Hypothetical: If we assume God does not exist, is theism unreasonable?

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Strictly for the sake of argument, let’s assume God does not exist.

Now, if someone believes something that turns out to be false, does that automatically make them irrational?

Think about the old Phlogiston theory. In 1750, it was the best explanation for why things burn and rust. Given the tools and knowledge they had at the time, scientists were completely rational to believe in it, even though we now know it was 100% false.

Now, you might immediately point out a big difference: Phlogiston was rational because it made testable predictions and was open to being proven wrong. Religious belief doesn’t seem to be testable in that same empirical, controlled way.

And that’s exactly the knot I want to get at. Is that kind of testability the only thing that makes a belief rational? Or can other features, like a web of philosophical reasoning, a coherent way the belief fits with the rest of your experience, and powerful personal experiences, count as rational support too, even when the claim can’t be settled by a lab experiment?

To keep the focus clear, I’ll sharpen the scenario. Imagine a theist who has spent years studying the best philosophical arguments, wrestling with objections, and reflecting on profound personal experiences. From their perspective, the reasons genuinely seem sufficient. I’m not asking you to agree that those reasons are ultimately sound. Given our assumption that God doesn’t exist, we already know the conclusion is false. My question is about the process that led them there.

So here’s my question: What counts as being rational?

Is it about how you arrived at your belief, based on the reasons and experiences you had along the way?

Or is it only about whether you turned out to be right in the end?

If that theist, after careful and honest reflection, believed, and it just so happens God isn’t real, was their thinking still rational?

Or does the fact that the claim can’t be tested in the usual empirical way make the belief irrational, no matter what is actually true, and no matter how seriously the person tried to reason well?

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Hello Aluneth :smiley:

I’ll try and do my best to answer your questions.

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Done.

Believing an untestable claim is irrational. How could a claim even be shown true or untrue if it can’t be tested? How could there be a way to show that a claim is wrong if it can’t be tested?

We may as well go ahead and disbelieve that claim until testability and sufficient evidence lead us to believe.

That was easy. I like easy.

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Something is irrational if it is not in accordance with the principles of logic. So if you present your best argument for the belief, we can see if it is rational. Bare in mind that you cannot argue something into existence, so we can only assess the arguments, the belief is another matter, but if the arguments that support an idea are weak or poorly reasoned, and the belief is unsupported by any objective evidence, why would you believe it?

Well no scientific idea can violate a principle of logic. So until we see your arguments for a deity, this might be a false equivalence. You also seem to be edging towards a form of Pascal’s wager.

Sadly I can’t make this assumption, even as an atheist, as a hypothetical I am not sure it adds much, why not just examine the best evidence and arguments available, that makes a lot more sense to me.

Well it cannot violate a principle of logic, that’s a given, beyond that is your reasoning subjective, how much effort are you making to remove as much subjective bias as is possible? That for me is the difference between a method like science, and religions which are entirely subjective, and at their core make unfalsifiable claims. Science tests idea critically and objectively, to try and falsify them, religions use faith to believe what they cannot evidence in any objective way. To me believing some unfalsifiable ideas, but not others is simply bias, this is closed minded by definition, believing them all is inevitably irrational as you’d have to violate the law of non-contradiction, disbelieving them all is perfectly rational and one can still be open minded.

  1. Define your deity, evidence your assertions
  2. Present the best arguments for your belief that deity exists.
  3. Demonstrate any objective evidence for that belief.

The horse comes first, then the cart…

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As far as scientific investigations go, the assumption that a god (or more specifically, a creator god) does not exist is by definition the null hypothesis, as that is the default assumption unless empirical evidence strongly supports other conclusions. Other hypotheses, such as the existence of this god (or a god), or that the concept of god/s is/are an emergent property of a sufficiently complex biological neural network (such as the homo sapiens brain) that seeks to make sense of the world it perceives through its sensors (eyes, ears, etc.). These can then be examined and tested.

