The Appeal to Intuition: A Fallacy?

You might be familiar with what philosophers call an “appeal to nature“. It is a claim that something is good or right because it’s natural. Sometimes an appeal to nature is a fallacy. In this post, I discuss the possibility that an appeal to intuition is that kind of fallacy.

1.  Different Brain, Different Intuition

First, imagine that your brain and my brain are radically different from one another. If this were the case, then it would be unsurprising to find that your intuitions were different than mine. Indeed, evidence suggests that even minor differences between brains are linked to differences in intuition (Amodio et al 2007Kanai et al 2011).

This implies that our appeals to intuition (etc.) might be contingent upon brains being a certain way. In other words, differences in intuitions seem to be the result of differences in natural properties.†

2.  The Appeal To Nature

It is not difficult to find an appeal to intuition in philosophy. For example,

The idea that [P] is so intuitive that most will need no more proof than its statement (Wenar 2008, 10).

But what is going on when philosophers appeal to intuition? What makes something intuitive? Does intuition track truth or reliability or something like that? Or does it track something else?

If it tracks something other than truth or reliability, then our intuitions will change even if the truth or reliability does not. But, like I mentioned last week, some of our intuitions seem to change when our brains change. And changing our brains doesn’t seem to change what is true or reliable. So some of our intuitions do not necessarily track truth or reliability. They seem to track something else — something about the nature of our brains.

So widespread moral intuitions might not track truth. They might only track features of our brains. For instance, most people have an intuition that it is bad to harm people when the harm can be avoided. But if this intuition is merely the result of our having certain neural properties, then it is not clear that the intuition is true. Just because the intuition is widely shared doesn’t mean it’s correct. After all, if we changed everyone’s brains in a certain way, then maybe we would change our intuitions about harm (Crockett et al 2010; Crockett et al 2016).

3.  Explanation ≠ Justification

While natural properties can help us explain our intuitions, they do not justify them.†† This becomes more clear when we consider counterintuitive claims.

Some people try to show that utilitarianism is counterintuitive by pointing out that psychopaths are more likely to make utilitarian judgments (Bartels and Pizarro 2011).††† But it’s not clear how that amounts to an argument against utilitarianism. After all, the difference between our moral intuitions and a psychopath’s moral intuitions might be just a difference in brains (Glenn et al 2009, see also a response from Koenigs et al). So contrasting our intuitions with psychopaths’ intuitions ends up looking a bit like an appeal to nature. It appeals to the nature of neurotypical brains.


“Not so fast!” you might say. “Why should we think that the difference between me and a psychopaths’ intuitions is only a difference in brains? There are other differences. Namely, there are arguments that undermine psychopaths’ intuitions more than my intuitions” (this kind of response can be found in Deutsch 2015).

There are a couple claims here so let’s take them one at a time.


First, a concession. Neuroscience is far from fully explaining the differences in our intuitions. So it wouldn’t be surprising if there is more to our intuitions than what neuroscience tells us. Also, it’s not even clear that neuroscience can fully explain our intuitions.

Second, let’s think about those arguments against the psychopaths’ intuitions. What makes these arguments compelling? Is it similar to what makes something intuitive? What if the appeal of arguments — like intuition — can be explained by natural properties of our brains? If this is the case, then the mere existence of compelling arguments for an intuition doesn’t necessarily justify the intuition. It might only provide a post hoc rationalization of the intuition (Schwitzgebel and Ellis 2016).


It’s not obvious why one set of intuitions are supposed to be better than another set. Science reveals only that certain brains (normal brains, philosophers’ brains, etc.) produce certain intuitions (Kahane et al 2012). But that does not necessarily justify intuition. And it doesn’t debunk intuition either.

4.  So Is An Appeal To Intuition A Fallacy?

It seems pretty clear that our intuitions can depend on nature — e.g., on our brains being a certain way. So an appeal to intuition can be an appeal to nature. And an appeal to nature can be a fallacy. But that’s not enough to conclude that every appeal to intuition is a fallacy.

