I always wanted to have this conversation, but I never found “intelligent design" or “irreducible complexity” to be objective arguments. So I decided to loosely give them operational definitions, which aren’t perfect, but get the point across in an objective way.
1. Design – Anything requiring unique intervention to be achieved. For example, an anthill shows design because dirt does not gather into intricate mounds on its own, it requires ants. (Notice this is extremely broad; but contains no subjective notions about what is and isn't good design).
2. Irreducibility – The inability of something to be reduced or have properties removed without losing important functions.
Almost all animals have eyes. Not only that, but the underlying genetics for the development of photoreceptors is shared by everything from vertebrates to arthropods . To evolutionists, this means the genes were present before speciation occurred. Yet we have no info on what the first eyes were. We can only look at the simple, yet updated eyes of modern species. For example, phototropic bacteria exhibits complex behaviors in response to light. Planarians have “simple” eyes spots, but a more complex nervous systems than jellyfish.
Human vision exhibits a high level of design. By that I mean that even with our designed technology, we haven’t fully been able to replicate the entire system. This complexity means that all mechanisms have to work together, in perfect balance, for the entire process to work correctly. Aka, its irreducible.
Start with the extraocular muscles. We need them to not only move the eyes, but move in unison. Strabismus occurs when these muscles are not aligned, and it comes at the cost of depth perception. These types of misalignments can lead to amblyopia, in which signals from one eye are turned off. You also need your iris and ciliary muscles that adjust the lens to work right. Tear ducts, eyelids, eyelashes and eye brows all play important roles.
Your eyes also need to communicate with the vestibular system. Try to film with a camera while running, all you’ll see is a blur of shaky images. But you don’t have that problem with your eyes because we have a VOR reflex. It means information from our vestibular system travels through our brain and into the extraocular muscle to stabilize the image. Automatic and voluntary systems then work in unison to give us a steady image. If you have eyes but no vestibular system, your vision is useless.
The overall shape of your eye has to be perfectly balanced. Light has a narrow range at which it can focus on the retina. If your optic axis is too short or too long, you’ll have myopia or hyperopia, and be unable to see clearly. Your cornea also has to have a specific shape, any irregularities and you’ll end up with astigmatism. Your lens needs to be elastic enough, otherwise you’ll be unable to focus light, and have presbyopia. If the pressure within the fluid-filled chambers is too high, you'll have glaucoma and may damage your retina.
It goes without saying that photoreceptors are important. Diseases like macular degeneration and retinitis pigmentosa, in which photoreceptors slowly degrade over the lifespan show their irreducibility. Monochromacy occurs when a person lacks either rods or cones. In each case there are clear deficits. If the person lacks cones, then not only will the world appear black and white, but they will be unable to see during the brightness of day.
I could go on, because the real magic occurs not in the eyes, but in the brain. Not only that, but vision is important for many, many, many behaviours. From sleep, to eating, to falling in love. I'll save these for the comments.
So, seeing how the medical literature is extensive and clear about how much can go wrong if even the slightest thing is off, how exactly did it evolve via small random increments? Even the extremely rare mutations that give some women tetrachromacy (four cones) don't matter much because the brain isn't built for four cone types.
Vision isn't a single thing, its many things working together. That's true of even phototropic bacteria.
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It is a fascinating subject indeed, I think the fact that most creationist now dismiss irreducibility, there is really not much point discussing it at length which leaves design.
Is the eye perfectly designed? One could easily argue no! Firstly take the basic flaws with the eye starting with short sightedness (myopia) this iss a huge defect that is not caused by injury or overuse but is just simply too long.
Images focus sharply before they reach the back of the eye and then fall out of focus again as they finally land on the retina. It’s just down to bad design.
On the flip side you have the opposite problem, far sightedness!
There two forms of this with one being hyperopia, these eyes are built too short and the light fails to focus before hitting the retina, giving yet another example of poor construction.
Presbyopia is the other form of this and is mostly found in older people, where progressive loss of the flexibility of the lens and/or failure of the ciliary muscles to pull on the lens and focus light properly.
You could also chuck in problems such as glaucoma, cataracts, and retinal detachment.
It's a known fact too that most people suffer visual deteriation before pubity or teenage years and I can testify to this, I have been a glasses wearer since I was roughly 13 haha!
Now if we compare this to say birds of prey?! It's hardly a contest! Most birds can also see different wave lengths and ultra violet light.
Also they can with their own eyes detect north and south poles whilst migrating...
One could wonder if they are aware of that fact though? Food for thought...
But let's consider other facts...
-Cats have far better night vision then humans
-Most animals see better in dim light then us
-A lot of birds have translucent eyelids that allows to directly look at the sun without retna damage
-Most birds can see way further then humans
-The cats eye can detect a single photon of light in the dark
So whilst we all agree its amazing, it's piss poor comparatively to other creatures.
