Ethical Realism

March 31, 2011

Arguments for Intuition

Philosophers often discuss what beliefs are intuitive or counterintuitive to support their conclusions. I will argue that we should prefer theories and beliefs that are intuitive or sensitive to our intuitions rather than ones that aren’t.1 The fact that a theory or belief is intuitive isn’t conclusive proof and a theory or belief being counterintuitive isn’t a conclusive refutation, but it is one important element when evaluating the plausibility of a theory or belief. Intuitive beliefs range from things we know with high degrees of confidence—such as “at least two people exist”—to beliefs that are merely plausible enough to take seriously as possibly true. When a theory isn’t intuitive, then we call it counterintuitive, absurd, or revisionistic. I will argue that, all else equal, we should prefer that our theories are intuitive rather than revisionistic for at least the following three reasons:

  1. Language has limits and ordinary discourse greatly determines how our language connects to our understanding of the world. An extremely revisionistic use of language can completely fail to communicate properly and can become off topic.
  2. We think we know things with high degrees of confidence without always being able to provide good arguments for those beliefs.
  3. We can’t provide an argument for everything. We have to have some assumptions.

I will (1) briefly discuss intuition, and (2) argue that we should prefer intuitive beliefs and theories.

1. What is intuition?

We say our beliefs are intuitive when we believe they are justified, but we have a hard time giving good arguments for them. In many cases intuition is likely our unconscious ability to attain knowledge. It isn’t when we have a hunch, it isn’t popular opinion, and it’s not a supernatural power. The problem with intuition is that we often refer to a belief or theory as being intuitive when we don’t think we can provide non-intuitive evidence in favor of that belief or theory.2 It’s hard for us to explain to others why we have certain beliefs despite our high degree of confidence. At that point we often hope they can agree how intuitive the belief or theory is.

An intuitive belief can be one that we think is strongly supported by an unconscious ability to attain justified beliefs, it can be necessary to explain our justified beliefs, or it can merely seem compatible with our justified beliefs. We have independent reason to accept beliefs in isolation when they are directly supported by intuition, but a belief that is merely compatible with our other justified beliefs is also more likely true than the alternatives (and might also be said to be intuitive).

We would prefer that a belief be justifiable without the use of intuition. It’s much more clear why we should believe something based on observation than intuition because intuition is—by definition—an unconscious form of justification that is difficult to explain in words. Intuitive beliefs are not necessarily impossible to justify through non-intuitive forms of evidence, such as observation. Sometimes we can propose such non-intuitive forms of evidence to provide an argument in favor of our intuitive beliefs.

Many people dismiss intuition as prejudice because it is used to argue in favor of certain beliefs without entirely satisfying evidence. However, intuition has proven to be quite reliable upon occasion and I think it’s too demanding to expect all of our beliefs to be proven (through non-intuitive evidence).

We have good reason to expect that many of our intuitive beliefs would be difficult to justify through arguments and non-intuitive evidence. What we think of as intuitive evidence is not incompatible with other forms of evidence. In fact, many (or all) of our intuitive beliefs are actually based on unconscious knowledge formation that is based on various forms of evidence. Such a knowledge formation process does not necessarily map onto a simple argument that’s easy to communicate to others. Instead, it can be based on very complected forms of reasoning, and they might even be based on forms of evidence that can defy our ability to communicate. Consider the following forms of intuitive justification that are not based on observation3:

a. Self-evidence

Self-evidence is a non-inferential form of evidence that doesn’t make use of arguments. Robert Audi argues that we grasp self-evident truths through sufficient maturity and contemplation. Self-evidence might not exist at all or it might only exist in the form of conceptual knowledge. We can know that some things are true by understanding concepts, like “2 > 1,” “1+1=2,” and “all bachelors are unmarried.” Self-evident beliefs are not necessarily obviously true. For example, we aren’t born knowing that “963/3 = 321” and it might not even be obvious to everyone. However, it is something we can figure out through time and by understanding the relevant concepts. Self-evidence, if it exists, isn’t always easy to describe because it isn’t a form of argumentative reasoning.

b. Instincts

What we understand or believe through instincts could be intuitive to us. Such intuitive beliefs would likely be a reproductive advantage in the majority of our existence, and could be advantageous because they beliefs are likely true in most circumstances. For example, children seem to recognize faces and understand some human psychology very quickly, and this understanding could very well be instinctive. If we know anything through instinct, then it’s not easy to defend through argumentation because it’s a product of our biology rather than a product of logical reasoning.

c. Introspective evidence

We experience our psychological states a certain way—our own thoughts, feelings, and experiences are not always easy to describe and how we know about them is not always easy to describe either. How a thought feels or what it’s like to have thoughts is difficult to describe and it might be that we lack the words necessary to explain it to others. For example, how can we explain what it’s like to see green to someone whose never seen it? It might be impossible to communicate such an experience to such a person. No matter what we say, we expect that they still won’t quite understand. Introspection could be taken to be a form of observation, but it’s about what it’s like for us to exist rather than what it’s like to perceive something with the five senses.