But before we come to that stage, we really need to define what the god hypothesis encompasses. Therefore, what is your definition of “God”?

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Thanks again, I appreciate the thoughtful reply. :slightly_smiling_face: I’m trying to understand your distinction between “speculative” and “irrational” a bit better. Suppose someone engages with scientific findings and philosophical reasoning, and ends up thinking this raises the probability of a mind, call it God, having created the universe, even though the matter can’t be empirically settled. I’m not asking about whether that belief is true, only about the reasoning process itself. Would that still fall under “speculative” in your view, or would it cross into a faulty method? Just trying to see where the line falls.

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Thanks for asking me to define God, that’s fair. Let me offer a clear definition, and then I’ll respond to the broader question about evidence.

I think of God as a transcendent mind of immense power, not a physical object inside the observable universe. This mind is the reason there is anything at all, and it actively sustains all of physical reality: the motion of the sun, a pen writing on paper, the regular patterns we call natural laws. This mind can communicate with us, hear prayers, and relate to us personally. I don’t belong to any organised religion, and I’m not relying on scripture here.

You mentioned the importance of objective, testable evidence. I understand why that standard feels important, especially given the success of science. But I’ve often wondered: is it the only reasonable way to support a belief? That idea itself is a philosophical view, not something proven in a lab. I’m not dismissing the value of empirical evidence, I’m just curious whether we both might rely on some philosophical starting points that can’t be tested in a straightforward way. If so, that’s not a problem unique to my position; it might apply to the foundations of anyone’s worldview.

I raise this because sometimes religious experiences get dismissed as “just subjective,” while the claim that the brain alone produces consciousness gets treated as obvious. Yet when I look at the science, the evidence for that assumption seems thinner than many people assume. Take dreams, for example. The idea that dreaming is purely brain-generated is supported by a messy patchwork of indirect measures, not a decisive empirical demonstration. The tools we use, like fMRI, are noisy, have poor temporal resolution, and only pick up the slow blood-flow aftermath of neural activity, not the neural firing itself, so a lot of brain activity is simply missed. Add to that the stressful, unnatural conditions inside a scanner, and it’s not exactly ideal for capturing the richness of dream experience. Sample sizes are often very small compared to the trillions of dreams happening each year. And there’s an interesting gap: we have surprisingly few robust, repeatable studies showing that damage to a particular brain area reliably removes a specific sensory quality in dreams (say, the ability to smell anything no matter how hard you try). The neural correlates are messier than the neat “brain produces mind” story suggests.

Why does this matter? Because if the link between brain and consciousness isn’t as tidy as often presented, then the automatic dismissal of a vivid spiritual experience as “nothing but” brain activity might be less scientific than it appears. I’ve had experiences like this: an encounter with a divine presence that felt as real and perception-like as seeing this table in front of me. You might interpret that as a hallucination, and I respect that possibility. But that’s an interpretation, not a neutral fact, and it would need its own support. The experience itself exists, and it’s a widespread phenomenon across cultures and history. A worldview that rules it out in advance may be shielding itself from a whole category of human data.

Beyond experience, I also find a philosophical consideration compelling. The universe is made of contingent things, meaning things that don’t explain their own existence. I wonder whether it’s more rational to think that a necessary mind ultimately explains why anything exists at all, rather than treating the existence of everything as a brute, unexplained fact. The first option aims to complete the explanatory chain; the second stops the chain without a reason. I’m not presenting this as a knock-down proof, just a line of reasoning that seems philosophically serious, not a gap-filler for bad science.

So I’ve shared a definition, mentioned a kind of experience that seems hard to reduce, and offered a philosophical reflection. I’m genuinely interested in your view: if someone believes that only objective, testable evidence can support rational belief, can that standard be justified without going in a circle? If not, maybe we’re both working from philosophical commitments, and we can compare them openly. I’d like to do that honestly, with neither side treated as irrational by default.

