Is naturalism a type of faith?

By on April 25, 2012

In this essay, I’m going to take on a common claim that a form of narrow naturalism can rightly be called faith. The form of naturalism I have in mind is one that says for any given unexplained event, it is overwhelmingly likely that the real explanation will be a naturalistic one. So, for example, such a person would claim that something natural probably caused our universe via the Big Bang or other means. Or they would claim that something natural probably brought about the origin of life on this planet. These are events currently not explained by science, but the narrow naturalist is confident that science can one day explain them, if the opportunity actually presents itself.

I don’t want to get too mired in a discussion of what we may rightly call faith, so I’ll just consider whether that confidence in science’s explanatory capability is justified and to what extent it is justified. If the belief is very justified, say at a probability of 0.75 or higher, then I don’t think we can rightly call it faith under any definition except those that are too all encompassing to be useful.

What will be our method of determining this probability? You probably guessed it, if you’re a regular reader—Bayes’ Theorem! If you just read that and thought, “WTF is Bayes’ Theorem?” then you may want to start here, here, and here to see my attempts at instruction.

As a reminder, here is Bayes’ Theorem, and the sections below will attempt to replace these abstractions with real numbers so we can run the formula:

p(h|e.b) = p(h|b) x p(e|h.b)  /  [ p(h|b) x p(e|h.b) ] + [ p(~h|b) x p(e|~h.b) ]


Prior Probabilities: p(h│b) and p(~h│b)

To determine our prior probability, we’ll use Laplace’s Law of Succession. This offers a great advantage in determining our prior probability compared to situations that require more subjectivity. Laplace’s Law is p = (r + 1) / (n + 2) where r is the number of times in past trials that an outcome has occurred and n is the total number of trials. I’ll give a quick explanation: If you were rolling a die that you knew was biased, but weren’t sure toward which number, you could test it by rolling it several times. Let’s say that the 6-side is rolled 47 times out of 100 rolls. The expected prior probability of rolling a six is 1/6, but on this particular die we see it’s 48/102 or simplified is 8/17. When you have past data, Laplace’s Law is a good way to provide an objective prior probability.

Now, in the case of naturalistic explanations, we have an extensive track record. In fact, everything that has ever been conclusively explained has been done so by a naturalistic process. This includes the birth of every person, the formation of rivers and mountains, diseases, genetics, the outcomes of wars, and on and on. All of these things used to be attributed to the acts of gods or other divine creatures, but are now understood as natural phenomena. This means that using Laplace’s Law, r and n are the same. This can quickly get out of hand because so many things have happened like these in the history of Earth. I’m going to limit my occurrences to 100 billion. That’s the number of people estimated to have ever lived. So, even if we were only counting the number of sneezes that have ever occurred, we would be justified in using this large of a number. If we run Laplace’s Law, we get a result of p(h│b) = 0.99999999999. This is the probability that our hypothesis of narrow naturalism is true given our background knowledge of history and science.

The other number we want here is simply derived from the previous number: p(~h│b) = 1 – p(h│b) = 0.00000000001. Now we have two of the four terms necessary to calculate an answer.


Consideration of Evidence: p(e│h.b) and p(e│~h.b)

We’ve just seen that prior to considering any particular example, like the Big Bang, naturalism has a significant statistical advantage in its potential to explain based on a strong track record. What this tells us is that even if we are very generous to the opponent (like a supernaturalist) in the consideration of evidence, h (narrow naturalism) should still come out as much more probable. So, let’s try and be generous so that no one can accuse me of bias. I’m going to offer three sets of possible numbers that stack the deck in favor of supernaturalism by making the likelihood of evidence given ~h way more probable than the likelihood of evidence given h.

Scenario 1

p(e│h.b) = 0.01

p(e│~h.b) = 0.99

Scenario 2

p(e│h.b) = 0.001

p(e│~h.b) = 0.999

Scenario 3

p(e│h.b) = 0.0001

p(e│~h.b) = 0.9999



Now, we are able to solve for p (h│e.b), which stands for the probability our hypothesis of narrow naturalism is true given available evidence and background knowledge. I’m going to show the outcome for all three scenarios:

Scenario 1

p (h│e.b) = 99.999999901%

Scenario 2

p (h│e.b) = 99.9999990009999%

Scenario 3

p (h│e.b) = 99.9999900010002%

Even in the best case scenario, the result of the confidence we should place in narrow naturalism being true given history is practically 100%. And that is with the likelihood of available evidence being 9,999 times more probable under supernaturalism!

Unless someone can start coming up with confirmed supernatural causes in the past (and it had better be a whole lot of them if they plan to make a dent in the probabilities), then narrow naturalism is incredibly well justified. To call this level of confidence faith is misleading at best, dishonest at worst.



When I view your RSS feed it puts up a bunch of garbage, is the issue on my end?


pallcumn, it seems to work for me using Google Reader. What type of feed reader are you using?


Wouldn’t “supernatural” causes just be natural causes for which the observers do not yet have natural explanations? I don’t disagree with you, I just think you’ve woven yourself an impermeable basket here. If something can be demonstrated, it is natural by definition.

If some other person wanted to make a supernatural claim, then they would need to present some evidence, and the moment a phenomenon of any type is demonstrated, repeated, measurable, or detectable, it ceases to be “super” natural. You can’t lose. And I don’t think you can lose anyway…

Now I am going to spend the week thinking about “supernatural sneezes” and how I would differentiate such an event from a normal sneeze.


