Rumraket wrote:
The mechanism of inheritance IS the issue, because it is the basis of mutation, of heritable change.

Darwin already knew there was a mechanism of inheritance even if he didn't know about DNA. So, it is not the issue here at all.

That IS how a nerve cell becomes senstitive to light. Cells are made of fats, proteins and carbohydrates. These can be changed by mutating the proteins and enzymes that make them. If a cell has proteins that aren't sensitive to light, then mutation is the mechanism by which you make those proteins sensitive to light.

Darwin evidently did not think that his principle of variation (i.e mutation) and selection was sufficient to explain the origins of light-sensitive cells. Else, why would he have compared it o the problem of the origin of life?

BooBoo wrote:

Rumraket wrote:
The mechanism of inheritance IS the issue, because it is the basis of mutation, of heritable change.

Darwin already knew there was a mechanism of inheritance even if he didn't know about DNA. So, it is not the issue here at all.

Of course it is the issue, I just explained why. You've not said anything to contradict my explanation, you've merely reiterated Darwin's confusion.

It doesn't matter that Darwin knew there was a mechanism of inheritance when he didn't know how it actually worked.

We now understand that Darwin had a bad reason for thinking how nerve cells became sensitive to light was of no more concern to evolution that the origin of life. We now understand that how nerve cells become sensitive to light is an intrinsic part of modern evolutionary theory.

BooBoo wrote:

Rumraket wrote:That IS how a nerve cell becomes senstitive to light. Cells are made of fats, proteins and carbohydrates. These can be changed by mutating the proteins and enzymes that make them. If a cell has proteins that aren't sensitive to light, then mutation is the mechanism by which you make those proteins sensitive to light.

Darwin evidently did not think that his principle of variation (i.e mutation) and selection was sufficient to explain the origins of light-sensitive cells.

That's because his principle of variation wasn't what we understand it to be today.

BooBoo wrote:Else, why would he have compared it o the problem of the origin of life?

Because he didn't know any better.

Do I have to repeat myself? We now understand how a cell becomes sensitive to light. It's because of mutations. What is escaping your comprehension here?

BooBoo wrote:I am making no such claim. I am merely saying that Darwin compared the problem of the origin of the photoreceptor cell to the origin of life itself.

Yes he did, so what? Is that important for anything now?

BooBoo wrote:

Thomas Eshuis wrote:He did not consider it a problem for evolution BooBoo.

He did not consider it related to evolution but rather to origination.

And he was wrong, we now understand it's the other way around.

Rumraket wrote:
Of course it is the issue, I just explained why. You've not said anything to contradict my explanation, you've merely reiterated Darwin's confusion.

The existence of a means of inheritance is definitely not the issue at hand.

It doesn't matter that Darwin knew there was a mechanism of inheritance when he didn't know how it actually worked.

Darwin knew that heritable change was possible regardless of its precise nature. That's the essence of evolution.

We now understand that Darwin had a bad reason for thinking how nerve cells became sensitive to light was of no more concern to evolution that the origin of life. We now understand that how nerve cells become sensitive to light is an intrinsic part of modern evolutionary theory.

Maybe. But Darwin did not think his mutation-selection mechanism could account for it.

That's because his principle of variation wasn't what we understand it to be today.

He believed in successive slight modification, which is how you believe a nerve cell becomes light-sensitive.

Do I have to repeat myself? We now understand how a cell becomes sensitive to light. It's because of mutations. What is escaping your comprehension here?

And Darwin knew of mutations (variations). What part of that don't you understand?

Booboo, what is your problem with the second half of the sentence you quotemined?

KeenIdiot wrote:Booboo, what is your problem with the second half of the sentence you quotemined?

How a nerve comes to be sensitive to light, hardly concerns us more than how life itself first originated; but I may remark that several facts make me suspect that any sensitive nerve may be rendered sensitive to light, and likewise to those coarser vibrations of the air which produce sound.

I just am amused as to why Darwin considered the first hurdle to be overcome in the evolution of the eye to be a problem akin to how life first began. I have no idea what "facts" Darwin alludes to that could render a cell sensitive to light or sound.

You could try reading the rest of the book. He lays out his reasons in the chapter.
The eye was a popular example of a clearly designed organ, and was and still is the focus of deniers of evolutionary theory.

BooBoo wrote:

Rumraket wrote:
Of course it is the issue, I just explained why. You've not said anything to contradict my explanation, you've merely reiterated Darwin's confusion.

The existence of a means of inheritance is definitely not the issue at hand.

No, not merely the existence of a means of inheritance, but the specific nature of the mechanism of inheritance.

That's what Darwin didn't know about, and why he didn't think the question was of concern to the process of evolution.

That's why Darwin was wrong about that particular question.

It doesn't matter that Darwin knew there was a mechanism of inheritance when he didn't know how it actually worked.

BooBoo wrote:Darwin knew that heritable change was possible regardless of its precise nature. That's the essence of evolution.

Then all the more reason to think Darwin made a mistake wrt the origin of light-sensitivity.