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False equivalence, brains exist as an objective fact, human consciousness, exists as an objective fact, the deity you’re proposing has yet to be objectively evidenced at all, even your definition is imagined, that’s your own word.

Now even more of a problem, in every instance consciousness disappears at the precise moment a brain ceases to function, and just as problematic, human consciousness has never been observed in the absence of a functioning human brain. When that brain is impaired consciousness is impaired in direct correlation to the injury.

Now that is all objective evidence that supports the idea that human consciousness is an emergent property of a functioning brain. Again we have no objective evidence for any deity.

Can you evidence a single example of a dream being produced in the absence of a functioning human brain? This is the real kicker, lets say none of this were true, and we had no objective evidence that a brain was required for consciousness, this still doesn’t evidence any deity, at all.

There is a link, all we have for a deity so far are bare claims.

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We get this error in reasoning a lot, disbelief of a claim is not itself a claim, and it’s perfectly rational to disbelieve something, and still keep an open mind. All one need do is treat all ideas the same without bias for or against. The word dismissal is misleading.

You did, but the attributes are completely unevidenced of course.

Well there were what appear t be rational flaws in some of it, see above.

Take this for example, at the very least it is inaccurate and requires qualifying. The parts of the universe we currently observe and understand appear to be contingent. Now, more problematic is the fact we cannot rationally apply what we currently observe beyond the big bang, and the origin of that universe. Do you know what a hasty generalisation fallacy is?

So to be blunt, an unevidenced deity, that has no explanatory powers, creating a universe based n incomplete data.

Why a deity at all, if one can posit that much one can imagine just about anything.

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I got stuck with your initial description of your god. It is outside the observable universe but fully interacts with everything inside of it? What do you posit is the mechanism for this? How can something be both not inside and inside a place at the same time?

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I think there’s a subtle but important distinction that might help clarify where I’m coming from. I’m not trying to score points. I genuinely want to understand whether we’re using “evidence” in the same way.

1. Observation vs. inference

You said:

What we actually observe in those moments is the cessation of measurable brain activity and outward responsiveness. That’s an empirical fact, and I don’t dispute it. But the claim that subjective experience itself completely vanishes at that point isn’t itself an observation. It’s an inference. It relies on the assumption that consciousness is nothing over and above brain function, which is part of what’s at stake in this discussion.

I’m not saying the inference is unreasonable. I’m just noting that it’s a philosophical move, not a direct empirical reading. If we’re careful, we can separate the data from the interpretation.

The same applies to the correlation between brain impairment and mental changes. Correlation tells us the brain and mind are intimately connected, but it doesn’t, on its own, tell us whether the brain generates consciousness or whether it mediates it in some way. A damaged radio distorts the sound, but that doesn’t demonstrate the radio creates the music.

2. The dream point

I’m sorry if my earlier point about dreams was unclear. I wasn’t suggesting that dreams occur without a brain. I was pointing to a much narrower evidential gap: if the brain constructs every sensory quality from scratch, we might expect specific lesion studies to show, for example, that damage to the olfactory cortex reliably removes smell in dreams, much as it can in waking. The patchiness of that evidence is at least worth noting for a theory that says dreams are purely brain-generated. It’s not a disproof; it’s just an area where the data are less tidy than sometimes presented.

My only request is that we not treat “the brain produces all aspects of experience” as a settled empirical finding when parts of the picture remain inferential.

3. Why this matters for our discussion

I bring all this up not to sidetrack us into neuroscience, but because it connects directly to my original question about what makes a belief rational.

You’ve emphasised objective, testable evidence as the standard. I respect that. But the claims we’ve just looked at, about consciousness and dreams, are themselves supported partly by philosophical inferences that can’t be settled purely by a lab experiment. That doesn’t make them irrational. It just means that both our positions involve starting points that aren’t purely empirical.