I think this leaves it clear that evolution is the source, but there are plenty of brilliant documentaries regarding this and a wealth of literature from experts in the field.
But thank you John for a wonderful topic that was well written with genuine points, this is a huge interest to me and a personal hobby I've studied for a long time! I would recommend Dawkins but I know he's not popular with theists Haha!
The problem is that "perfection / good / bad" are subjective terms, which I tried to avoid in my definition. To argue that something is badly designed, is to argue that it was designed nonetheless. It doesn't solve the problem you think you're solving.
I mentioned myopia and hyperopia in my OP. They are disorders of accommodation. Disorders are a disruption of normal function, meaning they are not designed to function that way. Referring to them as bad designs is a non sequitur. In contrast, many disorders of vision are the result of mutations, and mutations are the method by which evolution is supposed to have produced the eye. It makes no sense.
That said, I prefer using the term different as opposed to better when comparing things across species. I could list all the ways in which the human eye is better than the animals you mentioned, but what's the point? We all use our eyes for different purposes.
I'm glad you enjoy the topic btw lol.
Well let's not get caught up in semantics or linguistic masturbation lol, You know what I mean, I'm near here to have a debate on logic with you, that is pointless... I just like to talk about what is scientifically proven.
In fact I hate to even say 'design' because we know what baggage that comes with...
You could argue both sides, yes it is considered a disorder of course, but you must also accept that is due to the optical power of the eye itself! It is too strong for the corrisponding axiel length.
If the eye was perfectly designed by a perfect agent, surely this would never happen.
I would happily concede and admit that it is a wonderfully complex system.
Not strictly correct there my friend, mutations specifically relate to natural selection if we are being specific... it is the survival and reproduction of individuals due to phenotypes!
It is an integral part of evolution however and is the reason for heritable traits of populations over time.
Variation is within every population or every single organism known to man, and this happens because of random mutations in the genome but these genomes interact at all times with their environments and this again causes variation in traits.
If you think about this, it perfectly explains the disorders and conditions that occur with eyes!
Would you not concede that is more likely and rational than an infinitely powerful and perfect agent that seems to not be able to make anything perfect? Just a thought by the way...
Hmm right, so shouldn't survival and reproduction be affected when you have myopia? You can't see your mate, and you can't see the predator, so you die and don't reproduce.
If we take the balanced retina on a focal point of light to be our endpoint. Then whatever came before must have been either slightly shorter or slightly longer, which in either case causes blurry vision.
In other words, unless your claim is that the retina mutated into perfect balance in a single step, then there has to be a long succession of blurry-eyed species that were still capable of reproducing, and still survived, before it reached a balance at the focal point.
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Yes of course, but reproducing was not in the correct context.
It's a mutation caused by SLIT and NTRK-like protein 6 which s a protein that in humans is encoded by the SLITRK6 gene and are integral membrane proteins.
Which is why myopia is considered hereditary like colour blindness. It's not a guarantee like any hereditary traits, but does increase the likely good of certain outcomes.
well done, many confuse evolution and random selection.
your description of it was correct to.
Thanks very much.
I recommend you to watch this video in which Neil deGrasse Tyson in the magnificent series Cosmos, explains, in a very beautiful way, how the eyes evolved by the process of natural selection. It's a 5 min. video, and it's worth watching it.
https://www.youtube.com/watch?v=4SXHMm5I-68 Neil deGrasseTyson explains how the eye evolved.
Also, if you want further explanation, here's a couple of other links to Dawkins' videos.
https://www.youtube.com/watch?v=2X1iwLqM2t0. (a science tv show)
https://www.youtube.com/watch?v=fzERmg4PU3c (a christian tv show).
I hope this solves your doubts.
P.S. In case anyone is too lazy to watch it: the answer is that the eye was the result of mutations of the first bacterias on Earth, that the process went on and on, improving and improving over millions of years.
Far more poetic and and far more amazing that any "intelligent design theory". And the best part is that this is not something that people from the Bronze Age, with no scientific knowledge guessed, this is the result of real investigation and tested facts.
Cosmos is awesome. I own both Sagan's and Tyson's edition on DVD lol.
That said, the clip is simplifying things a lot. Which is great for explaining things, but not so great for understanding things. There's two problems here:
1. Mutating a light-sensitive protein doesn't do anything unless that protein has a method of communicating that information and the specimen has a way of responding to that information. For example, the majority of these bacteria use light as an energy source. That means that unlike what the video showed, these bacteria want to move towards brighter light not away from it.
