A defense of philosophical intuitions

Be ye not afraid

Intuitions are used in philosophy as evidence. I’m here to explain the role that they play in epistemology and why intuitions are far more innocuous than some seem to think. This piece will be a bit of metaphilosophy, so if it’s a little too “inside baseball,”feel free to revisit one of my earlier bangers instead!

Too often criticisms of intuition sound like this exchange:

Philo: You are reading this sentence right now, and you grasp its meaning. You understand what the words are, how they are assembled, and as I tell you this you recognize that the previous sentence is true (or was a moment ago) and now this sentence is true. Reading, grasping, understanding, and truth recognition are all kinds of mental abilities or faculties.

Skepticus: Do you have a full psychological analysis of each of these concepts along with the truth conditions for their correct application? No? Well, I guess they are just made-up armchair fantasies invented by empirically-resistant philosophers. Get back to me when you learn some social science and how to run SPSS. Until then I don’t want to hear this nonsense about you reading sentences and understanding them.

I’m hoping we can raise the bar beyond the obnoxious Skepticus. There are better criticisms of intuitions I’ll consider (and reject), but first let’s think about mental faculties more broadly.

Mental faculties

There are lots of quite different kinds of mental faculties. Some of them have obvious failure modes, others can go wrong in weird ways, and for a few it is shocking to learn that other people lack them. All of them are scalar: they come in degrees. Here are some examples.

• Sensations: Smell, taste, touch, sight, hearing.

Lacking sensations is the most familiar psychological loss. People can be deaf or blind, they can lose their sense of taste or smell. This is familiar and routine. It can go the other way too. There’s such a thing as tetrachromatic mutation, in which women have four kinds of color receptors in their eyes instead of the usual three.¹ In comparison with tetrachromats, we trichromatic normies are 100 times inferior with our puny color vision.

• Memory: the recollection of past events and facts

Loss of memory is familiar to us all. We forget things. Some people forget things on a spectacular scale, from routine Alzheimer’s patients to famous amnesiacs like Clive Wearing. Others, like mnemonists, those with hyperthymesia, and savants, forget almost nothing.

• Emotions. Happiness, sadness, anger, fear, surprise, disgust, love, anxiety, jealousy, pride, empathy, etc.

Lacking all emotion does not seem possible, although people with flat affect have their emotions tamped down or blunted and others with alexithymia (emotional blindness) struggle to identify their own emotions. However, it is possible to not have specific emotions: for example, psychopaths lack empathy and those with anhedonia (anhedoniacs?) do not experience happiness.

• Nociception. The ability to feel pain.

A failure to have nociception is an extremely terrible condition. At first it may sound like a utilitarian’s dream to not experience pain, but it doesn’t take much reflection to realize that occasionally feeling pain is what’s keeping you alive. If you can’t feel heat, cold, or pain, then your body could catastrophically fail and you would have no idea. You could freeze to death and never feel a thing.

• Proprioception. Your internal psychological mapping of the location and activities of your body parts, and the recognition that certain physical objects are in fact parts of your body.

The Penfield map of the brain

When proprioception gets wonky, all kinds of bizarre things can result. Oliver Sacks wrote of a patient whose brain stopped mapping his own left leg as a part of his body. The patient was convinced that the “leg” near his torso was alien, a cadaver leg slipped into his hospital bed, some kind of monstrous joke or trick. Whatever it was, it couldn’t be his left leg. But when he very reasonably threw it out of his bed, the patient was astonished to find the rest of himself on the floor as well.

Then there are cases of extending proprioception so that the brain’s decided that non-body parts are really body parts after all. In a famous experiment, psychologists sat subjects down with their left arms resting on a small table. They hid the arm from the subject’s view with a screen, and put a realistic-looking rubber left arm and hand on the table in front of the subject. As the subject stared at the rubber hand, the experimenters used paintbrushes to simultaneously stroke the backs of both the subject’s real left hand (hidden from view) and the rubber left hand (in plain sight). After a few minutes, the subjects reported feeling the touch of the viewed brush, not the hidden one; their bodily proprioception reached out to incorporate the rubber hand into their own body image. The brain tries to synthesize and make sense of the taps and strokes that it sees and the ones that it feels, and after a bit the brains of the test subjects concluded that the rubber hand must be part of their body. They felt the rubber hand as being their own.