If that’s the case, then maybe the line between “rational” and “irrational” isn’t simply “has been proven in a lab.” Perhaps it includes things like: coherence with the rest of what we know, explanatory completeness, and the weight of lived experience, provided we’re reasoning honestly about them.

You mentioned that I haven’t provided sufficient evidence for rationally believing in a deity. That’s exactly what I’m trying to examine. I’m asking whether the evidence a person can access through philosophical reflection, personal experience, and a sincere effort to make sense of the world can ever be sufficient for rational belief. Or does “rational” require a specific kind of evidence, testable in a lab, and if so, what justifies that requirement itself?

That brings us back to the original question. If we accept, for the sake of argument, that God does not exist, can a theist who carefully weighed philosophy, experience, and the arguments available still be considered rational in their belief? Or is their method itself insufficient, no matter how honestly it was applied? I’d be curious to hear how you define the threshold for rational belief, and whether that threshold can be justified without leaning on a philosophical commitment of its own.

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Think of a video game. The programmer isn’t a character inside the game world; he doesn’t occupy coordinates on its map. Yet he can make a tree spawn, change physics, display a message to a player, or sustain every running process, all without being located inside the space of the game. His causal power over that world doesn’t require him to be ‘in it’ as an object among objects.

Now, obviously a human programmer still lives in our physical world and uses hardware. That’s where the analogy intentionally stops. I’m not saying God uses a cosmic computer. The point is purely about causal relation without spatial location. If an intelligence can already sustain and interact with a whole environment without being inside it even in our limited human case, there’s no contradiction in a far greater mind doing the same for physical reality, without a physical medium, and without being part of the system it upholds.

God’s relationship to the universe is like that: not a physical object pushed out to some edge, but a non-spatial mind actively thinking the whole of reality into being, moment by moment. That’s how God can be the ground of every physical thing, sustain every interaction, and relate to us personally, without being ‘inside’ the system the way an object is. It’s not a contradiction; it’s a category difference between the thing that holds something in being and the thing being held. It’s not that God cannot enter the physical world nor that he doesn’t; it’s just that he doesn’t need to.

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That If is doing a lot of heavy lifting. I see no substantive evidence that you are basing your argument on anything other than imagination, wishful thinking, or assumptions.
You are positing something that is extraordinary. It will take, at least for me, a lot more than the vaporous pondering you have offered to substantiate it.

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I don’t know what you mean by “transcendent mind”. You need to define that.

In order to have an influence on the physical world and the universe, this god-creature must be able to interact with it. And that would have to be done through known or measurable interactions. So the effect should be measurable, thus in principle falsifiable. If this god is not a physical object, it would be pure radiation. If the god is “outside the observable universe”, it is by definition not observable, its interactions with the observable universe would be indistinguishable from natural processes, and thus not falsifiable. Thus, this is no good as a definition, as whenever you disagree, you can just point to your definition, shake your head, and say “nuh-uh!” In short, your “definition” is dysfunctional, an evasion, a cop out.

Here’s a definition that is equally valid: Eric the invisible rainbow-farting unicorn is the source of all happiness in the world. He ate the judeo-christian god for lunch one day in 945 BC and his digestion distilled the narcissism and vengefulness of YHWH into happy pixie dust, which makes out the rainbows. He lives in my garage, and chooses to only interact with people who believe in him.

Your “definition” was entirely predictable, and is not usable as a start for a discussion. Try again.

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On interaction and measurement

You said:

I’m not sure that’s as obvious as it sounds. It seems to assume all causation has to be physical, like an exchange of energy or forces inside the closed system of the universe. That’s a philosophical position (causal closure of the physical, I think it’s called), not something we’ve discovered empirically. Could you explain why you think this has to be true? If God were the sustaining ground of all existence, I mean really the thing holding everything in being, then the “interaction” wouldn’t need to be a separate signal within the system. It could just be the fact that the system exists at all. I’m not asking you to agree with that. I’m asking why the alternative is ruled out from the start.

