pudmuddle said:
The real question at hand, to simplify it a bit-How many times would evolution have to get it right? We are talking astonomical odds.
The hurricane in the junkyard forming a 747 comparison comes to mind. Even given a few billion years to form, order does not magically arise from chaos.
Of course, Murphy's law does not always prove true. But how often in life do we find that simple "five minute job" turning into an all day lessen in patience?
In a perfect world, the gears would always grind smoothly along, but we live in a fallen world....
But that is where natural selection comes in. It's an algorithm to get design and defeat those long odds. Let's break it down for you:
"If, during the long course of ages and under varying conditions of life, organic beings vary at all in the several parts of their organization, and I think this cannot be disputed; "
Any argument? Every individual is different from every othe individual. Either by a small amount or a larger amount.
"if there be, owing to the high geometric powers of increase of each species, at some age, season, or year, a severe struggle for life, and this certainly cannot be disputed;"
Again, any argument? We all know that organisms reproduce ever so much faster than food supply can grow, and (with the recent exception of humans) most organisms never reach the age of maturity or reproduction. They are eaten, starve, succumb to disease, do not have enough water, freeze, roast, whatever. Some cases, like the maple tree in my backyard, are extreme. Each year it produces over 10,000 seeds. None of them make it to maturity.
"then, considering the infinite complexity of the relations of all organic beings to each other and to their conditions of existence, causing an infinite diversity in structure, constitution, and habits, to be advantageous to them, I think it would be a most extraordinary fact if no variation ever had occurred useful to each beings welfare, in the same way as so many variations have occured useful to man. "
Any argument with the logic?
Some of those variations are going to be useful in the competition and give a competitive edge to the individual lucky enough to get it.
"But if variations useful to any organic being do occur, assuredly individuals thus characterized will have the best chance of being preserved in the struggle for life; "
Logically, the conclusion is inescapable. Mountains of data show it to be true.
"and from the strong principle of inheritance they will will tend to produce offspring similarly characterized. "
This is the key. The good designs, the "improbable" occurences, get
preserved by inheritance. Offspring are not identical to parents, but they are similar, and part of those similarities are the good designs that worked for their parents. So you don't have to start from scratch each time. Instead of a tornado in a junkyard, you can build your 747 slowly, one piece at a time, with only those successful part 747s being kept so that you can add the next piece. In fact, that is how the wing of the new Boeing jets was designed. CW Petit, Touched by nature: putting evolution to work on the assembly line. US News and World Report, 125: 43-45, July 27, 1998.
Yes, we have been looking at natural selection:
"This principle of preservation, I have called, for the sake of brevity, Natural Selection." [Origin, p 127 6th ed.]
Try
Climbing Mt. Improbable by Richard Dawkins and the first 3 chapters of
Darwin's Dangerous Idea by Daniel Dennett. Ignore their atheism because it is irrelevant. Concentrate on the descriptions of natural selection and the data.
Since natural selection can work at rates up to
10,000 times what we see in the fossil record, there is plenty of time, even if the 5 minute job takes all day. Or all month, which is 10,000 times longer than 5 minutes.