Put another way, rather than perceiving reality, we perceive the output of a long chain of noisy translations.

Let’s walk up this chain layer by layer, starting from the bottom (fundamental physics) and ending at the stories we tell. 

Layer 1: We only make measurements

On one common reading of quantum mechanics (part of the deepest description of reality that physicists have a reasonably high degree of confidence in), a fundamental object is the wave function. 

We don’t observe the wave function directly. We make measurements, and those represent properties, such as the position or “spin” of a particle. We can think of this as observing just one realization (or taking one branch) of the deeper thing. The wave function, in a sense, captures all of the realizations we might have observed but didn’t.

That means that at the most basic level, before biology or psychology even enter the picture, there’s already a chasm between us and the fundamental nature of things. 

Rather than reading reality, we sample a thin projection of it. We’re stuck accessing reality only through measurements. But that’s just the first layer of translation.

Layer 2: Measurements turn into signals

Measurements are not something you can directly experience. Your sense organs make the measurements. When light hits your eye, first a chemical reaction occurs, then this chemical reaction kicks off electrical signals – representations of the light (not light itself).

Your brain processes those electrical signals, and out of that, an experience is produced in your mind. Put another way, your brain creates a simulation, and that’s what you experience. For instance, in your brain’s simulation, you experience the vivid sensation of red. But there’s no such thing as red out there in the world – red exists ONLY in the simulations produced by our minds.

Out there in the world, light of certain frequency bands is hitting our eyes. Inside our minds, the experience of red is happening.

The same is true of sound, smell, warmth, and every other quality of experience: they are our brain’s rendering of the measurements made by our sense organs. They are not the measurements themselves, and certainly not the underlying reality.

Three distinct sorts of failures can occur at this layer.

First, the signal itself can be distorted, such as might happen if the optic nerve is damaged or if cataracts tint the light entering our eyes.

Second, the simulation that your brain creates can be unfaithful to reality, misrepresenting what’s there. We see this most clearly with optical illusions. 

The reason we find them interesting is that they lay bare ways our brain’s rendering of reality comes apart from reality itself. 

We can only tell this is happening because we can check our internal rendering against something indisputable to prove a mismatch (e.g., by using a ruler or checking the color of different pixels).

The unsettling implication is that the renderings we can’t easily check are sometimes misleading, too. But we lack the awareness or the right ruler to catch them.

The third distortion at this layer is that our simulations of reality always leave out information. For example, our eyes can’t see ultraviolet or infrared light, so those wavelengths simply never make it into our experience, no matter how carefully we look. Intriguingly, we don’t perceive a gap in the color spectrum. Presumably, that wouldn’t have been useful for our ancient ancestors, so evolution didn’t bother with it. We aren’t even naturally aware that other “colors” (well, really, frequencies) of light are possible. We feel as though we’re seeing the full spectrum (while bees and butterflies enjoy ultraviolet patterns on flowers that are hidden to us).

Every sense is like this. Each provides us with a window of information, which we use to simulate aspects of reality. A lot of information is silently dropped because it lies beyond the window frame. We remain convinced that these narrow portals into reality show the whole thing.

Layer 3: We bucket the simulation

A raw field of colors and sounds may be a partial approximation to how an infant sees the world, as its brain learns furiously how to structure things. But that isn’t yet a world you can act in. To use your experience effectively, your mind has to carve up experience. It has to decide that this region is a table, that one a person, and that other one, the floor.

This chunking happens automatically and below conscious awareness. It’s enormously useful. But it’s another layer of interpretation laid on top of an already-imperfect simulation, and it can distort things in its own ways.

For one thing, the boundaries we draw can simply be mistaken – we can mistake a coat on a chair for a person the moment we enter a room. Or, if you’re me, you can briefly think you see cats in the dark when on vacation because you see cats in the dark when you’re at home.

Our categories take genuinely complex things and force them into a bucket. You may, when walking in a park, stumble on a rare bird – the last of its species, on the brink of extinction. Your brain just says “bird”. 