So the short answer to our question is this: not necessarily.

Longer answers will fall into at least three categories

  1. The necessary justification category: “No. Intuitions are justified because they are intuitions (and not because they are ubiquitous, reliable, useful, etc.). That is intuitions are — necessarily — justified.”
  2. The contingent justification category: “No. Intuitions are justified because of some accidental feature of intuitions (e.g., their ubiquity, reliability, utility, etc.). So intuitions can be justified, but they aren’t necessarily justified.”
  3. The unjustified category. “Yes. An appeal to intuition is a fallacy because intuitions are not justified. They are only apparently justified. But when we study intuitions, we find that intuitions are the result of natural (neural) properties — nothing more.”

I haven’t argued for any of these answers. I have merely tried to show that it’s not obvious how our intuitions can be justified. So you might wonder how you can argue for some of these answers.

5.  The Self-Defeat Argument

The Self-Defeat Argument might be the easiest way to argue that intuitions can be justified. It’s pretty simple. The most important premise is this: if intuitions aren’t justified, then nothing is justified (Huemer 2001, 107-8). The full argument goes like this:

…the rejection of [intuition] is self-defeating, roughly, because one who rejected [intuition] would inevitably do so on the basis of [intuition]. […] Therefore, if this opponent of [intuition] were right, his [rejection of intuition] would itself be unjustified. (Huemer 2007, 39)

Sounds intuitive, right? 🥁💥

Well, before you get too comfortable with the Self-Defeat Argument, you should know that some philosophers don’t buy it (DePoe 2011; Mizrahi 2014). So if you want to accept the Self-Defeat Argument, then you might want to see how you can respond to those philosophers (Huemer 2011; Huemer 2014). And then you might want to see a counter-response (Mizrahi 2014).

Closing Thoughts

So what do you think? Are intuitions justified? How? Why? How can science help us answer that question?

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† Notice that I did not say “only the result of natural properties.”

†† Notice how I didn’t say “fully explain our intuitions”.

††† I’m not saying that Bartels & Pizzaro do this. I’m saying that people appeal to Bartels & Pizzaro’s study to do this. Ibid.

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Nick Byrd

Nick is a cognitive scientist at Florida State University studying reasoning, wellbeing, and willpower. Check out his blog at

5 thoughts on “The Appeal to Intuition: A Fallacy?”

  1. I think you’re onto somethings that parallels what I’ve been thinking about recently.

    Let’s, for the length of this comment, reverse things a bit. Suppose that the brain is instead built from from intuitions. That from the beginning of our lives as human beings, we each have different kinds of intuitions that influences how each of our brains gets structured and built around. Because really, what are intuitions? I believe they’re the intersection between all the information our brain processes that somehow makes enough “sense” for the subconscious to pass onto the conscious without the ability to transfer the vast of information required to “build” that intuition. I hope I’m making some sense so far. How do we perceive? Through senses. The five senses myth already being debunked, senses allow us to perceive the physical world and many others we cannot touch. Among others, emotions, conceptualization and symbolism are all intangible parts of our reality that create together: languages and the bases for society that we all can feel. They are all as real as the world we can touch. Imagine every human being somehow more “in tune” with a certain group of senses and the different kinds of intuitions it might create. It doesn’t make intuitions any more reliable than your theory, but it sounds more intuitive to me. Lol.

    1. Hi Paper,

      There is a lot in that comment. I’ll try to take a few smaller bites rather than go for the whole thing all at once.

      A. The reversal idea is interesting: if we accept that the causal arrow goes the other way (from intuition to brain), then this might change things. But its hard to see how that is what is going on in the studies I mention above (e.g., Crockett). In those studies, experimenters manipulate something about in the brain and then a change in judgment occurs. So the direction of causation seems to be pretty clear. It goes from brain to judgment.

      B. I’m not sure I understand what is supposed to follow from this reversal. For example, I don’t know what you mean by ‘intersection” in “intuitions are the intersection between all the information our brain processes.” And I’m not sure what ‘makes enough sense for the subconscious to pass not the conscious’ means in the rest of the sentence. And I’m not sure what being being “in tune” with senses and their resulting intuitions would mean.