Definitions and the unicorn thing

I gave a definition: a transcendent mind of immense power, the reason anything exists, actively sustaining reality. You came back with Eric the invisible rainbow-farting unicorn. Look, I get the point you’re making, but I don’t think these are actually on the same level. The concept I offered connects to a long history of philosophical thinking about contingency, existence, mind, and so on. It tries to explain something deep: why there’s anything rather than nothing. The unicorn doesn’t try to explain anything, it’s just an ad hoc cartoon. If you genuinely think they’re equally empty, I’d be curious why you think the philosophical arguments for a transcendent mind carry no more weight than a made-up creature. That seems like a pretty strong claim, and I’d be happy to hear your reasoning on it.

Back to the original question

I feel like the hypothetical I started with got a bit lost. I asked: if we assume God doesn’t exist, can a careful, honest theist still be rational in believing? The reason I asked that is because I’m trying to figure out what standards we’re using when we call someone rational or not. You’ve put a lot of weight on objective, testable evidence. I respect that. But I wonder if you think that’s the only way a belief can be rationally supported. Could things like philosophical coherence, trying to make sense of your whole experience, or the force of certain arguments also count, especially when the question isn’t the kind of thing a lab experiment could settle?

If your answer is that only empirically testable beliefs count as rational, then I’d like to push a bit: how do you justify that standard? Can you test it empirically? Because if not, then it’s a philosophical starting point too. And maybe both of us are bringing philosophical commitments to the table, and we could just compare them honestly.

A direct question to you

To try and avoid talking past each other: in your view, what exactly makes a belief rational? And can that criterion be defended without relying on some prior philosophical commitment? I’m genuinely curious, and I think answering this would clear up a lot of the back-and-forth.

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Well, that’s the rub, isn’t it, Aluneth?

If you engage with scientific thinking then aren’t you are obliged to begin with science’s remit? Which is that it is an agnostic system of thought that can say nothing about religious, spiritual or theological matters. Science’s remit is to investigate the natural universe and anything that falls outside of that remit - like a supernatural god - automatically falls outside of that remit.

Therefore, if you really are following the science methodology properly you should NOT use scientific evidence to conclude that there is a God. Science, when properly used does NOT allow you to draw that conclusion.

But if you have, then I would suggest that what you are doing is following. You use science to investigate the natural universe and then, by a personal and private act of faith, conclude that the evidence points to a God. Thus you are subverting an agnostic process that does not allow you to arrive at that conclusion.

So this two-stage process, with science at the start and then faith at the finish, begins rationally because that is what the methodology of science demands. The moment religious faith takes over from science is when the science arrives at the only agnostic conclusion that it can - that it can say nothing about a God. When this happens the person performing this process leaves rationality and reason behind and gives in to the demands of their emotions.

By definition human emotions are a law unto themselves and rationality is not a hallmark of their workings. If anything, irrationality is the hallmark of decisions made on an emotional basis. So, if a person decides that there is a God and has not done so on the rational basis of scientific evidence (because science can say nothing about God) they must be doing so on an irrational basis. Their emotions swaying their judgment and causing them to make a leap of faith that science alone cannot do.

Does that clarify things?

Thank you,

Walter.

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Thanks, that actually made your view a lot clearer. I’m still chewing on a few bits though, if you don’t mind.

1. The hypothetical you skipped

I think my original what‑if kind of got buried. I wasn’t asking how we’d ever prove God doesn’t exist. It was more like: just for the sake of the question, imagine God isn’t real. Could someone who looked at all the reasons honestly and ended up believing still be rational in how they got there? Or does a wrong conclusion automatically make the whole process irrational? You didn’t really touch that, and I get it’s a weird hypothetical, but I think it’s the bit I’m most stuck on. For me it’s not about whether God’s existence can be disproven, but about what we even mean by “rational”: the process or the result.