d. Coherence

Sometimes we can reason that something is probably true because it’s compatible with on our current justified beliefs and experiences, or because it must be true assuming our other justified beliefs are true. It can be hard to fully justify a belief through coherence because there could be thousands of justified beliefs and experiences involved. For example, our belief that the future laws of nature will be the same (or extremely similar) as those in the past is necessary for thousands or millions of our other justified beliefs to be true—that the sun will rise tomorrow, that we can pick things up with our hands two seconds from now, that we will have bodies an hour from now, that bread will be nutritious rather than poisonous a week from now, and so on. To fully justify that the future laws of nature will be like those of the past through a coherence-based argument would take way too long.

e. Common sense

My definition of common sense justification is that we can provisionally assume a belief is true until we have more reason to reject it than accept it. This is the justification we use when we have a working hypothesis—which is mainly what scientific theories rely on. A belief need not have any independent evidence to accept it, but it can still be reasonable to assume it’s true as long as the belief seems successful. Our assumption that the future laws of physics will be similar to those that exist now could ultimately require being a common sense assumption because it might be a justified assumption even before we attain a coherence justification in its favor. What we assume to be true through common sense justification is often difficult to formulate into an argument because the assumption has been successful (in part because there are no good objections against it). It can be difficult to list every single way that it’s been successful. There might be thousands of ways that a belief has been successful.

2. Arguments to prefer intuition to revisionism

a. Intuition is sensitive to language

Proper use of language is based on our intuitive use of language, and language has philosophical implications. For example, when I say that I know that I have hands, I am (in part) proving that I know what the word ‘know’ means to competent users of the English language. Anyone who argues that I don’t know that I have hands would seem to simply not know what know means or what hands are. We learn language in a great part by examples. People who learn what know means understands to tell others that they know they have hands and giving the wrong answer will be a great cause for concern. Sometimes our use of the word ‘know’ is very important, such as when a police officer asks you if you know who the killer is. It would be inappropriate to say, “It’s impossible to know who killers are.” That would be a total failure of communication and perhaps a failure to even understand the police officer’s question. She wants you to answer in a certain way and you should understand that.

Philosophers who ask interesting questions like, “When is knowledge possible?” will often define what ‘knowledge’ means, but that definition should be somewhat intuitive rather than radically revisionary. It should be sensitive to common examples of knowledge and how we use the word in everyday contexts. To prove knowledge is always impossible would require a radically revisionary definition of knowledge because the definition of knowledge is (in part) how we actually use the word in ordinary discourse including the examples we give of it. If a philosopher “proves that knowledge is impossible,” then we will think that philosopher doesn’t even know what the word means. The philosopher better tell the police officer who the killer is as an eye witness and not claim that eye-witnesses can’t possibly exist.

Also consider that water is H2O by definition. We had an ordinary definition of water at one point based on how we use the word in everyday life by referring to the stuff that rains, is found in streams, is necessary to quench thirst, freezes at the North Pole, can be easily boiled using fire, and so on. We had to discover that H2O is water by investigating the stuff involved when we use the word ‘water.’ If a philosopher at some point gave a revisionary definition of water as oxygen based on the fact that oxygen is found whenever we point to water, then we would think that the philosopher completely misses the point. Oxygen isn’t going to quench our thirst or freeze near the North Pole.

Finally, consider how language has implications for the word ‘morality.’ We can’t say that “killing people indiscriminately is always right” because what is considered to be right and wrong is defined (in part) through examples and one example of wrong behavior is killing people indiscriminately. Anyone who claims it’s not wrong wouldn’t know what “killing people indiscriminately” or ‘wrong’ means—or they are using an extremely revisionary meaning for ‘wrong’ that seems to totally miss the point. We could argue that they aren’t really discussing morality at all and they are actually talking about something else that is unrelated.

b. We think we know things even when we can’t argue for them

Perhaps the best reason to believe in intuitive beliefs is simply because it’s intuitive to do so. Once we realize that we already accept uncontroversial examples of intuitive justification, we will understand why we have good reason to believe in intuitive beliefs and make use of intuitive justification. Consider the following examples:

2+2=4 – I don’t know how to prove simple mathematical facts through argumentation, but I think I know they are true. I suspect other people are like me in that regard. We have a high degree of confidence that “2+2=4” and will likely think that any argument used to prove “2+2=4” will require premises that are less justified than the conclusion is anyway. People who argue that “2+2=4” is false or an unjustified belief are saying something striking that we would find absurd.

I know that I have two hands – I think I know that I have two hands even though I could be in a dream world, and I have a high degree of confidence about it. I can’t prove with absolute certainty that my observation of my hands is reliable or that I’m not in a dream world, but I think think that both of these beliefs are very likely true. I suspect other people are like me in this regard. People who say that they don’t know they have hands are saying something striking that we would find absurd.

