Vision and Evolution (A Critique of Dawkins)

[The Grand Nudger]

A good example of hypothetical structures and relationships.

A photo receptive cell sending a sing along to a cluster of motor cells all on the top of a creature.

This would give powerful downward thrust in liquid when a shadow presented overhead. We would interpret this as behavior.

The same system, with analogous structures but in a terrestrial environment - can disperse chemical toxins and repellents towards a shadow as a spray.

More photosensitive cells and more fine control between clusters of motor sells confers vector based detection and evasion, or targeted spraying of voc’s. Fine control requires connectivity.

[John 6IX Breezy]

The issue with sensory organs is that they are there to inform or guide behavior. Given that perception is a highly interpretive process, possessing "half an eye" as you call it, will most likely lead to behaviors that are disadvantageous. Now its worth mentioning that I consider something to be "half an eye" when it is compared to the rest of that organisms structures, not when compared across organisms. So I wouldn't label phototaxic bacteria as having "half an eye" because they come equipped to adequately transform that information into movement. There is a balance of structure there, despite its minimal composition.

Soo you are saying that having bad vision is worse than beeing blind?

In a lot of situations, yes. Take for example a condition that often results from strokes in which the person is unable to see the left half of their visual field. By unable to see I don't mean there is a blackness in that half of their visual field, I mean that it is absent from consciousness entirely, as if leftness didn't exist. This leads to odd behaviors, from not eating the left half of a plate of food to wearing clothes on only half their body. They are guiding their behavior according to a misinformed perception of the environment. This misperception will almost certainly lead to detrimental behaviors that a blind person would not need to worry about.

When it comes to behavior and perception. My position is that no sensory information is better that misleading sensory information. It is better for you to not see the knife on the table, than to see it as an edible fruit.

[notimportant1234]

Soo you are saying that having bad vision is worse than beeing blind?

In a lot of situations, yes. Take for example a condition that often results from strokes in which the person is unable to see the left half of their visual field. By unable to see I don't mean there is a blackness in that half of their visual field, I mean that it is absent from consciousness entirely, as if leftness didn't exist. This leads to odd behaviors, from not eating the left half of a plate of food to wearing clothes on only half their body. They are guiding their behavior according to a misinformed perception of the environment. This misperception will almost certainly lead to detrimental behaviors that a blind person would not need to worry about.

When it comes to behavior and perception. My position is that no sensory information is better that misleading sensory information. It is better for you to not see the knife on the table, than to see it as an edible fruit.

It is not misleading, it is imperfect sensory information. And BTW, eating "Half a plate" is better than not eating at all when you are in the jungle. Your comparation is not in point at all. 
And also you need to know that evolution is not about perfection, it is about fucking and eating( simply put).

[John 6IX Breezy]

In a lot of situations, yes. Take for example a condition that often results from strokes in which the person is unable to see the left half of their visual field. By unable to see I don't mean there is a blackness in that half of their visual field, I mean that it is absent from consciousness entirely, as if leftness didn't exist. This leads to odd behaviors, from not eating the left half of a plate of food to wearing clothes on only half their body. They are guiding their behavior according to a misinformed perception of the environment. This misperception will almost certainly lead to detrimental behaviors that a blind person would not need to worry about.

When it comes to behavior and perception. My position is that no sensory information is better that misleading sensory information. It is better for you to not see the knife on the table, than to see it as an edible fruit.

It is not misleading, it is imperfect sensory information. And BTW, eating "Half a plate" is better than not eating at all when you are in the jungle. Your comparation is not in point at all. 
And also you need to know that evolution is not about perfection, it is about fucking and eating( simply put).

I'm positive most blind people can, and often do, eat an entire plate of food; surely that is better than eating half a plate.

Misleading is the appropriate term, not imperfect. Given that behavior is "lead" by perception, a wrongly processed sensation is able to mislead behavior. Seeing imperfectly is not the same as seeing wrongly.

[The Grand Nudger]

Conveniently, evolutionary theory predicts that organisms with reliable sensory systems will dominate the gene pool. While a wide range of imperfect and inaccurate perceptions are possible, and present in living creatures. The knives for edible fruit misperception isn’t going to be well represented.

This relationship can be reversed for knives as edible fruit as a predation strategy. Of exploiting some misperception in prey species.

If we imagine “half an eye” means seeing fruit instead of knives that would be an issue, but that simply isn’t what “half an eye” is for the extant population, and it’s the genes of the extant population that matter.