Moreover, we sometimes get our chunks wrong. You walk by a fresh-faced man with long hair and incorrectly think “woman”. Or, in my case, you see a symbol tattooed on a classmate’s arm and think Swastika. It turned out to be the manji – a sacred Buddhist symbol representing good fortune.

Tremendous variation can hide inside even simple-seeming categories, let alone complex categories like “tree”, consisting of tens of thousands of species.

Buckets produce compression, and compression is what makes the world manageable, but sometimes a lot is lost in the process.

Importantly, the more you pay attention to a type of thing and the more you understand about it, the more refined and subtle your buckets are likely to become. That’s not just a tree. It’s a Sycamore tree. And it’s not just a Sycamore tree; it’s Platanus wrightii – an Arizona Sycamore. 

Layer 4: We ignore almost everything

Even with the compression achieved by this chunking up of reality, there’s far too much information for us to process, so our brain uses another heuristic: if something doesn’t draw our attention, it’s ignored.

When we’re told to carefully count how many times people pass a basketball, we can, with remarkable ease, miss the person in a gorilla suit that’s walking between them.

Or, if you’re having a conversation with me, and you ask me to close my eyes, then you ask me to recall what you were wearing, I’ll be clueless, despite having been looking at you moments ago. Heck, with my eyes closed, I may not even be able to tell you what I’M wearing. 

On the other hand, if you try the same thing with a person who works in fashion, they’ll not only be able to describe what you are wearing, but also make a guess about the brand.

We notice what we find interesting, important, or surprising, as well as what we’ve trained ourselves or been trained to notice. And we are unaware of most of the rest. This (in part) explains why eyewitness testimony has proven to be much more fallible than a lot of people assume. 

You didn’t know that person was about to rob the store you’re in, so even though they walked right in front of you, you have no recollection of what they look like. 

Even when you realized that they were robbing the store, your attention was drawn to the knife in their hand or the exit door, rather than the contour of their brow, lips, and nose.

Our limited attention acts as yet another filter on what makes it into our experience. But one layer remains.

Layer 5: We turn noticed chunks into meaningful ones

Even once you’ve chunked the world into objects and categories, and we’re actually paying attention to some of them, the process of perceiving isn’t complete. Your brain still has to decide what it all means. 

A Sycamore tree to Bob has no special significance, whereas to Sally it’s where she had her first kiss, and to Elio, it’s what his grandfather died under. To me, it was a phrase served to me in an ad when I was looking for a type of tree to use in this example.

Once we’ve chunked a scene, it gets woven into a story. Our reflective minds run on such stories.

The stories tell us what’s important, what’s threatening, and what’s good. But this final layer of interpretation is steered heavily by things that have nothing to do with the scene itself: our identities, our motivations, our worldviews, our past experiences, our anticipations, and our social groups.

This is why two people can look at an identical event – even identical data represented in a chart – and walk away with opposite understandings. They are running the same visual input through different meaning-making machinery constructed within different lives.

Of course, that’s not how this all feels. The meaning we make feels like it’s obviously the way things are – the one true story – or, not even a story – just reality itself.

We, of course, don’t think of the wave function that we collapsed (or took a branch of) with our measurements. Or the electrical signals that flow through the retina. Or even the bucketing we did to compress the information. We don’t, of course, pay attention to what we failed to pay attention to. And we rarely consider alternative stories our brains could have told us (but didn’t) about what we did pay attention to.

This may sound grim, but it’s not a complete epistemic disaster. Despite all this, we know a lot about how to get reality to do things for us. Science often works to discover new truths. Bridges rarely fall. Some stories are accurate, even if they aren’t complete.

The practical upshot of it all is epistemic humility. 

It helps to remember, from time to time, that what we’re experiencing is a model, a series of translations removed from whatever is actually out there. And to aim to make our estimates and opinions at least somewhat more uncertain as a result.

Doing so has a happy effect: it makes it easier to consider alternative perspectives that contradict our own. That’s useful societally, where there’s an overabundance of perspectives that are rigidly held. But it’s also helpful in relationships, friendships, and our work.

We can’t see reality directly – it’s not actually the sort of thing that’s capable of being seen. But we can, at least, stop mistaking the top of the stack for the bottom.

