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Comment by briga | Hacker News Reader

In his book What Technology Wants, Kevin Kelly makes a pretty convincing case that evolution, and by extension technology, is convergent upon certain forms. The eye evolved independently several times in natural history not by coincidence, but because the eye is a universally useful structure that an evolutionary process will eventually stumble upon. The same is true of ideas and the same is probably also true of brains. I wouldn't be surprised if life on other planets had forms similar to life on earth, simply because so many of biological structures on earth are so well optimized towards survival.

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When you think about it, it's not that surprising. Function driven body parts like the eye will evolve to optimize function. Almost by definition there will be one optimal design.

The superficial diversity we see in, say, Birds of Paradise plumage has more freedom to evolve in different ways because there are many more ways for a bird to 'look good' to other members of its species than to design an eye that functions well.

Sorry to be that person, but nothing evolves "for" any one function. And one can't prestate the potential set of functions of any subsystem of an organism. It's the other way around: systems evolve, we ascribe functions to them after the fact.

It's better to say that similar environments, pressures and circumstances result in similarly evolved features.

Are you a nihilist or just parroting? I for one don't even do anything "for" anything.

It's funny how your argument can be applied against determinism and free will at almost the same time.

Actually I believe in free will, and I don't think the universe is deterministic, and I am partially parroting. But evolution has no purpose and nor does the universe. Purpose is something we humans (and possibly other animals) invent for ourselves, i.e. purposes are created by evolution.

But evolution does work via purpose, whereas mutations that aren't fulfilling a purpose will not create an evolutionary advantage. So the antropomorphism is just a sylogysm.

Maybe eg. the dying of species, broadly taken as an evolutionary mechanism, doesn't seem to serve an advantages purpose, although maybe it's just a mutation of (local) state all the same, so maybe or not that's advantageous for the universe.

A purpose implies intent or some kind of forethought, which evolution works completely without.

It's not a positive action (there is light so we need to develop eyes), but a passive result (there is light so the ones who happened to have eyes survived more often and reproduced more successfully).

As a matter of fact, antropomorphisms are a very popular figure of speech and I've never seen much come from a remark against the preoccupation of evolution.

The funny thing is, when you talk about human procreation suddenly there is intent and the goal post could be shifted to exclude those cases where pregnancy was not expected and I could probably question the cases where it's intended too because "a child" is a very broad cincept and as after thought not all cases turn out as expected and I would keep shifting in the same way you were about evolution, just to provoke discussion about free will and where to draw the line.

Maybe frequent reminders against creationisms are necessary to provoke fundamentalists, which I don't personally have contact with, so this meme is just boring.

But aren't there quite a few ways to design a well functioning eye? Compare insect eyes to human eyes to mantis shrimp eyes, and there are some pretty big differences.

A given environment will give a certain kind of pressure and demand a certain kind of solution. Bring the ancestors of mantis shrimps to the treetops and neothlithic apes to the ocean floors and they would both die... If you fix that and let them somehow compete on vision they would likely converge on eyes like the those currently living in the environment have.

Don't insects and monkeys live in overlapping environments with radically different eye structures?

Path dependency. Insect eyes and vertebrate eyes presumably each occupy their own unique minima in the energy landscape. Even if we could describe a cost function that picked one of them as more globally optimal, moving from one to another would be hideously expensive.

It's also possible that compound eyes have an advantage at smaller eye sizes---or maybe a better way to put it: their disadvantage relative to vertebrate eyes is less pronounced for equally small eyes. Pure speculation on my part though.

Or maybe, we tend to categorize eye-like organs as similar and as universally useful structures because that's what we are looking for, doesn't always mean it's really there though.

Whiskers/feelers are another one that comes to mind as evolving several times.

The ratchet is a the simplest universal physical mechanism that seems to fall out of physics into chemistry and biology all the time.

eyes are a bit more subtle. It would be really interesting to know the specific trajectories of evolution that led to the formation of sensitive pigments (probably the earliest vision systems), through the development of lenses, etc.

You can see a fair bit in the Cephalopod order, from the Nautilus (https://en.m.wikipedia.org/wiki/Chambered_nautilus) which has no lens, the Cuttlefish with monochromatic vision through to the Octopus.

It's interesting to observe the differences, cephalopods don't have blind spots and can perceive polarised light.

I'd rather see the actual historical events that happened (like a movie made by a time machine) rather than reconstructions from extant organisms and fossils.

BTW, humans can kinda see polarized light (https://en.wikipedia.org/wiki/Haidinger%27s_brush).

Interestingly, cuttlefish have monochromatic vision but their camouflage matches the color of their surroundings. Presumably, they get the color signal through color-capable receptors in their skin.

Cuttlefish are weirder than that, the current theory is their W-shaped pupil causes chromatic aberration on the retina and they can use that to detect colour.

http://news.berkeley.edu/2016/07/05/weird-pupils-let-octopus...

Wow! I wonder if we could we potentially infer color from black & white photos of celestial objects, by this technique? Maybe it could be combined with the adaptive optics that attempt to cancel stuff like this?

you can already do similar things with filters, you don't need any exotic biology to do it.

But filters block light, reducing the effectiveness of the telescope. Also, you need to set them up before the photos are taken. I am suggesting a way to process existing grayscale photos, where the operator may have decided that filters weren't worth diminishing the captured light, or the increase in communications bandwidth.

Hmm, I'm skeptical. Beyond meaning they'd need to be reclassified as color-vision with a unique mechanism (in itself interesting), it doesn't really address how the camouflage on the top of the squid matches what's below in (where its eyes can't see).

BTW: a press release and Science paper is not "the current theory".

The Blind Watchmaker discusses the physical evolution of the eye. Here's a video:

http://www.dailymotion.com/video/x3lstd5

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