Does Biological Evolution Presuppose Scientific Naturalism?

It has been a while since I debunked a creationist or defended naturalism from creationists intent on misrepresenting science, but an article that was recently sent to me by Nirmukta member Sajith Unni gives me an opportunity to do both. The relevant portion of the article is this:

In Darwin on Trial, Johnson drew out the suspiciously sequestered fact that Darwinism presupposes a naturalistic worldview. Naturalism, as a worldview, says that nature or matter is all there is; the supernatural does not exist or, if it does, is entirely irrelevant to life in the natural realm. Johnson deftly pointed out that naturalism is not a scientifically deduced fact but rather a philosophical presupposition.

The first result of Johnson’s contribution was to expose the atheistic scientists’ philosophical presupposition of naturalism and separate it from their science. Like the lad saying the emperor has no clothes, he identified the philosophy masquerading as science and pointed it out. More far-reaching, though, Johnson gave birth to the scientific movement of intelligent design theory (ID).

The theory of intelligent design holds that certain features of living things are best explained by an intelligent cause, and not by an undirected process such as natural selection.

The author of this article deliberately conflates different versions of naturalism, as often do most critics of naturalism in general. A philosopher of science will be aware of these different versions, such as ontological or metaphysical naturalism, epistemological naturalism and scientific naturalism. Opponents of science, even if they know the distinctions between the different types of naturalism, will lump them together when debating scientists. This enables the creationists and the like to argue against a form of naturalism that does not actually apply to the case in question. That is, they use the fact that most people don't know the differences between the distinct forms of naturalism, to create straw men arguments. In the case in question, the author is arguing against metaphysical/ontological naturalism (a hard stance that could in its most extreme form be said to presuppose the idea that nature is all there is), when in fact the relevant form of naturalism in this context is scientific naturalism (also known as methodological naturalism). Let's take the statements individually:

"In Darwin on Trial, Johnson drew out the suspiciously sequestered fact that Darwinism presupposes a naturalistic worldview."

Evolution by natural selection does not presuppose any worldview that is not also presupposed by science. But science does not presuppose any worldview! Science only presupposes certain philosophical rules of logic that are based on the empirical tradition. These are not worldviews, but the foundational principles of science that are subject to revision if the evidence does not fit them. What we discover is that rather than presupposing naturalism, science necessitates a certain naturalistic worldview based solely on the success of the scientific method.

"Naturalism, as a worldview, says that nature or matter is all there is; the supernatural does not exist or, if it does, is entirely irrelevant to life in the natural realm."

Firstly, as mentioned above, the author is talking about metaphysical naturalism here, which is not based on the scientific method and therefore implies that the argument is a straw-man in this context. But let us analyze the statement nevertheless. Nature is not synonymous with matter. The scientific understanding of nature is a lot more complicated than that. To demonstrate the absurdity of the claim made by the author all one needs to do is to point out that scientists believe that the universe contains anti-matter. Scientific naturalism is not the idea that matter is all there is. It is the idea that all we can know about the natural world it is possible to know only through systematic study of the natural world. No one has been able to design a scientific experiment or even make an observation that can determine if there is any supernatural world, or if there is another medium responsible for communication between the natural world and any possible supernatural world. That is, all things in the natural world have natural causes as far as we can tell, and no one has proven otherwise. This is a simple enough concept that anyone except creationists can easily understand.  

"Johnson deftly pointed out that naturalism is not a scientifically deduced fact but rather a philosophical presupposition."

So which is it- a fact or a worldview? On this point the author is relying on the lamentable fact that many who believe in the validity of the scientific method are clueless about philosophy. The truth is, there are many philosophical presuppositions that are built into the scientific method, but the naturalistic worldview is not one of them. The naturalistic worldview, unlike the logical presuppositions in science, follows from adopting the methods of science as the most reliable tools we have for understanding reality. I will quote from Tom Clark here:

It’s important to see that naturalism depends on taking science as your way of knowing about the world and what ultimately exists in it. Scientific explanations tend to unify our view of what exists, since once something gets understood scientifically, the connections between it and the rest of what science understands are made clear. This is what science does: to show the pattern of connections between different things. These connections are sometimes literal physical connections, such as how our bodies are put together, and sometimes they are causal connections, such as how the wind causes a sailboat to move. Either way, science inevitably unifies the constituents of the world into a single whole, in which everything is either closely or remotely connected to everything else. It doesn’t and can’t show that there is a separate supernatural realm, or some sort of supernatural stuff that is categorically different from what’s in the physical, natural world. So, science is the basis for naturalism. If you take science as your preferred way of knowing about the world, you’ll be led to naturalism.

"The first result of Johnson’s contribution was to expose the atheistic scientists’ philosophical presupposition of naturalism and separate it from their science."

The past 4 centuries of scientific study have shown us that the observable universe functions in scientifically predictable ways, as observed using the scientific method, which is all the information we need to determine that the naturalistic worldview is accurate. The scientific method is what provides the ultimate logic behind the epistemology of naturalism, which declares that anything that can be known about the natural world must have natural causes. This makes any non-naturalistic worldview a superstitious and faith-based view of the world. The methods of science uniquely determine the philosophy of scientific naturalism. Science does not presuppose naturalism. Quite the contrary, scientific naturalism is an epistemological understanding that is inextricably linked to the scientific method.  

"Like the lad saying the emperor has no clothes, he identified the philosophy masquerading as science and pointed it out."

He has not done anything of the sort, as I have indicated in my analysis. Scientific naturalism is intact. If the emperor has no clothes, then science and reason will determine that fact, for sure. If anything, this particular creationist attempt to disprove evolution by attacking scientific naturalism is akin to attempting to prove that the emperor has no clothes by arguing that clothes do not exist. 

Now for the creationism part:

"More far-reaching, though, Johnson gave birth to the scientific movement of intelligent design theory (ID).

The theory of intelligent design holds that certain features of living things are best explained by an intelligent cause, and not by an undirected process such as natural selection."

ID never was nor ever will be a scientific theory, and not because it violates scientific naturalism. ID is not a scientific theory because it violates scientific methodology. Here are some of the methodological principles of science that it violates:

1. Testability: As mentioned above, there is no scientific test for the supernatural.

2. Predictability: ID makes no future predictions that can be tested.

3. Falsifiability: There is no way to falsify the idea that 'god did it'.

These are the most fundamental requirements for a scientific methodology, and ID satisfies none of them. On the other hand, biological evolution has become the cornerstone of modern biology because of how well it has stood up to analysis using the scientific method. The evidence for evolution is stacked up higher than for any other theory in biology. The fossil record, the genetic analyses, studies of geographic species distribution, experimental evidence and all the mathematical modeling studies, prove beyond a shadow of doubt that biological evolution is one of the most robust theories in modern science.

And contrary to the creationist article's claims, natural selection is anything but "undirected". That is one of the most ignorant notions about evolution that anyone can profess, and it's not to the credit of the ID movement that this is such a common misunderstanding. It's almost as though creationists as a group are unaware of the meaning of the word 'selection'.

Geographical Distribution of Related Primate Groups

Scientific Naturalism can help us make epistemological judgments about the natural world. ID, on the other hand, is simply an appeal to unknowability. Anyone who suggests a supernatural cause for a natural phenomenon is simply saying 'it's magic'. In science, 'it's magic' is a non-answer. It does not increase our knowledge in any way whatsoever. But I'm presupposing that ID proponents want to increase knowledge the way scientists do. I guess that is one presupposition that I am guilty of.

"Fossil rabbits in the Precambrian" 

- J.B.S. Haldane, when asked to falsify evolution.