cool book

We have no idea how well the vertebrate (or any other) eye is designed, only that it seems sufficient for its owner. The same may be said of most of the genome - we have no idea what most of it does, or why.

I have the feeling that we have collectively achieved limit cycle, with the same few points being repeated ever more loudly, with frustration often morphing into ad hominem, and so it would best to just stop.

Joe Gwinn

That's not all what Gurney's paper says. But don't waste your time reading it.

I mean the direction that natural selection moves when out of equilibrium, what happens after a mutation or a change in environment. Presumably mutations that are beneficial to survival will increase in frequency among reproducing hosts better than bad ones.

If a non-inverted retina is optimal, the steps towards an inverted retina (say, blood vessels moving up from the back of the eyeball and scattering light) are bad for resolution so will be deselected. They weren't.

How did we get to the bad local optima? Why don't we evolve away from it? If topside blood vessels scatter light, and the central foveal area has none, why doesn't that area evolve to become bigger? There are no brick walls to prevent that.

Maybe that diameter is optimized.

One more time: we got there by being born that way. Some ancestor was very similar, and that happened by some millions of minor deviations on what was inherited from his ancestors.

Questions like 'why' cannot be identified with any simple fact or set of facts, because when you roll a die, the result is RANDOM. There is no reason why it was a three.

Questions like 'why don't we evolve' are odd; of course, our OFFSPRING might evolve, we'll do other things.

Questions like 'why doesn't that area evolve' are nonsense, since only a succession of different individuals can be said to evolve.

Mothers are very tolerant; ask 'why' and you'll always get an answer. That's the source of old wives' tales.

I'm not your mother.

"© 1999 by Answers in Genesis"

True. However they gain /great/ kudos when they eventually demonstrate the error.

True. Of course that is the "solution" traditionally employed by those that believe in one or other "revealed truth". The Catholic church was infamous for it.

She couldn't have answered the question either.

Darwinian evolution doesn't depend on anything in the process "knowing" anything. The only information available is "all our ancestors survived" and that's it.

Sadly, you don't know what the word "evolution" - or the phrase "Darwinian evolution by inheritance with variation and selection between the variants" really means, and keep on hand-waving about ways it could have done better if there had been an intelligent designer embedded in the process (and mechanisms for giving that designer lots of information which wasn't available until we invented fairly advanced biology).

Because they confirm your existing irrational prejudices?

The argument is not that the eye is badly designed, but rather that if blood vessels and nerves were behind the light sensing cells, it would work better.

Nobody has ever suggested that the eye was "designed" - outside of the creation science and intelligent design lunatic fringe. It evolved.

As well as it can be when the blood supply and the nerve cells are between the light sensing cells and the light source being sensed.

The idea that the eye was ever designed. Gurney spent six years a medical missionary, and he may be emotionally committed to the idea that God could adjust the evolutionary process if he wanted to.

I CBA to debunk Creationist ID crap like that. It is a disgrace that a US university is hosting such gobbledegook masquerading as "science".

Answers in Genesis. Really? Is that how low you have sunk?

Sounds like just another dog with a really superbly desirable stinky stick.

Must have it!

RL

You are not interested in the optics or the signal processing of the vertebrate eye, or how it might have evolved. I'm sure you didn't read the article, especially the part about the heat sink and foveola.

You are all emotion, and not very nice emotion at that.

Even if you don't agree with him (and he mostly asks questions) he is brilliant and often laugh-out-loud hilarious. He's a superb writer. Read it as fiction if you prefer. Actually, he has written fiction. And books about calculus.

I just got an autographed hardcopy first edition of "Less than meets the eye" for $6. I suppose he's not hugely in demand.

But if the initial light sensing patch had the blood vessel in front of the light sensors, it wouldn't have made any difference at all. You've got to evolve an eyeball and a lens to go in front of the retina before the proto-eye starts doing enough for the problems created by having the blood vessels and the nerves in front of the light sensors to start affecting survival and reproduction.

This doesn't mean whatever you seem to want it to mean. By the time the design imperfection could start to matter, moving the blood vessels and the nerve to the other side of the light sensing cells wasn't an option.

That particular style of construction had been built into the eyeball long before the eyeball was doing enough for it's performance to matter

How would we have evolved away from it? A light sensing organ with the nerves and blood supply going up and down through the light sensing cells would have been worse than either other option, and that is the state the eye would have to get into before it could start selecting an option where more of the blood vessels and nerves were behind the light sensing cells.

But the blood vessels are there to feed the light-sensing cells. If the nutrients (and oxygen) have too far to diffuse to get to the centre of central foveal area, the cells right in the middle will be starved. Not exactly a brick wall, but close enough.

Probably.

Nothing crazy about it at all.

Neither are you.

I did. It didn't address the central point.

John Larkin is all vanity, and gets unpleasantly snarky when he gets caught being a twit.

If you are stuck with churning out propaganda, you do have to make it attractive to the reader. If John Larkin likes it a lot, it probably flatters the reader outrageously.

So he's a writer for hire. How come you haven't read his book denying the the existences of anthropogenic global warming?

The link is to a review of a video, so Berlinski may not have gotten around to actually writing the book yet, but one has to expect that it is in the works.

One can guess why.

Neither are you!

You are only interested in believing 6 impossible things before breakfast so that you can avoid thinking about the conflict between testable facts and (your) revealed religion.

You are all faith, and not very nice faith at that.

There's hope for humanity :)