In order to do this, these bacteria already have flagellum. The bacteria go through a 'run' and 'tumble' sequence. In which they rotate the flagellum one way, to move in a straight line, then rotate it the other way to tumble and change to a random direction. There's no thinking involved here. They simple alternate between run and tumble sessions, but in the presence of light, a crazy chemical cascade occurs that makes them run a little longer than they tumble. By this method they slowly but imprecisely move towards light. Things need to be in place before a light-sensitive protein causes any useful behaviors.
2. The jump from phototropic bacteria to planarians (flatworms) is not a simple one. Planarians have a nervous system now, they have muscles, and they are multicellular. Its a completely different world, so its not a simple evolutionary jump. Not only that, but as I mention earlier, phototropic bacteria use light as an energy source. I don't know any multicellular organism (none that matter) besides plants that uses light as an energy source.
If anything we evolved from chemotrophic bacteria, which use their flagellum to chase after certain chemicals, not after light. So that's a problem. Another problem is the behavioral change, bacteria use "vision" to move towards light for energy, but planarians use vision to run away from light.
Ufff, very difficult for me. I've found this study conducted by two scientists from the University of Berkley in 1992. Maybe you can find the answer... http://redwood.berkeley.edu/vs265/landfernald92.pdf
I disagree. Animals and insects that live permanently in caves are totally blind even though it is clear that they have eyes that at one point in their evolution functioned perfectly. So eyes evolved and regressed by evolution and need.
I don't think that the genes were pre-programmed to develop eyes. I think that simpler species developed a need for rudimentary vision and evolve sight and various versions of it. Your skin sense heat which from the most part comes from a light source. Early species needed light to process their food source. The individuals that could sense or reach that source survived better. Thus eyes developed.
Scientists have developed eyes in flat worms that have no eyes. They used genes from other animals and implanted them into the worms. They were not stem cells or eye cells. They were skin cells.
Interestingly, I don't have a problem with things regressing, losing their function, or becoming vestigial. Perhaps it is still evolution, but its a destructive evolution, not a constructive one. Since I consider most mutations to be destruction, I can definitely see things losing function over time.
That said, any manipulation a scientist does crosses the line from the blind forces of evolution into intelligent design. The intelligent designer being the scientist in this case.
May I offer you some peer reviewed evidence - http://faculty.jsd.claremont.edu/dmcfarlane/bio145mcfarlane/PDFs/Nilsson...
This is the paper, 'Pessimistic Estimate of the Time Required for an Eye to Evolve' by Dan E. Nilsson and Susanne Pelger
I didn't see Lucy's comment... well, review both papers in that case XD
Two for the price of one! lol
@Orignal post
While technically true, we would not want to anyways, except to perhaps restore vision to someone that lost their eyesight and do not want the human brain to re-learn how to "see." We have for quite a while, had camera lenses that, for their specified use are far superior to the human eye. And as you say later, a lot of the "miracle" of human eyes is the brain that can process the signals from the eye.
Yep to work for our eyes as we need them. Evolution gave us opposable thumbs and eyes that do well with fine detail, giving us the ability to manipulate objects well, allowing us to use tools. There is a reason why cats/dogs quickly get bored of most TV unless their is an animal like object flitting around a mostly static screen, their eyes are designed to see motion/movement not see fine detail. But that dog will "see" the squirrel in the tree long before your eyes will notice it even though a dog's eyes is not their primary sense organ.
Via billions of reproduction cycles, where every variation is tried, and the ones that reproduce more often gets carried on to become dominate, where the variations that reduced the odds of reproduction would fade out. Billions upon billions of chances to get the eye "right" enough for our use seems very possible to me.
I think we're entering an age where we do want to replicate the entire system. When it comes to AI or self-driving cars, we don't just want the right cameras, but a car that can process that visual information, and make decisions and judgements on it.
Interestingly enough, we used to have self-driving cars once that were great at this. They're called horses.
Our technology is playing catch-up with biology.
I like your bit about horses. They could always be counted to take you back home from the bar, no matter how drunk you were for the most part. As long as you treated your horse nicely anyways and you could make the climb up the saddle. Never had to take your horse in for "repairs" either. Horse shoes were not required until we started making roads, and those saddles they made back then were tough.
To bad they are so much more uncomfortable than cars and so much slower :)
The self driving technology is already here for self driving cars, we just lack the will/political will to see it through. So we have to do it the hard way, and piece meal it in. (we are trying to replace the human driver, instead of the transportation system.)
I doubt the overall shape of your eyes is perfect; and I can tell you without a doubt, mine are not.
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Photo-receptors have evolved independently, more than once.
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What are the dimensions of design? What is a unit of design? How much of this unit does "human vision" have?
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What are the dimensions of complexity? What is a unit of complexity? How much of this unit does "human vision" have?
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Again, my eyes work pretty good, but they are certainly not perfect.
