bluefugue

Darwin did not believe it to be absurd. As you note in the second half of your sentence, he merely conceded that on first blush it seems to be absurd -- the concession made only so that in the following sentences (which you omitted) he could demonstrate this appearance of absurdity to be without good cause.

One of the ways to conduct an argument is first to lay out all of the opposition's points, and then refute them. In fact that is the approach Darwin took throughout the chapter you quoted from, which is entitled, appropriately enough, "Difficulties on Theory." Darwin can't respond to the difficulties without first laying them out. But to quote only the laying-out, and not the response, completely misrepresents the point he was trying to get across. It's selective quotation, designed to imply that the author meant something other than what he really did. Ergo it is misguiding, ergo it is dishonest.

[ January 13, 2002: Message edited by: IesusDomini ]</p>

Oolon Colluphid

David, you claim to have read my posts explaining how eyes (or any other complex thing in nature) are thought to have evolved: step by step, each ‘forward’ step an improvement on what was already there. And this X' from X'', X'' from X''', and so on. Given enough lineage, the eye may potentially be derived from something extremely different from the present form.

Chance is the variations, the copying errors. These we know to exist. The bit that leads from a population of mostly X''s to X's is non-chance. If X's have an additional survival value, it is inevitable that (all other things being equal) they will spread through the population. This mechanism has also been shown to exist. To repeat Darwin: "Reason tells me, that if numerous gradations from a simple and imperfect eye to one complex and perfect can be shown to exist, each grade being useful to its possessor, as is certainly the case; if further, the eye ever varies and the variations be inherited, as is likewise certainly the case; and if such variations should be useful to any animal under changing conditions of life, then the difficulty of believing that a perfect and complex eye could be formed by natural selection, though insuperable by our imagination, should not be considered as subversive of the theory."

Clear now?

Note that we have not shown that it did happen this way. What we have shown is that logically it is perfectly possible, without recourse to anything except known natural factors. So it is the more parsimonious hypothesis, not requiring supernatural beings and events.

But it’s more than that. This mechanism of building on pre-existing structures has greater explanatory power, explaining the distribution of 'design' features through the natural world (since they pass down some lineages but not others, and also the huge range of design oddities and cock-ups found in nature -- and why they too are found in the groupings they are (eg why cephalopod molluscs have a right-way-round retina and also have gills which are not countercurrent).

It also has coherence with other areas of scientific knowledge (eg genetics's understanding of mutations).

And it has predictive power: we would expect that eg a newly discovered cephalopod species would also have these features. Though he didn’t fully know it, Darwin’s mechanism predicted that genetics would work in the digital manner we now know it does.

So evolution is vastly superior to creation as an explanatory theory.

TTFN, Oolon

Christopher Lord

I think the question of the original post: " Do half of you really know what you believe?"

has been answered. I'm not too sure on the ratio, but I think the majority who have responded have a good grasp of what they believe.

I cant help but wonder if the question can be turned around on theists, and whether they could answer with the same completeness. I would wager the first question would result in a stalemate, in fact!

"Which religion is the one true religion, and if yours, why yours?"

I would love to see that answered--in another thread.

[ January 14, 2002: Message edited by: Christopher Lord ]</p>

Oolon Colluphid

I think it's worth pointing out to davidH that I (and I suspect most who’ve replied) don’t believe evolution. We accept it (common descent) as a fact overwhelmingly supported by evidence, and evolution as the best available Theory to account for this data.

The reason I think that’s worth pointing out is that ‘believe’, when talking to theists, is such a laden word. Unlike theirs, ours is not belief as in ‘leap of faith’. You could call our acceptance of it ‘belief’, but it is almost the opposite of what theists mean by belief, ie something you do (even) in the absence of evidence.

TTFN, Oolon

davidH

Yeah, you say overwhelming evidience but I haven't found out how the eye could have feasibly evolved by mutations (blind chance) and then natural selection.
Sure you have made suggestions but the more complex we go the less likely it seems that it could have happened - to me anyway.

But as yet I'm still reading.

Yo, anyone out there know a site or any info on how much DNA it take to code the eye?
Like counting all the bases? Just out of curiosity.
Even if it's only an estimate I'd be grateful.
Also if you can tell me how many bases it takes to code 1 cell - any cell will do.
Thanks, it's just that in the reading I can't find any reference to it.

Vorkosigan

[QUOTE]Originally posted by davidH:
Yeah, you say overwhelming evidience but I haven't found out how the eye could have feasibly evolved by mutations (blind chance) and then natural selection.

What is this, argument by incantation? Once again, mutation is not "blind chance." Mutations are caused. Natural selection processes are determined. "Chance" operates nowhere in this process. No "chance" here at all.

Instead, what one has is positive feedback loops, based on selection processes. Visual systems are selected for because they offer powerful advantages for those animals that have them.

As we have already pointed out, there are thousands of different visual organs used by animals spanning the whole range of complexity from light-sensitive cells to the pinnacle of eye creation, the squid eye. Thus, we know all of the intermediate forms could have evolved, because we can go out into the world and see them for ourselves.

So really, your objection is "I refuse to believe."

What we need from you is hard evidence showing that the human eye could not have evolved from intermediate forms we know exist.

Michael

davidH

Yeah, mutations are caused but where on the DNA strand they cause the mutation is blind chance.
But if you have any proof that where on the DNA strand they cause the mutation is not blind chance then I would like to have a look at it. Cause that's what I've been wanting - what could have caused the DNA strand area that contained the information about the eye to mutate in away that it caused no damage but actually caused it to evolve.

Plus you know about the amount of DNA there is in a single cell or even that makes up the eye? I'd like to find out.

Vorkosigan

Originally posted by davidH:
Yeah, mutations are caused but where on the DNA strand they cause the mutation is blind chance.

We went over that. All mutations are caused. No blind chance involved.

But if you have any proof that where on the DNA strand they cause the mutation is not blind chance then I would like to have a look at it.

Cause that's what I've been wanting - what could have caused the DNA strand area that contained the information about the eye to mutate in away that it caused no damage but actually caused it to evolve.

First of all, a mutation is a mutation. It is beneficial or damaging in relation to some environment, not in relation to some organism. A mutation that makes you go blind is a disadvantage on the savannah, but an advantage in a lightless cave.

Second, please explain how you know that the location of the mutation is "blind chance."

Michael

tronvillain

I think he's saying that mutations seem undirected i.e. the result of "blind chance", which is not an unreasonable statement.

lpetrich

That's one seriously-proposed hypothesis for aging and the death that results. In effect, many organisms have a built-in hara-kiri mechanism the way that cells do (apoptosis or "Programmed Cell Death").

And yes, dying soon after reproducing is a common strategy -- consider annual plants and salmon. A more dramatic example is female octopuses, after laying their eggs, will stop eating as they guard those eggs, eventually dying.