In principle, could Occam's Razor ever favor theism over rival hypotheses like naturalism? What conditions would have to be met for this to be the case?
BONUS: for those interested in naturalism vs. theism debates, see What are theistic responses to Graham Oppy's argument for atheism from naturalism? and What are Christian responses to Graham Oppy's argument for atheism from naturalism?
My two cents.
As @Conifold eloquently mentions, Occam's Razor is somewhat vague and notions of complexity somewhat arbitrary, so that given suitable criteria of complexity and simplicity almost anything can be the outcome.
NB. Occam was religious (a theologian) and almost certainly did not consider the principle as contrary to the existence of god.
EDIT: @Conifold's comment (in case it gets removed):
Simplicity of Occam's Razor is too vague a conception to favor anything in particular without specifying complexity criteria, so Occam's Razor is of any use only in small technical matters. At any grand level, like theism or even interpretations of quantum mechanics, what is favored is determined by chosen criteria and not by Occam's Razor. One can design their simplicity to favor whatever it is they want favored. "Whatever is going to seem right to me is right. And that only means that here we can't talk about 'right'", Wittgenstein.
Occam's razor does not favour any theory.
Occam's razor is just a simple, practical heuristic, which says that the more complicated the theory, the less likely a priori it is to be true.
This doesn't mean that a complicated theory cannot be true, but that absent sufficient information, a more complicated theory has to involve more hypotheses, each of which with a priori only 50% chance of being true. More hypotheses, means therefore a lower probability that all your hypotheses will all be true.
Thus, Occam just says that the best strategy to understand how the real world works is to start with as simple a theory as possible, test it, and only complexify our theory one step at a time as need arises.
Anyone who would have produced a theory as complex as Quantum Mechanics say 2,000 years ago would have had very nearly zero chance of success. Needless to say, this someone's chances of stumbling by accident precisely on Quantum Mechanics itself would have been equally near zero.
Complex theories also require more time and energy. Think of all the time and energy the Catholic Clergy spent in vain on deciding what the Catholic Dogma should be. What a waste of their time, at least if the idea was to produce a true theory, which maybe it wasn't.
Occam is just common sense.
EDIT
Concerning the prior probability of hypotheses.
For one hypothesis, there are two possible outcomes, true and false. In the absence of any relevant information on the frequency of occurrence of each possible outcome, each one is credited with the same probability. For two outcomes, it is 50%.
If there are several hypotheses, it gets much more complicated depending on the possible logical dependencies between hypotheses.
For example, the probability that two mutually contradictory hypotheses be true together is 0%. With 10 hypotheses which are logically independent of each other, each being 50% likely true, the probability that all of them are true is 1/1024, or 0.1%.
Simplicity is a highly suspect standard. I have encountered all sorts of rationalizations that a writer's preferred worldview is "simple" and competing ones "complex", on both sides of basically every major dispute.
The concern is that "Simplicity" is not an objectively measurable standard. See this answer: https://philosophy.stackexchange.com/a/93539/29339 Also this answer: https://philosophy.stackexchange.com/a/93499/29339 Simplicity is SUBJECTIVE, and evaluating it requires honest dialog to arrive at concurrence between open-minded disputants.
Note, all other standards besides Occam also fail some test cases. Karl Popper, when Quine demonstrated that falsifiability is not actually achievable, resorted to a reframing of Occam as the way to sort between competing hypotheses. Popper's reformulation is not based on "simplicity" but on predictive power. The more potential events a hypothesis would be INcompatible with, the greater its predictive power. Between two hypotheses that match the current data, the one that is most testable by being refutable through test, is the one Popper prefers.
SO -- theism, if it makes more testable and falsifiable predictions than an alternative, can be preferred. THAT is what theism needs to provide in order to be preferred via Popper's recasting of Occam.
Could Occam's Razor ever favor theism?
Certainly! The entire premise of the Intelligent Design movement is that it does, with respect to the origin of life and the origin of extant biological diversity. It can also apply to the origin of stars/galaxies, or to solving the fine tuning problem.
That said, care should obviously be taken to avoid using "God did it" to preclude further investigation. However, in some instances "God did it" is a far less convoluted, and more probable, explanation than can otherwise be arrived at. (At the same time, it needs to be noted that "God did it" needn't preclude asking "how did God do it?".)
Occam's Razor is about explanations, and explanations are about understanding how things work.
