Chapter 4 – Natural Selection

What is Darwin’s point in chapter 4?

In the longest chapter of the book, chapter 4, Darwin introduces the concept of Natural Selection.

“This preservation of favourable variations and the rejection of injurious variations, I call Natural Selection.”

“Natural selection can act only by the preservation and accumulation of infinitesimally small inherited modifications, each profitable to the preserved being; and as modern geology has almost banished such views as the excavation of a great valley by a single diluvial wave, so will natural selection, if it be a true principle, banish the belief of the continued creation of new organic beings, or of any great and sudden modification in their structure.”

One of the main things that Darwin is challenging in the book is the creation theory of life. But, I cannot discern exactly what is meant by this theory. In the passage above, it seems to imply that novel life is continually being created. In other places, he implies that a creator created every single species exactly as they are.

He states that Natural Selection would be a slow process.

“That natural selection will always act with extreme slowness, I fully admit.”

However, I do not see why this should always be the case. And he does not demonstrate why this should be so. In the case of “artificial selection”, man has been able to change life relatively quickly. So, by principle, changes can be quick.

In this chapter is the only diagram in the book, in which he talks about his trees.

“The affinities of all the beings of the same class have sometimes been represented by a great tree.”

It is to be noted that he does not at this point claim that all life comes from a single organism. Rather, he only makes a claim that the same “class” can be represented by a tree.

goat wrote:From the information he had, even with the man’s intervention, it was generations. I think you are looking at ‘slow’ when it comes to what our modern thinking of time is. Slow is such a relative term, so when he says ‘slow’, it could very well be looking at it from a lifetime of a single man.

I think one problem overall with the book is that he remains ambiguous in several terms, slow would be one of them. But, I think when he says slow, he is thinking on the order of thousands/millions of generations.

Referring to his diagram, he says:
“In the diagram, each horizontal line has hitherto been supposed to represent a thousand generations, but each may represent a million or hundred million generations, and likewise a section of the successive strata of the earth’s crust including extinct remains.”

However, we certainly see that in artifical selection, thousands of generations are not required for morphological changes.

goat wrote: However, this just shows he did not have the information for quicker selection in nature.

I would go farther and say that he did not have much evidence on any type of natural selection, whether it’s slow or fast.

The primary evidence that he has presented so far for selection is human selection. The rest that he has presented have been arguments and conjectures. Since artificial selection is “quick” (not on the order of thousands of generations), it is interesting that he would make such a strong statement as “that natural selection will always act with extreme slowness, I fully admit.”

I want to get back to what he is primarily countering in the book. He does not explicity state what is the creation theory. I would guess that it was common knowledge at that time. Though I would assume it was something close to the Biblical version.

However, this statement “belief of the continued creation of new organic beings” is not compatible with a Biblical creation. And would even appear to be a strawman argument.

goat wrote:I would wait on the evidence he has. Right now , he is setting up what his theory is. Until you read how he supports his theory, you don’t know the evidence he is going to provide.

Actually, I’ve already finished reading the book. But we’ll wait to discuss the future chapters as they arise and discuss if evidence is brought forth.

I am sure that the ‘belief in the continued creation of new organic beings’ is probably something that was common in those days. In chapter 4, he provided hypothetical examples.

As I read through the book, I kept getting the impression that the creation theory that he is attacking is not the Biblical notion of creation. He might falsify the popular notion of creation, but he did not necessarily falsify the Biblical creation theory. This is one example of that. The Bible does not say that new organic beings are continually being created.