Friday, July 9, 2010

"The Faulty Mechanism of Evolution"

This post is part of a series of posts that deal with some common Young Earth Creationist (YEC) objections to theistic evolution.  The impetus for these posts came via a comment from a reader on a previous post.  An index of all these posts can be found here.

Here I would like to address this part of Steve’s original comment:

[Y]ou must trust in literally million of totally random occurrences happening over and over and over again through out billions of years. Not to mention that all these random occurrences must take place in such close proximity to each other, and in such a small window of time on order for the two "new" male and female species to find each other and mate before they die. The odds of that are mind boggling. And to believe that this conveniently happened millions of times over? 

Evolutionists do not believe what Steve suggests above.  If what he suggests above were to happen, it would truly be mind boggling.  But this is simply not what evolutionists believe.  This argument shows a complete lack of understanding of the mechanisms behind evolution. 

This type of argument is very common among Young Earth Creationists, and betrays a complete lack of understanding of the belief they claim to dismiss.  How can someone dismiss evolution on the grounds of lack of evidence if they simply do not understand it?

Let me try to clear up three very common errors made by Steve and many other YECs.  The following three points are fundamental to evolutionary theory, and if one doesn’t grasp these points, they simply do not understand the theory.

1) Natural selection is a non-random mechanism
2) Evolution occurs primarily in groups
3) Evolution is a cumulative process

Natural selection is a non-random mechanism

Above, Steve is claiming that evolution isn’t plausible because “millions of totally random occurrences happening over and over and over again throughout billions of years” couldn’t create a new species.  He is totally correct.  Steve (and many other YECs) miss a key aspect to evolutionary theory: natural selection.  Natural selection is non-random because organisms that are able to reproduces more will pass their traits on to their offspring.   Organisms that cannot reproduce will die without passing on the traits that do not let them reproduce.   Evolution occurs when many random mutations are passed through the non-random filter of natural selection, producing a process that is not random.

Evolution is a cumulative process

It is very common for YECs to claim that evolution isn’t plausible because random mutations must occur over and over again, and the probability of this happening is just too small.  This claim falsely assumes that there is no mechanism for maintaining one mutation before the next can occur.  In fact, natural selection is just that mechanism.  Natural selection turns what would be a random process into a cumulative process.  Each mutation that is selected by the environment (because it provides a reproductive advantage) is a stable organism, which reproduces and introduces the mutation into the collective gene pool.

Evolution occurs primarily in groups

The claim made by Steve above falsely assumes that speciation must happen suddenly, where one individual produces another individual of a different species.  In fact, populations of animals gradually evolve, not individuals.   The most easily understood type of this kind of speciation is called allopatric speciation, where one group is separated from the main group.  Due to different environmental pressures, this separated group undergoes cumulative changes that are different from the main group. 

Putting it all together

So evolution occurs when the non-random mechanism of natural selection acts on random genetic variation, over long periods of time, and primarily in groups, not individuals.  If you miss any one of those elements, you simply do not understand evolution, and you are in danger of making ignorant accusations that simply don’t hold water

2 comments:

Anonymous said...

I dismiss evolution on the grounds that I just don't find it relevant or interesting. Its just stupid in the sense of boring to the core. I'm not saying I take the creation story in Genesis to be the infallible word of God or anything. It also seems unnecessary. Do I really need to know in what order God made this or that? To know that he made the world is enough. To know that he made mankind and put the knowledge of good and evil within us as a sort of innate law, that's enough for me. I don't need anyone to conjecture the details for me or whether he made birds or fish first. So in short, evolution is as irrelevant to me as the order of events in Genesis 1.

Anonymous said...

"Evolution occurs when many random mutations are passed through the non-random filter of natural selection, producing a process that is not random."

At the base level, since it requires random mutations, its still a random process. The quoted statement is like the kind of moronic argumentation that Calvinists use when they try to claim that their view of predestination doesn't involve any randomness. They say God chose who would be elect without any reference to anything about them. The only way to do that would be to roll some dice or flip a coin. But they insist that it was "according to the good pleasure of his will." It would still require an element of randomness in order to work if it is not going to have anything to do with any aspect or quality or property (or whatever other synonym you can think of) of the individual. If nothing about the individual is involved in the choice, IT IS RANDOM.

So it is with evolution. If the mutations are random, then evolution does work based on a random principle. Evolutions are so much like Calvinists. Most deny free-will. And now they take something that would have to be random and say it isn't random. They might as well just all join the Presbyterian church already.