Something I just thought of recently (probably–pun definitely intended–due to my re-reading of Shattering the Myths of Darwinism by Milton). It deals with the issue of probability in evolution.
I addressed part of this once upon a time in this article. However, it is time for a little refresher. To begin with, let us first get some simple understanding of how the theory of evolution is “supposed” to work.
Firstly, let us take “natural selection.” Natural selection is the process by which the fittest of a species survive to produce more offspring.  In biology, both “fittness” and “survivability” are defined as the production of offspring. Thus, natural selection is basically a tautology stating “those who produce the most offspring”–the fittest–”are those who produce the most offspring”–survive. Put in that way, natural selection loses its explanatory power.
Regardless, let us assume that it is a valid point. What is important to note is that natural selection is not the mechanism by which differences in species are created. It is only the method by which (according to Darwinists) differences that are already there are “selected.” In short, natural selection requires something else to provide the changes in a species in order for the selection process of the species most adapted to the environment to occur.
So what causes the differences in species? Not superficial differences, but the actual changes that alter a species? The answer, according to Darwinists, is mutation.
So what happens is mutations occur in the DNA of an organism–specifically within the reproductive cells, as opposed to the body cells (e.g. a person who gets skin cancer from standing in the sun too long would not pass that on to his/her children because the reproductive cells are not affected). These mutations result in children who are different from the parent species in some manner. Leaving aside the question of whether or not mutations are ever beneficial in the first place, it is only at this point that natural selection could take over for the Darwinist.
As such, natural selection plays no role whatsoever in creating new variation within species. Mutation does that work.
And this brings us to the probability issue. Darwinists such as Richard Dawkins are more than happy to point out the obvious–that evolving from a simple cell to a complex organism in one leap is improbable to the point of being impossible. Darwinists therefore break up the method into several “small steps.” Each step is simple enough to become possible.
But when we apply this to a real-world concept, we see that breaking up probability in this sense doesn’t help the gradualist. To demonstrate that, we must first look at probability in general. In my previous linked article, I mentioned the way probability works in flipping a coin. There, we only have two options: heads or tails. DNA and possible mutations of it, however, are infinitely more complex than a simple coin toss. So, to illustrate that slightly better, imagine a 20-sided dice (such as you would find in an RPG game).
Suppose that you want to roll a sequence of numbers–say the integers from 1 to 20 in order. What are the odds of that happening? Since each step has a 1/20 chance, the odds for the total sequence are 1/(2020), or 1/104,857,600,000,000,000,000,000,000. In short, if you were to toss the dice 1,000 times per second, it would still take you longer than the age of 100,000 universes (given the current idea that the universe is between 15-17 billion years old). Thus, rolling this sequence is for all intents and purposes impossible.
If a 20-sided dice is that improbable, how much more so gradualistic evolution? How do Darwinists get around this?
Simple. While the odds of the entire sequence is that improbable, each individual step in the sequence has only a probability of 1/20. That is, when you roll the dice the first time, you have a 1/20 chance of it landing on 1. You can simply roll this until it comes up, at which point you “lock” the integer into the sequence. Now, you simply procede to the next step and roll until you get the number 2. Again, you’ll have a 1/20 chance for that. Once it comes up, you lock it in place too, and repeat.
Seen in this way, the odds of this sequence occuring become the sums of the probabilities instead of the products, or 1/400.
1/400 is not so improbable as 1/104,857,600,000,000,000,000,000,000. Therefore, the evolutionist claim, the series of steps is not so improbable after all, and gradualistic evolution could be possible.
Naturally, there are problems with this, the most glaring of which is the fact that the sequence must know that it should “lock” the integer in place when it rolls the correct one. This requires some kind of outside intelligence guiding the process; something that can in no way be considered “natural” or internal to the system of the rolling dice in the first place.
Secondly, when we consider once again the method of evolution we see that it does not allow this sort of thing to occur. Remember, we started out by showing that natural selection is divorced from mutation. Natural selection, even if working constantly, cannot create a new species until after the mutation has occured. That random mutation must be beneficial to the species in order for the mutation to be spread to many offspring, etc.
But herein lies the problem. Natural selection has no bearing on determining whether or not a specific mutation will occur. The mutation has to occur before the natural selection can work on it. Natural selection, therefore, has no bearing whatsoever on the odds of whether or not a specific mutation will occur.
Think of it this way: the odds of whether a light sensitive cell will randomly mutate do not change simply because a cell is placed in a lighted environment. The odds of the mutation remain the odds of the mutation regardless. It is only after the mutation has already occured that “nature” can then “decide” whether it was a beneficial mutation or not. It is just as likely that an organism will mutate away from a specific course than toward a specific course; indeed, it is more likely that this will be the case!
Again, consider the odds we’ve just looked at with the dice. For every 1 positive “mutation” we have 19 failures. This isn’t such a bad thing in the roll of a dice, but for a species it’s fatal! Having a mutation that does not go toward something better means that there is no survivability advantage granted to the species. Natural selection will select against these organisms.
This demonstrates that either “random” evolution is intelligently directed, or evolution can never be anything more than an ad hoc explanation after the fact. It can never be predictive because we cannot predict what the next number in the sequence will or should be (or, biologically, we can never predict what mutation will specifically occur, or whether or not it will be beneficial–not just in our environment today but for future environments that depend on the sequence being correctly established right now). Ultimately, gradualistic evolution can never be scientific because it is either a “just so” story or else it requires external intelligence to make it work.