It’s wrong to kill people indiscriminately – I think people know that it’s wrong to kill people indiscriminately, even though many such people don’t know how to explain how they could know such a thing. Any such explanation is also likely going to be less justified than the conclusion. Perhaps people or their experiences have intrinsic value and that value is lost when we kill them. That’s one possible explanation as to why it’s generally wrong to kill people. Even so, not everyone would agree with that explanation and there are others. It’s not obvious whose explanation is right or if they are all wrong. Nonetheless, I think most people know that it’s wrong to kill people indiscriminately with a high degree of certainty and any argument we come up with to prove it will likely require premises that are less justified than the conclusion they are meant to support. Again, people who argue that it’s not wrong to kill people indiscriminately are saying something striking that seems absurd.

An objection:

Isn’t it circular reasoning to justify intuition by saying it’s intuitive? Someone could argue that my argument here is that “intuition is intuitive, therefore intuition is relatively reliable.” That argument is viciously circular. We would have to assume that intuition is reliable to prove it is.

My replies:

First, we use intuition precisely when it is difficult or impossible to prove our justified beliefs through argumentation. Circular reasoning is a faulty form of proof through argumentation. I don’t claim that my argument proves that intuition is reliable, but I think it points out that we can have a reason to think intuition is reliable. If I thought I could prove that intuition is reliable because it’s intuitive to think it is, then my argument would certainly be viciously circular.

Second, my argument is based on practical considerations—we have no choice but to use intuition for our arguments because we can’t prove everything in arguments. I develop this line of reasoning in more detail below.

Third, it’s not always clear what kind of justification is at work when we use intuition. It’s possible to justify one form of intuition with another. For example, I think some beliefs are justified just because they are successful assumptions and others are justified because they are coherent with other justified beliefs. The idea that some beliefs are justified for being successful assumptions is supported if we know that the belief that “we can use the past to learn about the future” itself is both justified and can only be justified as a successful assumption. In that case we can justify the use of common sense justification (successful assumptions) through a coherence justification.

Fourth, if intuition is justified through successful common sense assumptions (which could be experienced as a form of intuition), then the belief that “intuition is reliable” itself can be one of our successful assumptions. The belief that some justified beliefs are justified because they are successful assumptions might not need to be proven through argumentation because it might also be justified for being a successful assumption. That’s not a circular argument because no argument would actually be required.

c. We can’t provide an argument for everything

Even if any true belief can be justified by an argument in principle, that doesn’t mean it’s possible to actually provide an argument for every true belief. That would take forever. For every belief, we will provide an argument (with at least one premise), and every argument requires us to accept at least one other belief that will also need an argument, and so on. To think that a real flesh and blood person is even capable of providing infinite arguments to justify a belief seems absurd because it would require infinite knowledge that makes the person capable of answering infinite questions. There are at least three ways we can avoid this problem:

  1. We can justify our non-self-evident beliefs through self-evident beliefs that don’t need to be justified through argumentation.
  2. We can justify our beliefs through coherence—including coherence with our observations and experiences.
  3. We can justify our beliefs through successful assumptions. Such assumptions should be capable of positive and negative qualities that can compete with alternative beliefs, so that a belief can be rejected (unsuccessful) at some point. Some people would say that the belief should be capable of falsification, but that might be a strong word for what I am considering. (This is what I call “common sense justification.”)

What does all this have to do with intuition? First, intuition is used as a practical way to avoid arguing forever. We can take certain beliefs as intuitive and therefore justified until we have overriding reason to reject them.

Second, I don’t think every single belief can necessarily be justified through observation, coherence, or self-evidence; so I find it plausible that at least some justified beliefs are successful assumptions, which we often experience as being intuitive beliefs. Additionally, I think there are good examples of assumptions that are justified despite being in need of no argument—such as the assumption that “we can use the past to learn about the future,” and that assumption in particular does not seem to be self-evident or provable through observation. It might be partially justified through coherence, but I think the belief is justified prior to coherence because it should be an assumption we use in order to form all the beliefs it is coherent with in the first place—that bread will be nutritious in the future, that the sun will rise tomorrow, and so on.


Many people are dismissive of intuition and act like it’s too mysterious to take seriously. They want an argument for every belief and they want non-intuitive forms of justification. I agree that it’s preferable to have non-intuitive forms of justification, but that doesn’t mean intuitive beliefs are worthless prejudice. People who demand that we justify every belief through nonintuitive argumentation are too demanding and their world would be a strange one where there’s an argument for everything. That’s not a realistic way to live life. Many of our beliefs are based on an unconscious ability to attain knowledge and transforming that unconscious process into arguments is not always feasible.

I agree that intuition is fallible, but it’s still worth something. All else equal, an intuitive belief is more justified than a counterintuitive one.

(Updated 11/25/2013)


1 If a belief or theory is sensitive to our intuitions, then we can call it ‘intuitive.’ An intuitive theory or belief can be supported independently by our intuition—unconscious ability to attain knowledge—or it can merely be compatible with other beliefs, experiences, and knowledge. I will often discuss ‘theories’ rather than ‘beliefs and theories’ merely for the sake of brevity.

2 Perhaps the most common example of non-intuitive evidence is observation.

3 Observation tends to be pretty easy for us to communicate to others, but what we observe to be true can certainly be “intuitive” and need not be known through argumentation.

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