The Importance of Methodological Naturalism

Ambient Irony has an excellent post on the subject of why methodological naturalism is important to science. The argument, which is dead on the money, is essentially that invocation of supernatural causes eliminates the ability to test a hypothesis because it relies upon the willful decisions of entities unconstrained by the boundaries of natural law. Long quote after the fold comparing a natural hypothesis from a supernatural one and why one is amenable to testing and one is not:

Science sets itself apart from other such attempts in that it constructs a system, a rigorous framework, in which we can build our understanding. The framework is based on metaphysical naturalism.

For Science does not permit of just any explanation. Science seeks to explain the world in terms of the world. For any event we observe, Science seeks an explanation in terms of other events we observe. Events that we cannot observe are precluded from our explanations.

So, for example, we observe that if we leave a piece of rotting meat lying about, after a few days we find it crawling with maggots.

Hypothesis: Maggots spontaneously form from meat if it is left undisturbed.
Hypothesis: Maggots are planted in the meat by invisible immaterial demons.

We have two plausible explanations, but they can't both be true. Why does this matter? Well, it matters because we want to know which explanation is the correct one. We can perform tests - experiments - to see if our Theory of Spontaneous Maggotation is true. We can put the meat in a tightly sealed jar and see if our maggots generate.

And, as it turns out, they do not.

We can repeat the experiment, and we find that while maggots appear in unprotected meat, meat in the sealed jar remains maggot-free. We can vary the experiment, and find that even if we do not seal the jar, but merely cover it with a cloth, there are still no maggots.

This means that the first hypothesis is incorrect. This hypothesis required only meat and time, which have both been provided, but with no maggots resulting.

What about our demons then? Well, they are invisible and immaterial, so they clearly would not be stopped by something as simple as a cloth. But a cloth does prevent maggots. What does this mean in demon terms? It means that we have observed intances where demons do not create maggots.

And that's all we can say.

The difference here is that we know the first explanation to be incorrect. We know it for certain. It is wrong. It is false.

The second explanation? Well, maybe sometimes the demons are busy inflicting cholera on the people of the next village. We don't know.

The difference is that the first is a natural explanation, and the second is a supernatural one. Natural explanations derive from natural causes, and we can control natural causes. Supernatural explanations derive from supernatural causes, and we cannot control those.

The meat is there. We gave it time. No maggots appear, so spontaneous generation is false.

The demons may or may not have been there. They are supernatural; we cannot preclude them; we may not even be able to detect their presence. We do not know, nor can we ever know, whether the demons are the cause or not.

The Theory of Spontaneous Maggotification is a scientific theory, and it is wrong. The Theory of Devilish Wormonising is not a scientific theory, because we can never know whether it is wrong.

Brilliantly explained and right on the money.