Thanks for the comment! I understand your concern. I thought about this issue, but ultimately I think the argument still stands. Here are a couple of brief reasons why. I had to be a bit quick, but hopefully these at least start to get into the justification for my assessment going the way it did.

We aren’t only allowing scientific explanations to count as knowledge. Things taken as consensus knowledge from other fields, like history or philosophy can certainly count as well. If some other field (or some other path to knowledge) can produce a conclusive result, then they would have a counterexample. Keep in mind, though, they’ll need a whole lot of them to start tipping the probabilities in their favor. So, even if we allow for something like 10,000 confirmed cases of supernatural causes, we still are justified in assuming narrow naturalism for any given phenomena.

It didn’t have to be this way. There was a large span of time when people tried to gain knowledge in other ways. It just so happens that science, and to a lesser extent history and philosophy, has been WAY more effective at creating consensus background knowledge. But there is no necessary connection in place. It could have been different and still can be. All someone has to do is show us reliable knowledge that says otherwise. If it can come anywhere close to the type of consensus we have for the knowledge that sneezes have natural causes, then I’d say it’s fair game to go into our background knowledge and affect the prior probabilities.

I bring this up because it may seem like I’m stacking the deck, but that’s only a result of our backward looking perspective. It seems that way now because of just how successful science has been and how much of a failure other attempts to provide knowledge have been. We indirectly test supernatural claims, like prayer, horoscope accuracy, etc. But they just don’t provide consistent results.

Finally, I don’t think it’s just a case of supernatural causes just being those without explanation. There are plenty of attempts to provide explanation and they never work out. And remember, these are natural phenomena in question. Perhaps there is a supernatural realm with supernatural effects, but we want to know about what caused natural effects and the narrow naturalist assumes it is going to probably be a natural cause in each case. The Big Bang (or whatever caused the universe), biological life, stories written about Jesus, etc. – these are all things existing as part of the natural world. Go back to the claim of the narrow naturalist – For any given phenomena we encounter (implied that it’s in the physical world), it is overwhelmingly likely that it will have a natural explanation. In the end, it’s not much more complicated than saying things will keep on turning out like they have in the past.

Also, I’ve got you covered on the supernatural sneeze (sort of):


These ideas really try my limits. I am in no way a supernaturalist. I suspect that we are in agreement about everything anyway. What tickles some neuron way in the recesses of my mind is that your view seems somehow impermeable, unbreakable, or unfair. Which makes me think that we are tinkering with definitions, or being semantic when we discuss this.

If there is a supernatural realm where supernatural causes have supernatural effects and the realm, cause and effects are inaccessible to us, by definition. Then we have no basis for making any claims about its supernature. Funny how no one ever throws that term around, huh? Supernature.

We KNOW that there is something called nature, however. And it’s realm, cause and effects are ALL available for study.

Now a supernaturalist claims that there is an interaction between the realm of supernature and nature. And, most importantly, they claim to have knowledge of this interaction.

Generally these claims take this form: our thoughts and behavior are observable by entities in the supernatural realm. If these thoughts and behavior are pleasing to entities in the supernatural realm, then actors in the supernatural realm can influence events in the natural realm. Further, these actors in the supernatural realm have characteristics that we can detect (somehow). They are eternal. They are “good” and “evil.” They have this power or that power and so on… They wrote THIS BOOK. They hurl lightning. They control the weather.

See… now I don’t know what I am getting at.

The dream of supernaturalists is to have supernatural causes and natural effects. Further, for the mechanism of interchange to be understood only by themselves. But that, to me, just sounds like a natural cause and effect with a deliberately mystified mechanism.

I don’t feel like I’m playing a semantics game or anything. This is really just a post explaining why the intuition that all of us have anyway is justified by probability. Think about a car mechanic who gets a car that won’t start. She or he searches and searches for days and can’t find the problem. Does she or he conclude at any point that a demon got into the engine and possessed it? No, we would laugh at a situation like that. What I’m saying is that for every car that comes into a shop, for every broken tv remote, for every blade of grass, for every sickness, etc. it is WAY more likely that there is a natural explanation. If a supernaturalist wants to claim there is a cause/effect relationship as you’ve described, then we can hear the claim and evaluate it. I’m basing my argument on the lack of success they’ve had doing that in the past and the vast amount of success had by natural explanations.
What happened to inspire this was someone told me a story about a Buddhist monk that could float. My immediate reaction was that even if this is true, I wondered if there was a natural explanation lurking there undiscovered. Then I started thinking about how we use probability in general and Bayes’s Theorem in particular to predict future events based on the past.
The person arguing this with me made a claim about me having my own faith. I said that would only be true if I made a broader claim about naturalism. However, this narrow claim I’m making only requires a few assumptions and none of them beg the question against the supernaturalist:
1- that probability can provide justification for beliefs
2- that natural explanations really have been successful, as I’ve described
3- that supernatural explanations really have not been successful in providing consensus knowledge, like the knowledge of how grass grows or how water evaporates
If you agree with me on these assumptions, and I think they’re pretty solid, then the conclusion from Bayes’s Theorem should follow. Remember that I’m not making a larger claim that says only natural things exist – period. That isn’t really verifiable. Rather, I’m making a smaller claim that says any particular thing presented to you that requires explanation will probably have a natural explanation. I think that claim is highly justified.

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