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Having a vision system that only works when you are stationary is NOT useless.
Most of these objections address subjective problems. I mentioned in my OP that I tried my best to eliminate them. So if you have a better method, or have dimensions for design and complexity. I'll gladly adjust my OP accordingly.
To your last point. Correct, but how many species with eyes remain stationary? Those that are stationary, like plants, don't need vision. At most plants turn their leaves in the sun's direction, which could be a step towards vision, but not vision.
Yes, your use of the words "design" and "complexity" appear subjective. Which allows you to make any claim you want about them, and we can't possibly verify or falsify those claims; because I'm guessing they mean what you need them to mean, when you need them to mean that. Perhaps you shouldn't use such quantities if you are trying to avoid subjectivity.
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For what it is worth:
Complexity is typically dimensionless. It is often expressed in Big O notation; but it is not obvious how to relate what you are saying to that. Also complexity (as it is often used) increases spontaneously; so the notion that something with a large amount of complexity can't come from a random process is fundamentally misguided. Again, this probably stems from you using the word in a very different way, which is why I asked you the questions about it.
Design is a non-sense quantity as far as I can tell.
Well its not a non-sense quality, because we know plenty of examples of it which are sensible: Cars are designed, planes are designed, even this website is designed. The problem isn't with the word since we all know what it means, and atheists have no problems arguing for bad designs. The problem is how do we apply it.
Complexity seems quantifiable though. I would argue its a measure of its components. Communication between two neurons is a simple nervous system. But one with billions of connections and dynamics is a complex nervous system.
P.S. I'm not sure what complexity you are referring to that increases spontaneously, But my argument isn't that simple things can't accumulate to become complex. Rather, its that complexity often has emergent properties that can't be reduced to simpler things.
Perhaps so, but:
You introduced it as presumably a binary property:
Then started presumably used it with magnitude:
This is why I asked you for its dimensions. Since it seems you can't provide that information; I have to conclude it is subjective, and subject to your whims, making it meaningless to the rest of us.
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Of course you don't, because you aren't using it the way it is used in the sciences. Having talked with you several times I realized this immediately and instead of criticizing you for it, I asked you to define it; which you seem unable/unwilling to do. Which leaves us with the situation where it can mean exactly what you need it to mean at any moment; which makes it meaningless to the rest of us.
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I don't know what you mean by it, I only have a vague notion. Which again lets you claim it means whatever you need it to mean, whenever you need it. You aren't going to convince anyone who doesn't already believe you with that.
What is the complexity of a 1 kg rock? If you need more details, feel free to make them up but please list them.
"Of course you don't, because you aren't using it the way it is used in the sciences." -Nyar
Funny, my science textbooks seem to have no problem using the word complex. See attachment.
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"I don't know what you mean by it, I only have a vague notion" -Nyar
Forgive me, but I'm afraid I too only have a vague notion of what the words 'rock' and 'more details' mean. I'll gladly provide an answer. But seeing how rocks come in many shapes, sizes and materials, even after you account for mass. It leaves me with the situation where it can mean exactly what you need it to mean at any moment; which makes it meaningless to me.
What are the dimensions of a detail? How do I know when I've given more?
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Clearly it is dimensionless. It is one piece of information about something. I know what you are doing. But I was being serious when I said that. I have NO IDEA how to tell if a rock is more designed than a sports car. I have a visceral notion that the car is more designed, but when it comes down to the brass tacks I don't know how to measure it. When someone starts making magnitude arguments about something that can't be measured; reach for your wallet.
I really could care less what your stamp collecting text book says. If it uses complexity in that way, it is pulling a fast one also (but from that snippet it looks like it might be using it as a binary property).
edited to fix several grammar mistakes
Rock vs Sports Car.. I see.
Sometimes I can't tell if I'm supposed to use a tree bark or a toothbrush to brush my teeth. I have a visceral notion of which is more designed for brushing teeth, but... truth be told since I can't measure it, I just don't bother using either.
Funny, but that is kind of the point. It reminds me of a quote from Rutherford: "That which is not measurable is not science."
Which also reminds me of a funny story that happened my first day in a real science class (not a stamp collecting class). The instructor asked a question and the obvious answer was "mass". I decided to show off and blurt it out. He then asked me how to measure mass. I tried to give a few examples but he quickly showed that they were not in fact examples of how to measure mass. When it was obvious I didn't know how to measure mass he said something more or less along the lines of "don't make statements about quantities you don't know how to measure." I'm hoping you can learn from this experience, without having to suffer the embarrassment I had to.
The eye evolved over a long period of time. This still doesn't prove a god designed it that way.
How evolutionists sound when explaining how long things take to evolve lol: https://www.youtube.com/watch?v=u_aLESDql1U
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