Question

Hello Rabbi Michi,
I came across a critique of God Plays Dice and couldn’t find a response to it, and I’m confused.
On the face of it, it seems clear to me that the critic is right (what he says is simple logic).
Did the Rabbi make a mistake in what he wrote?
 
Here is a quote from the critique:

It seems that the heart of the argument is the following paragraph:

Every evolutionary step that produces a non-viable mutation leads to a complete halt of the process, cutting off the entire evolutionary chain. In the evolutionary process we have no mechanism that ensures that each time the species will somehow get back on track. If at one of the stages in history no survivable mutation is produced, the entire process stops permanently.

What Abraham is talking about is a model of evolution. In this model, almost every mutation produces a creature that is not viable, and therefore cuts off the evolutionary lineage it might have led to. Only very rarely does a mutation succeed in producing a viable organism. Therefore,

We are dealing with a sequence of events in each of which the process has an almost zero chance of not going extinct, and all of them have to accumulate one after another without a single failure in order to reach what is defined as “success.”

I am again and again shocked by the low level that apologists allow themselves. There are explicit mathematical models of evolution—so why does Abraham, who has the background to understand them, engage not with them but with pathetic caricatures? Of course, in those models, evolution does not stop just because a destructive mutation occurred in one particular organism.

But even within his own model, that conclusion does not follow. At the base of the model lies the assumption that mutations will almost always lead to ruin—and therefore, Abraham argues, the whole process will stop. Let us build a simple model based on that assumption and see whether that is indeed the result. But unlike Abraham, let us remember that evolution operates on populations, not individuals.

Suppose that in generation 0 there is a population of size N0. Suppose each individual has, on average, No offspring. Suppose there is a probability p that a given offspring will have a lethal mutation preventing it from producing offspring. If so, then in the next generation there will be

N1=(1-p) No N0

offspring. That is, the population will grow or shrink depending not only on the probability of a lethal mutation but also on the average number of offspring. For a species that produces two offspring on average, the population will shrink only if the probability that each offspring has a lethal mutation is greater than 50%! Needless to say, in nature most newborns are genetically healthy and lack such a mutation. The conclusion that a large number of destructive mutations will bring about the collapse of the whole process is therefore absurd. (By the way, most mutations are neutral, and destructive ones are rare—but why let facts confuse us.)

This model too is extremely poor for understanding evolution, since it does not include its main component—natural selection. It is obvious that once a mutation arises that increases the number of offspring, it will spread quickly through the population. Therefore, even if such mutations are rare, they can build on one another. And as noted, a high frequency of destructive mutations, even if it did exist, would not necessarily stop this process.

The important point is that what happens depends on models, and on the values of the parameters in those models. One cannot infer so simply that the existence of many destructive mutations will cause evolution to stop or populations to go extinct. To argue that seriously, one has to show that this is what happens in realistic models. Abraham does not even try to address the real models biologists use*, and therefore his argument is not even worth a serious response. In the real models, there are empirically grounded percentages of empirically grounded processes, and there is no stopping of evolutionary processes there.

Abraham is, among other things, a respected physicist. He would never dare (or be able) to publish an article (or a book) that discussed physical models in such an imprecise and unserious way. But when it comes to apologetics, anything goes. Anything in order to justify his prior beliefs. He allows himself to ignore the real models and put in their place a skeleton that does not even deserve the title of a straw man.