The problem with theism as an explanation for anything is that, rather than giving a "how", it almost sidesteps it entirely.
Take animals for example - biologists explain the features of modern day animals, and why the features are distributed the way they are, in part with the process of Evolution. Evolution is a model of "how". If we throw away evolution and say Theism is the answer, God is the answer, there's no longer a model of how, there's just almost a dismissive explanation: there is no model, there is no "how", it's that way because God wanted it that way.
And if it were some other way insead, the explanation for that would equally be "because God wanted it that way" - the theistic explanation works equally well no matter what you actually see. Whatever you see, "god wanted it that way". Satisfying explanations shouldn't work for EVERYTHING you might see, they should work explicitly for the things you do see, and they should do a much poorer job of explaining the counter-factual things you don't see.
None of this is to say explicitly that theism is incorrect, just why it's unsatisfying as an explanation. It's not a model, and it explains all possible observations equally well.
There isn't really a precise, settled definition for "Occam's Razor". I'm going to — initially — set aside any qualification like "all things being equal" (because that's such a big escape-hatch that it doesn't leave much behind), and start with "The simplest explanation is usually the best one". Or, if you like, "We consider it a good principle to explain the phenomena by the simplest hypothesis possible" (which Wikipedia helpfully tells me is from Ptolemy).
With that out of the way, throughout history, theistic and supernatural explanations have been widely accepted as the simplest explanation for almost everything. The universe is complicated. Satisfying "naturalistic" explanations require a great deal of understanding, and for most of us (or, let's be honest, all of us), that understanding necessarily includes a lot of over-simplification and assumption.
That's why, over hundreds of thousands of years, countless theistic and supernatural systems have arisen, in every human society — and why those systems persist over hundreds and thousands of years. They are the simpler ones.
I have a rock, here, on my desk. A river stone: smooth, gray, oblong. It's nice.
Consider the What of this rock.
From a scientific perspective, I know that it's probably basalt, and those sparkles mean there's some quartz in there.
I'm going to try to do this without resorting to Wikipedia. Let's see how it goes.
Hmmm, and, what... feldspar, I think, and some other things I don't remember.
Those are made up of elements of various sorts... silicon definitely, maybe calcium and sodium, and I think potassium. And there's oxygen in there, which is a bit weird because that's an important invisible part of the air around me. The oxygen makes fire, and I somehow need it to live... and anyway, there's some of that in the rock, but bound up in some way that won't cause fires and I definitely can't breathe it.
I know that this difference is because the elements are bound into molecules. I don't remember much about this, but I remember that different elements have different smaller particles. Neutrons, protons, electrons. There's a whole bit with electricity and charge there, but it doesn't matter right now, I don't think. The important thing is that the number of these different subatomic particles somehow (how? uh, honestly, no idea) causes the elements to behave differently. The protons and neutrons are stuck together by something called the strong nuclear force (which is, I'm told, fundamental), and the electrons stay in orbit (where they don't actually exist in any specific place, but kind of just as ... a probability cloud) around those due to a weak nuclear force. Or maybe the forces are the other way around. They're a basic fact of the universe, though, I know that.
Anyway, the electrons like to clump in energy-shells, which also like to be complete, and there's a pattern — I think 2 in the first one, and then 8 and the another 8 and I forget after that — and the electrons can be missing, or shared, and there's something about ions and anyway, this causes the different elements to bond into molecules, which can have completely different properties from their original elements. Or at least, mostly different. I'm unclear on how different, actually. The original element is important, I'm sure.
Anyway, these molecules: they're really little — like, so little that there's no way to make an optical device where I could see them. And, they're actually mostly empty space, between those particles, and also, they don't really touch each other, but somehow that makes a solid rock. Yes. Lots of different kinds of molecules, of different elements, with all those different properties, held together by various fundamental forces. That's a rock.
Or...
Stone is one of the basic building-blocks of the universe. You know, there's air and water and other water-like things, and wood and metal and stone. Maybe fire. Right here, what I've got is a nice example of stone. It's heavy. I mean, not as heavy as gold, but it's got a solid, satisfying heft. You can hit things with it, and it probably won't break, although if it does, it'll probably be a kind of sheer, jagged crack. Yep, that's rock.
What about the How? That is, how did this rock come to be?