If Darwin knew that heritable change was possible, then why would he infer that light sensitivity was not another case of mutable heritable change?

BooBoo wrote:

Rumraket wrote:We now understand that Darwin had a bad reason for thinking how nerve cells became sensitive to light was of no more concern to evolution that the origin of life. We now understand that how nerve cells become sensitive to light is an intrinsic part of modern evolutionary theory.

Maybe. But Darwin did not think his mutation-selection mechanism could account for it.

And so what? Relevance does this have today? We now know that the mechanism of mutation(of base-pairs in protein-coding DNA or RNA) can make light-sensitive proteins, aka opsins, out of proteins that are NOT sensitive to light.

So Darwin was wrong about what he thought a mutation-selection mechanism could account for.

BooBoo wrote:

Rumraket wrote:That's because his principle of variation wasn't what we understand it to be today.

He believed in successive slight modification, which is how you believe a nerve cell becomes light-sensitive.

But he didn't know what was actually being slightly modified, or how. He didn't know that it was DNA being mutated, that that DNA was coding for the amino-acid sequence in proteins, and that that amino-acid sequence is ultimately what determines the properties of the respective protein, including which wavelengths of electromagnetic radiation it is receptive to.

Darwin didn't know that, so Darwin was wrong about what his "successive slight modification" could achieve. It turns out that it can, in point of fact, make cells sensitive to light.

BooBoo wrote:

Rumraket wrote:Do I have to repeat myself? We now understand how a cell becomes sensitive to light. It's because of mutations. What is escaping your comprehension here?

And Darwin knew of mutations (variations). What part of that don't you understand?

What I don't understand is what your point with this thread is.

Evidently, what you don't understand is that Darwin's knowledge of mutations was not the knowledge we have today, that while he believed the properties of organisms could change through mutations, he did not know how this happened and what effects this could potentially result in.

Darwin, together with Wallace, was a pioneer of the theory of natural selection and a theory of evolution based on this. He was a great scientist and did important field and theoretical work. But he was also fallible, he didn't know about the things that was found out after his death. For example, what the basis of mutation is, and how mutations can alter the properties of the molecules that make up the cell. He didn't know about that, so he made an inference that turned out to be wrong. Why is this so important to you? Is there some specific conclusion you want us to draw from Darwin's totally natural ignorance of subsequent developments in the field he helped establish?

Is it that "Hey, I just want to remind you that Darwin was wrong about something!" ?

Or is it "Hey, Darwin didn't think this could be explained by his theory so therefore it can't!" ?

Or something else entirely?

What is your point with this thread?

Rumraket wrote:

What is your point with this thread?

That's a very good question. I've been trying to work that out for a few days.

campermon wrote:

Rumraket wrote:

What is your point with this thread?

That's a very good question. I've been trying to work that out for a few days.

"Darwin woz evul bekause I think that Darwin and science is undermining my faith bekause I don't understand itt at alle and so I hate itt bekause deep down I suspect the scientists may be right". "But I don't want to admit that my fairy tale is a lot of bollocks to a lot of atheists who are evul and we can't be good without god and..........."

BooBoo wrote:

KeenIdiot wrote:Booboo, what is your problem with the second half of the sentence you quotemined?

How a nerve comes to be sensitive to light, hardly concerns us more than how life itself first originated; but I may remark that several facts make me suspect that any sensitive nerve may be rendered sensitive to light, and likewise to those coarser vibrations of the air which produce sound.

I just am amused as to why Darwin considered the first hurdle to be overcome in the evolution of the eye to be a problem akin to how life first began. I have no idea what "facts" Darwin alludes to that could render a cell sensitive to light or sound.

I'm amused at Newton's difficulty in understanding how gravity can act at a distance. He must have been wrong about everything else, no?

campermon wrote::rofl:

"..............AND I am going to die and there is no heaven....."

{main bus undervoltage detected}

<warm restart........>

"Hark the Herald angels sing, glory be to the newborn King..."

[Happily back in delusion space].

BooBoo wrote:Although it is generally accepted that the origin of life is unrelated to the theory of evolution by natural selection, contrary to the claims of creationists, Darwin seemed to have a more nuanced view on the matter in Chapter 6 of The Origin of Species.

"How a nerve comes to be sensitive to light, hardly concerns us more than how life itself first originated."

The context of this quotation is, of course, the evolution of the eye. Darwin appears to suggest that the origin of specialized light-sensitive cells (i.e photoreceptors) - a critical first step - is akin to the problem of how life began.

There is nothing here even to suggest that Darwin thought of biological complexity and the origin of life as the same issue. All Darwin says is that that one issue concerns him about as much as the other issue. He does not suggest that there is some similarity in explanation. He is just talking about relative levels of concern.

There is nothing to discuss here, as the entire OP seems based on a complete misreading of a sentence. Darwin could just have easily said "How a nerve comes to be sensitive to light, hardly concerns us more than how neurons, in the aggregate, seem capable of producing human consciousness", meaning that both are big problems that he wants to solve - and the fallacious misreading in the OP would have been harder to make.