of plants evolved alongside some species of insects, both
adapting through a non-purposeful evolutionary process over a series of generations to
mutually depend on each other, such that current generations now live in symbiosis", but
the latter is nontheless the more accurate, even though the illusion of purpose is clear.

Originally posted by C Hess
I can see how it's tempting to write, and certainly easier to read: "certain flowers evolved
the ability to produce nectar that bees are attracted to, so that they can cross pollinate with
flowers of the opposite sex, thereby ensuring the continued survival of said plant", implying
some kind of purpose-driven evolution, rather than: "it just so happened ...[text shortened]... but
the latter is nontheless the more accurate, even though the illusion of purpose is clear.

Fourth Grade Science

Wherever you find plant life you will also find animal life. They need each other to survive.

http://schools.bcsd.com/fremont/4th_sci_life_plant_animals.htm

YouTube

YouTube

Originally posted by DeepThought
A virus is not independently alive. So no they do not have purpose. With a single celled organism I think it is a rather difficult question. ...... I don't think protozoans have such a thing as intent, but a purpose one can make an argument for.

I don't think you can actually make any argument for a single celled organism that will not work equally well for a virus. Whether or not we classify a virus as 'alive' is irrelevant as is whether or not it can survive independently.
In fact, it has been argued that the unit of teleology, if there is one, is the gene - as in the book title "The Selfish Gene".
However as others have said, it is an illusion in that successful replicators are the ones that survive, so it appears that successful replication is an 'intent' when it isn't. But this terminology is not unique to biology. One for example may say that 'water seeks its own level' or 'a protein seeks its lowest energy configuration'.

Originally posted by C Hess
I can see how it's tempting to write, and certainly easier to read: "certain flowers evolved
the ability to produce nectar that bees are attracted to, so that they can cross pollinate with
flowers of the opposite sex, thereby ensuring the continued survival of said plant", implying
some kind of purpose-driven evolution, rather than: "it just so happened ...[text shortened]... but
the latter is nontheless the more accurate, even though the illusion of purpose is clear.

I see purpose as a reality not an illusion without the evolutionary
process thrown in. Where we differ is you want to make life and all its
complexity through evolutionary change as true as gravity for handling all
the complex system generation in all life. I find it amazing that you can just
gloss over all the various systems in all of the vast array of life and say to
all of them what else would we see, it had to happen!

You could do the same thing with houses, we see walls so thick, the doors
hung just right, the window placed properly, and so on. Building anything
requires time, effort, and a plan, you just write of one possible explanation
to completely buy into the other. One is reality, I agree and the other an
illusion, we just find ourselves disagreeing on which is which.
Kelly

Originally posted by KellyJay
I see purpose as a reality not an illusion without the evolutionary
process thrown in. Where we differ is you want to make life and all its
complexity through evolutionary change as true as gravity for handling all
the complex system generation in all life. I find it amazing that you can just
gloss over all the various systems in all of the vast array o ...[text shortened]... I agree and the other an
illusion, we just find ourselves disagreeing on which is which.
Kelly

To me the theory of evolution is a fairy tale, not an illusion.

Originally posted by RJHinds
To me the theory of evolution is a fairy tale, not an illusion.

I disagree with that, I believe there are changes in life forms over time, but
I do not at all agree that you'd see the major changes required over time
to turn the very first life form that sprang from non-living material to have
it then through ages continue to turn into the vast array of life we see today.
Kelly

Originally posted by RJHinds
Fourth Grade Science

Wherever you find plant life you will also find animal life. They need each other to survive.

Because animal and plant life evolved together through a mindless natural process we call,
you guessed it, evolution, you'll find that a lot of life forms now live in co-dependence, such
that one could not (or is unlikely) to survive without the other.

I guess in a limited sense you could say that because the bee and the flower depend on
each other, they have some kind of purpose to their existence, but that's a purpose in the
dullest, most meaningless sense, surely.

Originally posted by C Hess
Because animal and plant life evolved together through a mindless natural process we call,
you guessed it, evolution, you'll find that a lot of life forms now live in co-dependence, such
that one could not (or is unlikely) to survive without the other.

I guess in a limited sense you could say that because the bee and the flower depend on
each other, ...[text shortened]... rpose to their existence, but that's a purpose in the
dullest, most meaningless sense, surely.

EUKARYOTIC CELLS - A Devastating Blow For the Fairytale of Evolution!

YouTube

Originally posted by twhitehead
I don't think you can actually make any argument for a single celled organism that will not work equally well for a virus. Whether or not we classify a virus as 'alive' is irrelevant as is whether or not it can survive independently.
In fact, it has been argued that the unit of teleology, if there is one, is the gene - as in the book title "The Selfish G ...[text shortened]... e may say that 'water seeks its own level' or 'a protein seeks its lowest energy configuration'.

No, viruses are inert outside of a host cell. There is no protoplasm. Some bacteria can move under their own power, they can react to their environment. So a bacteria can do something in response to its environment towards an end. A virus cannot do it. Once it's in a cell the chemical pathways of the cell determine what happens.

I don't think teleological descriptions are helpful for evolution, but are useful when looking at behaviours.

Originally posted by DeepThought
No, viruses are inert outside of a host cell. There is no protoplasm.

http://en.wikipedia.org/wiki/Viral_entry
Not as simple as you might think.

Once it's in a cell the chemical pathways of the cell determine what happens.
Just as chemical pathways determine how a bacteria moves. Its all just complicated chemistry.

I don't think teleological descriptions are helpful for evolution, but are useful when looking at behaviours.
I think they are very helpful, so long as we don't get confused by it.
But I do realise that I had misunderstood your previous post in that I thought you were talking about evolution in both cases (bacteria and virus).
But even in terms of behaviour and response to environment - even the humble protein shows a significant amount of reaction to its environment - allowing them to regulate chemical pathways with precision.

Originally posted by RJHinds
EUKARYOTIC CELLS - A Devastating Blow For [...] Evolution!

Not really, no.