The science: well, okay, it's basalt. I think that's volcanic? But, not like obsidian or pumice. Something that got more melted than that, maybe? Anyway, there are other types of rock, like some that is squished bones and shells of tiny creatures. But I'm pretty sure this was formed millions or hundreds of millions of years ago deep inside the earth -- which is (mostly) solid on the outside, but has complicated molten layers in the inside, which are not solid but dense enough that we don't really worry about it too much, except when there are volcanos. This rock might have been some other rock a billion years ago, and then got melted down and mixed up and spit up, and then maybe was part of a mountain, and then some small part got chipped off and eventually ended up in a river and got tumbled around for thousands of years until it got all nice and smooth.
Oh, but before that! Those elements! Where did they come from? Wellll, the complicated ones, those didn't exist at the beginning of the universe. Wait, actually, at the beginning of the universe there wasn't any stuff. It was just all super-dense — like, everything was everywhere all at once, but there wasn't any "everywhere" for it to be in! But not a pinpoint, because that assumes that there's some "not everywhere" that this was in the middle of. No, this was all there was and there wasn't an outside of it. But for some reason (yet unknown) that exploded and there started to be space for there to be stuff in, and there was eventually hydrogen. I'm not sure why, but it all kind of came together that way.
So: hydrogen: the first element. Then, that element started clumping into stars, and so some of the hydrogen got squished so much it transformed into a totally different element — helium! I think we got some molecules around that time, too, but as far as I know whatever helium-hydrogen molecules exist don't factor into my life much. (Except that there was recently a Jeopardy! clue about what two elements were in the first molecule, so I feel like I'm on pretty solid knowledge-ground here. Like, rock-solid, if you will.)
I'll fast forward a bit, but: the first stars explode, more stars start making even heavier and more complex elements, eventually we get planets made out of those elements, and one of those planets is the Earth on which I live, and my rock was part of that, made out of star-stuff (just like everything else around me).
Also, I'm actually not sure that this isn't one of those kinds of rocks that's made up of a lot of little shells, really squished. If it is, there's probably carbon in it. And this inert thing was once hundreds or thousands of living beings. But I think it's the volcano kind of rock, which is definitely not made up of living things even though the elements are pretty similar, give or take the carbon.
Or
Wow, that was complicated. It's just a rock, expressing its general rock nature. The simplest explanation is that the universe has always been here, and that there have always been rocks. Maybe something made them. They're pretty great, rocks. Makes sense that someone would want to make them, if they had the power to do it. Same with trees. Good stuff.
Don't get me wrong. I personally believe the complicated things about my rock. Even though I clearly don't really understand it. But it's so complex that this belief is really based on faith rather than experience. I do not mean this in some sort of wishy-washy "science is another religion!" sense. I think it's a well-justified faith: I believe that people have done careful, empirical research over centuries to test and verify all of that complexity. But, wow, it's complex.
So, let's consider the serious question: what's the purpose and meaning of this rock? Or: the Why.
Okay, so, finally, I can get simple with science! There is no why! The processes just happen, all of that stuff for billions of years, maybe some random chance bouncing things around, maybe some set pattern locked in at the beginning of time — maybe even something that repeats over and over. But it's just its own thing, with no external reason other than the explanation of what happened.
Turns out, people find this really hard to accept. I claimed that this is a simple answer, but in practice it opens up a lot of other questions. If the rock has no "why", does anything? How do we live without that? Is there any meaning to anything? Do our actions matter? This is not simple after all!
Or....
Ah, see, now this is easy. The main reason we have rock is so we don't fall through the earth. I mean, it could be something else solid — like, wood would work, but then, how would it get there? Or metal, but that seems like too much metal. So we've got rocks for that.
Maybe it's because the rocks like to do that. They feel good filling that purpose. I mean, not my rock. It's not holding anything up... it's kind of retired from that, and moved on to being an object of comfort and contemplation.
I can definitely see why, if there were some kind of creator beings, they would want to make rocks. Absolute basic stuff, in every sense.
It follows that there are equally satisfying answers to all those other questions about life, the universe, and everything. Nice! Tidy! Completely simple, really!
Maybe my "simple" explanations don't feel very simple. That's okay — there are probably a hundred other ones, too. I hope we can agree that the scientific-based ones are pretty complicated.
I am sure that we can agree that my terrible explanations are vast oversimplifications — really understanding the details of even a small part of any of that could be a lifetime's study, and still incomplete. And this is just about a rock.
So, back to what I left out at the beginning — "all things being equal", or other such careful caveats about "not requiring addition external explanations". I'm not at all convinced that it helps. What does it mean for things to be "equal"? It's so vague. And... every scientific answer definitely has another layer of complexity.