      C. I’m not sure I comprehend the discussion of the senses. How have the senses been debunked? How do senses perceive “other [worlds] we cannot touch?” What kind of worlds?

      Feel free to clarify. If I understand it, I might also find it intuitive. 🙂

      And thanks for commenting! I wish you well!

  2. Thank you for the excellent survey of this interesting topic, and for the bibliography you provided. My personal view on intuitions has always been this one: we must, for practical reasons, stop the chain of justification at some point. Intuitions can play this role, and we have the right to consider them to be provisionally true until someone proves otherwise, and replaces the contested intuitions with new ones. And so on, ad infinitum. Intuitions are only there for practical reasons, and should be taken only as provisionally true. This is similar to the self-defeating argument, so I will enjoy reading what philosophers have to say about it. Cheers!

    1. This is rather similar to Huemer’s view. So I think you’d like what Huemer has to to say about this. The Huemer 2007 paper is a good place to start. If you want more, then Huemer’s 2001 book is very good.

      Thanks for sharing! I wish you well!

  3. Hi Nick,

    It’s an interesting argument, but I’d like to raise a couple of objections.

    What about epistemic intuitions?
    For example, let’s say Bob is a Young Earth Creationist (YEC), but he is consistent. Since theory is (at least nearly always, and definitely when it’s about empirical matters) underdetermined by evidence, he consistently believes that YEC is true. He accepts all of the observations made by scientists, but interprets them as Lucifer planting fossils to tempt us, or Yahweh doing so to test us, etc.
    Now, imagine that his brain is wired radically different from yours, and he’s just assessing the evidence by his own epistemic intuitions (if you don’t call that “intuition”, my point would be he’s still doing it by whatever means his brain/mind does it). So, that explains his different intuitions. But intuitions can be wrong, and appeals to epistemic intuitions might be contingent upon brains being in a certain way. And epistemic assessments that do not use the word “intuition” might be also contingent upon brains being in a certain way, etc.
    My question would be: if the line of argument you raise against appeal to intuitions in the case of morality is successful, why is it not successful in the case of epistemic intuitions? Why would be the relevant difference?
    How can we even know moral truths?
    After all, it seems that we only have our sense of right and wrong to tell right from wrong, or some general theories, like utilitarianism in some form or another, or Christianity in some form or another, etc. But the general theories – as long as they do make predictions – can be tested only against our sense of right and wrong. I would say a proper way to test them is to consider hypothetical scenarios in which our sense of right and wrong delivers clear verdicts, and see whether the theory we’re testing matches the assessment. But is our sense of right and wrong different from our moral intuitions? What else is there? Perhaps, it’s partially a matter of terminology. What counts as an “intuition”? But it seems to me that considering hypothetical scenarios to see what our sense of right and wrong says is a test of the theory vs. our intuitions, in any way one can construct it.
    Moreover, if our brain were wired very differently (depending on how it’s wired), it’s pretty clear our sense of right and wrong (whether that’s what one calls “intuitions” or not) would deliver very different verdicts, or perhaps – if radically different enough, like some sort of alien -, it would not be a sense of right and wrong but some alien analog.
    What about color vision?
    If our brain is rewired in some ways, we could see colors very differently (that’s pretty clear; e.g., by the fact that nonhuman animals see colors very differently, or rather, they see species-specific analogues to color). Or we wouldn’t perceive color at all, but some analogue. But in any case, there would be a radical change too.
    In fact, there are people who do see colors differently, e.g., anomalous trichromats. Why is their color vision not reliable in tracking colors, and ours is reliable?
    (whether the difference is a difference in brains or in eyes does not make a difference to the argument, given the analogy with the appeal to nature).

    Granted, maybe these replies are similar to a “self-defeat” argument, but I’m not using Huemer’s general line of argumentation, but narrowing it down to specific cases and making parallels.

Thoughts? Questions? Suggestions?