2. Where does the rule come from?

The other thing is the line you drew between science and emotion. You said once someone steps past science’s agnostic position, they leave rationality behind and it becomes emotional. I was trying to figure out where that rule itself sits. Is that rule a scientific finding? It feels more like a philosophical starting point. But if it is philosophical, then at least one non‑scientific step, adopting that rule, would count as rational for you. I’m not trying to catch you out, just trying to see how you’d describe the foundation of the whole thing. Because if the rule isn’t scientific, then “only scientific stuff is rational” seems to pull the rug out from under itself.

3. Where do philosophical arguments fit?

Also, you described a two‑step move: science, then emotional leap. The kind of believer I had in mind wasn’t really someone who just feels strongly after looking at science. It was someone who also digs into philosophical arguments, like why there’s something rather than nothing, or fine‑tuning, and tries to weigh them. I’m not sure where that fits in your picture. Would you file that under emotion too? I struggle myself to tell where reasoning stops and emotional rationalization begins, so I’m curious if you’ve got a clear way to separate them. Right now it feels like there’s a big chunk of thinking that just disappears in your description.

4. The galaxy problem

And one last thing. You said before that speculating about galaxies beyond what we can observe can still be rational, because it’s based on a kind of extrapolation. I’m just wondering why a philosophical guess about a cause of the universe wouldn’t get the same pass, if it’s built on something like “what best explains this?” Both go past what we can directly test. What’s the actual difference for you? I couldn’t quite pick it out from what you wrote. Maybe I’m missing something obvious, but it seems like if one kind of untestable inference is okay, the other shouldn’t be ruled out automatically just because it’s about God.

Anyway, those are just the bits I couldn’t smooth out. Really not trying to be difficult, just trying to get the picture clear.

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And yet this metaphysical brain has a sex?

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1. The hypothetical you skipped

I think my original what‑if kind of got buried. I wasn’t asking how we’d ever prove God doesn’t exist. It was more like: just for the sake of the question, imagine God isn’t real. Could someone who looked at all the reasons honestly and ended up believing still be rational in how they got there? Or does a wrong conclusion automatically make the whole process irrational? You didn’t really touch that, and I get it’s a weird hypothetical, but I think it’s the bit I’m most stuck on. For me it’s not about whether God’s existence can be disproven, but about what we even mean by “rational”: the process or the result.

Ah, but consider this Aluneth.

Of all the different branches of science, the only one that employs proofs is mathematics. All of the others are empirical sciences and as such they do not employ proofs. They make hypotheses and theories to the best explanation, given the evidence to hand.

Proofs are final and absolute and can never be overturned by new evidence. That is why a mathematical proof stands for all time. Whereas a scientific hypothesis, theory or model can always be overturned and refuted by new evidence. The findings of the empirical sciences are therefore always tentative and provisional, never final and absolute.

On that basis, I never said or even implied anything about proving God’s existence or non-existence using science. Because it can’t be done. As mentioned earlier, science is an agnostic system of thought on all matters religious, spiritual and theological.

That leaves logic (which does use proofs) and philosophy, which doesn’t. So are you asking me about proving the non-existence of God using logic? Because, as far as I can see, that’s the only viable way of doing it.

Thanks,

Walter.

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No, it’s not a finding. It’s part of the philosophical foundation of science. This link is helpful.

Karl Popper (Stanford Encyclopedia of Philosophy)

So, adopting this rule is rational.

Because it’s not based upon emotion but upon the pragmatic necessity for science to be as objective as possible. This requires that all scientists put their personal religious beliefs and their emotions to one side while practicing the discipline of science. What they believe and what they feel in the privacy of their own minds shouldn’t come into the scientific process at any stage.

So the rule isn’t scientific per se, having been derived from observations. But it is rational. For example, logic is not science, but it is rational. Therefore, all that is scientific should be rational but not everything that is rational must be scientific.

Does that help?