I'm back to Wikipedia for a second here, to bring up a strong form of the Razor, from Ernest Mach (as his "Principle of Economy"): "Scientists must use the simplest means of arriving at their results and exclude everything not perceived by the senses."
Well, with everything being equal, here at my desk, the scientific approach went beyond "perceived by the senses" almost instantly. Even with elaborate equipment and a lot of time, most of that would actually be from inference and reason based on observation, not direct perception.
Of course, so do any explanations (mine or otherwise) that go to theological answers rather than simply observing the direct phenomena: but, all things being equal, those seem to be pinnacles of parsimony in comparison to the scientific explanations. (Consider this important moment from classic-era The Simpsons.)
I think this answer to another question on the value of Occam's Razor overall really has something right. This is a useful rule of thumb with some subtle depth. But, it doesn't really provide any satisfaction when applied to the big questions. Maybe apparent-simplicity isn't a good metric for anything so important.
In principle... no. In practice... also no.
Because... Ockham's Razor is used to compare explanations... that are otherwise equal.
"God did it"... is not an explanation. It is a claim. God-->>poof-->>result.
"poof" is not an explanation.
Ockham's razor is not the theologian's friend.
Leaves no question as to "how" - Again, this sounds like you are aiming for a painfully exhaustive and detailed explanation that leaves no room for questions. This extraordinarily high standard would render abiogenesis and evolution as non-explanations, since they are replete with unknowns (especially abiogenesis).
– Mark
Feb 29 '24 at 21:45
The simplest explanation for where I came from is that God put a baby in my mommy's tummy. My father taught me about the birds and the bees, that's way more complicated, but I believe him. In school I learned more, about sperm and eggs, making it even more complicated, but I still believed it. I learned more, about DNA and genetics and that made it more complicated, but I still believe it.
As others have said, Occam's razor depends on your definitions of complexity and simplicity. I can't think of anything more complex than an all powerful being capable of "designing" and the magical powers to "create" all we see in the universe. The "simplicity" of a defining a deity is just a sham, hiding the complexity that must exist behind the curtain.
There is a quote attributed to Einstein that is relevent:
“Make everything as simple as possible, but not simpler.” Albert Einstein
If the goal of all explanations is the goal set forth by Einstein, then Occam's Razor naturally follows.
Sometimes, theism presents explanations that are too simple.
I am sceptical that Occam’s Razor will ever favor theism.
Because the God-entity of Christian theism has so many internal inconsistencies which hinder its rational use. The main inconsistency is the combination of the three properties being all-benign, omnipotent and omniscient.
The first condition, which is to be met by the God-concept and any other concept, is the internal consistency and the consistency with all other concepts of the given theory.
Aside: I am well aware that the OP’s post touches an issue which is controversially discussed on this platform and in the history of philosophy as a whole.
If all other criterions are the same, then no, it can’t favor theism. There is nothing more complex than an all knowing all powerful entity which we don’t even know can exist.
The rest of the answers suggesting that Ockham’s razor is merely a tool are missing the point. Everything in philosophy is a tool. We cannot decisively prove or disprove anything. But we need to be practical and assign plausibility criterions to differentiate between theories. One way to do this is using Occam’s razor.
In theory, demonstrate the impossibility of biogenesis on Earth; therefore Earth must have been seeded by life somehow or other. With this switch thrown you have three most plausible hypotheses:
Now Occam's razor makes theism vs naturalism a toss-up.
If all near solar stars through the back-tracing of the Sun through the Galaxy (a calculation we cannot do one way or the other at this time) are not suitable for biogenesis; then and only then does Occam's Razor directly favor theism, because 3 becomes implausible and 2 has a second entity requirement of superluminous travel.
Theism introduces unnecessary complexity into our explanations. If we can explain the origin and evolution of the universe through naturalistic processes, then the postulation of a deity who created the universe and intervenes in its operations might be seen as an unnecessary addition to our explanatory framework.
Also theism is not testable. For example, we can test naturalistic explanations through scientific observation and experimentation, while theistic explanations often rely on faith or personal revelation. In this sense, naturalism might be seen as a more reliable and empirically grounded explanatory framework than theism.
Also we shouldn't forget that "theism" is basically ideology for the church and church is one of the oldest tools of control. It's not actually a hypotheses. It's a social tool of manipulation. A very practical thing. :)