V.S. Ramachandran took this even further and had subjects watch an experimenter stroke and tap the back of plastic mannequin head with one hand while stroking and tapping the back of the subject’s own head in perfect synchrony. In no time the naïve subjects started experiencing the sensations as coming from the mannequin’s head instead of their own. One subject even said it was like being decapitated!

• Theory of mind. The spontaneous and automatic attribution of mental states to others, the interpretation of the words and actions of others as the result of intention, specific emotions, and beliefs.

For a long time, the most prominent theory of autism was that autistics lack a theory of mind and struggle with the automatic attribution of mental states to others. I gather that the mindblindness approach has since been challenged, although there does not appear to be a unified replacement paradigm. Theories of mind can also suffer from false positives, where people wind up with animism and believe trees have minds.

• Mental imagery. The ability to have mental images in the mind’s-eye, pseudo-perceptions of objects that are not actually being perceived.

People with aphantasia cannot form images in their minds. If you ask them to imagine an apple, they will say they are, but if you follow up by asking the color of the apple they have no idea. They did not form an image of an apple so much as reflect upon the concept of one. Aphantastics are just as amazed to learn that most people can form mental images:

I have never visualized anything in my entire life. I can’t ‘see’ my father’s face or a bouncing blue ball, my childhood bedroom or the run I went on ten minutes ago. I thought ‘counting sheep’ was a metaphor. I’m 30 years old and I never knew a human could do any of this. Source.

Hollis Robbins writes, “I have total aphantasia. I learned about it a few years ago and as a poet and poetry scholar I was dumbstruck. I had never understood the concept of “imagery”— I thought it was a metaphor. So to learn that people actually had a mind’s eye!!!”

• Mental language. Having words in one’s mind, thinking in words and sentences. Some describe it as having an internal narrator, or having two voices debating in one’s head. A mental monologue or dialogue.

You may be surprised to learn (as I was when I first heard of it) about anendophasia: the failure to have language in one’s mind. The thoughts of these people take linguistic form for the first time only when they are exiting their mouths. They learn about what they are saying in the act of saying it. One woman describes her thoughts as information files; she never daydreams, and her nighttime dreams have no words. Then there are people with both aphantasia and anendophasia! I guess they have a shortcut to Zen.

I’ve calmed my thoughts all right. Easy-peasy.

There’s vast cornucopia of mental faculties, they typically come in degrees (more color vision and less, more mental imagery and less, more emotions and fewer), some are unexpected or lesser known, and not everyone has every kind. Some of these have only been recently noticed by psychology (e.g. anendophasia, hyperthymesia) and are little studied or understood. I don’t think I’ve said anything terribly controversial so far.

The basis of knowledge

This shouldn’t be controversial either:

1. All the mental states discussed above are used as reasons, as evidence, to believe things. They are all sources of knowledge.

2. They are all fallible and can be wrong or misleading.

I think it is a windy day outside because I see it. I believe there are birds in the trees because I hear them. Where would science be without the testimony of our senses? Or take memory—if you remember that you parked your car in the parking lot near the bank, that’s a reason to believe that your car is in the parking lot near the bank. If nociception is telling you that your lower back hurts, that’s a reason to think that you’ve injured it, or something has gone wrong. When proprioception is informing you that your feet are up on the coffee table, that’s a reason to think they are not behind your head. The idea that mental states constitute evidence for beliefs is routine.

All those faculties of the mind can go wrong. Could our perceptions be mistaken? Of course. A straight stick in half in water looks bent even though it really isn’t. We often misremember things and even accurate memories still don’t guarantee the truth. Remembering where I parked my car doesn’t ensure it’s there; it could have been stolen. It turns out that rubber hand wasn’t a part of my body although it weirdly felt that way for a couple of minutes.

This is why we come up with theories of how the world works that sometime override the testimony of our perceptions, memories, etc. We’re looking for agreement from our different sources of evidence and if we don’t get it we dismiss the outliers. A good theory will explain how and why our faculties get things wrong when they do, e.g. why that stick looks bent in the water.

Maybe you want to insist that if a source of beliefs might be wrong then it can never be trusted. Lie to me once and I’ll never believe you again. Well, welcome to radical skepticism: no one knows anything at all.² Not a very popular view any more.

They will never get to common knowledge

Finally getting to intuitions

Intuitions are another kind of mental faculty. Evidently some people do not have them, like Lance S. Bush, who writes,

The use of the term “intuition” serves only to obscure matters in philosophy. Philosophers should collectively agree to stop using the term. I haven’t been the best at explaining what the problem is, but I don’t think I’ve butchered it, either. Nevertheless I’ve been discouraged and annoyed at the resistance. Why are people so fucking taken in by talk of intuitions? It’s like everyone slapped on one of those brain slugs from Futurama.