---

Now for the fun stuff. From an explicitly evolutionary viewpoint, knives as fruit can be advantageous, if, for example....something about the breeding behavior necessarily involved knives. Seeing s knife would compel the organism to seek out food where breeding was occurring. They found the right thing for the wrong reasons...but, still, there they are, breeding.

It seems convoluted with knives as the unlikely example, but this is the basic value of pleasure in sex, as well.

[John 6IX Breezy]

A good example of hypothetical structures and relationships.

A photo receptive cell sending a sing along to a cluster of motor cells all on the top of a creature.

This would give powerful downward thrust in liquid when a shadow presented overhead.  We would interpret this as behavior.

The same system, with analogous structures but in a terrestrial environment - can disperse chemical toxins and repellents towards a shadow as a spray.

More photosensitive cells and more fine control between clusters of motor sells confers vector based detection and evasion, or targeted spraying of voc’s.  Fine control requires connectivity.

Right, so it seems you agree with the OP that sensation, perception, and behavior evolved simultaneously; or at the very least in a very close back-and-forth relationship. It wouldn't be the case that the eye evolves ahead of the other two, correct? (I'm replying to your two latest comments simultaneously btw).

My issue with even a close reciprocal evolution of all the components, is that once one of the structure gets even a little a head or behind the others, it becomes isolated. The rest of the structure will need to play "catch up" and I'm not sure how they can. To give a possibly incorrect analogy, lets assume eyes evolved from rods to cones in a single step. If cones evolve before the brain is able to process and perceive that new information as color, they become sort of vestigial. Without a brain to process the color information, the organism is unable to guide behavior accordingly, and cones become isolated from selective pressures as well (at least those stemming from behavior).

In other words, a better eye without a better brain seems useless and expensive. So it seems to me that a simultaneous all-or-nothing evolution across the components is the only way to have positive progress. A delayed system runs into too many issues.

[The Grand Nudger]

assuming anything happened in a single step is the easiest way to get the entirety of evolutionary theory wrong.

The same is true of assuming all-or-nothing development.

To use the same example again, we might posit that the structure evolved for moving in liquid water is expensive outside of water, but a VOC pump says otherwise. None of the structures evolved simultaneously, in a single step, or as an all or nothing gambit.

They didn’t even arise from the same evolutionary pathways.

That delayed systems run into issues is made thoroughly apparent in the piles of bones beneath our feet. We’re what remains of those delayed systems.

[John 6IX Breezy]

assuming anything happened in a single step is the easiest way to get the entirety of evolutionary theory wrong.

The same is true of assuming all-or-nothing development.

Right, that's one of the struggles I have with evolution. It flattens staircases into gradual inclines.

As to your knife response above, the issue here would be that I see the "half an eye" analogy as a necessary step towards a "whole eye." In other words, perceiving knives as an edible fruit would be a necessary step on the path of progression, before the necessary hardware evolves to that can perceive knives as inedible. When you say those organisms won't be well represented, that to me is a hurdle that the entire species needs to jump over to keep going. But it seems as if you see it as a side issue that only some members of a species will have, while the rest are able to get around it.

So it seems to me, if I can use an analogy to represent our different ideas, that you view evolution kind of like a bridge. Organisms can get to their destination as long as they travel on the path laid out by the bridge, and those that fall don't. Whereas I see evolution more like stepping stones on a river, organisms can fall to the sides like a bridge, but they also need to jump to the next evolutionary step if they are to move forward at all. Jump too short an they end up in the river.

[The Grand Nudger]

What will become an eye, as you know it, doesn’t need to be an eye at all, as you know it. It doesn’t need to be an eye as you know it or the same thing it previously was at any step to be useful.

There is no destination in evolutionary theory, only a journey.

[John 6IX Breezy]

What will become an eye, as you know it, doesn’t need to be an eye at all, as you know it.  It doesn’t need to be an eye as you know it or the same thing it previously was at any step to be useful.

There is no destination in evolutionary theory, only a journey.

I disagree there is no destination, specially if we're dealing with natural phenomena. In the same way electrons will rest at the lowest energy state; or water traveling down the path of least resistance will be gathered in puddle at the bottom. I have to assume organisms are also trickling down towards a similar state of rest. Its homeostasis, its balance, its gas particles evening themselves out in a container.

Evolution has a destination, and a limited number of paths it can get there (too limited in my opinion)