Bush is a man, blind from birth, angrily denying that others have a power he lacks and cannot imagine.

At the other end of the spectrum is the testimony of Saul Kripke: “Some philosophers think that something’s having intuitive content is very inconclusive evidence in favor of it. I think it is very heavy evidence in favor of anything, myself. I don’t know, in a way, what more conclusive evidence one can have about anything, ultimately speaking.”³ Plenty of other prominent philosophers agree, like Ernest Sosa, George Bealer, Robert Audi, etc. I’m not appealing to their authority here, just pointing out that using intuition as evidential is a mainstream (albeit not universal) view.

So what is intuition supposed to be? Rational intuitions are a spontaneous, rapid psychological assessment of truth and prompting to judgment about a priori propositions.

• 5+7=12

• It is wrong to torture puppies for fun.

• If you know something, then you believe it.

• Nothing can be both true and false at the same time in the same way.

• Cycling implies cyclists.

• Everything obligatory is also permissible.

• Impossible things never happen.

Once you understood the meanings of those sentences, did you say to yourself, “I dunno… I’m going to need an argument here”? Edgelords aside, I’m going to say no. You didn’t. You read those sentences and immediately agreed, or, minimally, were strongly tempted to agree. That’s rational intuition in action.

Where do these intuitions come from? That’s like asking “where do these perceptions come from?” Or “where do these emotions come from?” The obvious answer is that we evolved to have them. I give a thumbnail sketch of how moral intuitions could arise here.

You might be tempted to try an evolutionary debunking argument, like “so we’ve evolved to have certain intuitions. Big deal. Evolution doesn’t care about putting us in contact with the truth, only about propagating genes to the next generation. There no reason to take intuitions as evidence because there’s no reason to think they have anything to do with the truth as all.”

My response to the debunking argument is this: it leads directly to radical skepticism. Replace “intuition” with “perception” in the preceding paragraph and you’ll see what I mean. If we’re going to dismiss intuition on evolutionary grounds we’ll need to dismiss perception on exactly the same grounds. Well, so much for empirical knowledge. Adios. If you like that option, you might as well stop reading here. I don’t think you’ll get many followers, though.

A more challenging objection was raised at the turn of the century when a few philosophers learned about experimental psychology. Their first thought was “hey! We can use this!” and rebranded it for themselves as experimental philosophy. In fairness, Francis Bacon first came up with “experimental philosophy” almost 400 years earlier in Novum Organum, so I think philosophers are entitled to the expression.

Anyway, the experimental philosophers wanted to know whether intuitions about various philosophical examples varied across cultures or whether they were a kind of human universal. In their early work, they found cross-cultural variance, which many took as a reason to deny that intuition was any kind of road to the truth. If the results of rational intuition just vary from culture to culture, why should they be trusted at all?

As should be expected, there have been some replication complaints, other people arguing that the early results really do hold up, etc. I’m not getting into the weeds of all that here. The point I want to make is this: it doesn’t matter. Let’s grant the experimental philosophers all the empirical results their hearts desire. Because, guess what, there’s experimental evidence of cross-cultural variance about perception too. This is precisely the thesis of Richard Nisbett’s book The Geography of Thought: How Asians and Westerners Think Differently...and Why.

This is already getting a bit long, so I won’t walk you through Nisbett’s arguments. I want to make two points: (1) if cross-cultural variance undermines the evidentiary value of rational intuition, then it also undermines the evidentiary value of perception for the exact same reasons. This is bad because it leads to skepticism. (2) experimental philosophy depends upon perception to arrive at its conclusions (as do all experiments). Therefore, if we can’t count on perception to give us the truth, we can’t trust the results of experimental philosophy because of that very fact. Their whole approach is self-undermining.

In the end, if we trust perception, memory, nociception, proprioception, our innate theory of mind, and the rest of our suite of mental states to guide us to the truth, then we should trust rational intuition by the same reasoning. It’s not infallible, but then again nothing is. That’s OK.

1. The gene for this is carried on the X chromosome, so men are out of luck.

2. Or no one knows anything empirical, or about a world outside of their own minds, etc. I’m glossing over these differences.

3. Naming and Necessity (1980), p. 42.