This piece was first written on June 30, 2026, and first appeared on my website on July 23, 2026.

1. Occamism: the simpler a moral theory is, the more likely it is to be true. Hence (a priori), the most probable two moral theories are that (a) everything is permissible or that (b) nothing is.

2. Majoritarianism: an action is morally right if and only if the majority of conscious beings capable of understanding that action and its consequences think it’s right.

3. Restraintism: if you have the desire to do something, then you don’t get moral credit for doing it (since the action is satisfying your OWN desire).

So, to maximize the good you do, become the sort of person that hates everyone and doesn’t want to help – then help a lot anyway!

4. Infinitarianism: god is infinite goodness. A finite number plus an infinite number is just the same infinite number again (left unchanged). All actions humans take can only create finite good. Hence, no human action can change the total goodness in the universe.

5. Virtue ethics prime: virtue ethicists are right – being good is only about having good character. But it turns out the only character strengths that count as morally good are cleanliness and moderation.

6. Purely positive utilitarianism: the only thing that matters morally is the sum total of happy mental states (suffering is irrelevant and doesn’t impact the calculation). Hence the attempts to airdrop MDMA into the forests.

7. Qualiaism: some actions are objectively morally right, and others are objectively wrong, but the criteria determining what is right is unique to each human and inaccessible to anyone who is not that person. Hence, each of us must discover our own unique, objectively-true morality.

8. Tegmark morality: for every mathematical structure, there exists some universe for which that structure is a complete description of what’s morally right. Hence, integer addition is a complete and correct moral theory (in some universe).

9. Similaritarianism: how kind you need to behave is determined by how similar someone is to you.

Hence you should be very nice to your parents, less so to strangers, and even less so to a rock. Since you are most similar to yourself, self-kindness is most important of all.

10. Unnatural law: we’re probably living in a simulation. Whoever the simulator(s) were, they were/are vastly more intelligent than us and hence far more likely to understand morality. We must study this creation of theirs (that we call reality) to figure out what’s good!

This piece was first written on March 19, 2021, and first appeared on this site on April 23, 2023.

We often say things like “I believe…” and “they think that…”

But what do we really mean by a “belief”? It’s notoriously tricky to define.

For starters, we sometimes think of beliefs in binaries (true vs. false) and other times in probabilities (a 90% chance of coming true). We sometimes would be willing to bet on our beliefs (“I’ll bet you $100 that New York City is not the capital of New York State”), and other times we wouldn’t be willing to bet (e.g., that your favorite team will win the Super Bowl, even though you may feel confident about it). It seems, sometimes, like we don’t fully believe our beliefs (e.g., we say, “I know it’s not dangerous,” and mean it, but then act as though it’s dangerous).

So what’s going on here? My theory: what makes discussing beliefs so confusing is that there are actually many different mental states we can have that are “belief-like.” In other words, beliefs are not one type of thing. They come in many forms.

We usually lump these divergent forms together, which creates a lot of confusion. At best, we divide them into dichotomies like explicit, cognitive “beliefs” vs. automatic “aliefs,” which still combine disparate forms together.

Below is my ambitious attempt to distinguish all the different belief-like states our minds can have.

I’m sure I missed some. So, I’d be very interested to know: what types of beliefs am I missing?

FORMS OF BELIEF

Beliefs On Reflection

Endorsed Belief: there are some things we’re willing to sincerely say we believe (or willing to say we’re X% confident about), and this is a form of belief – the things we “believe” that we believe.

Ex: you write as a social media post, “I believe healthcare should be free for everyone,” and there is no doubt in your mind that you really do endorse this.

Simulation Belief: we can ask ourselves hypotheticals like: “if I suddenly took my clothes off in the street, how would people react?” Our brains will then simulate the scenario and provide the best guess of what will happen. This is a form of belief about what would happen.

Ex: you consider how your friend would react if you told them you don’t like their haircut, and your belief is that they would be angry at you.

Automatic Beliefs

Anticipation Belief: our brains constantly predict what is about to happen (based on current sensory input, knowledge, and what happened recently). When these anticipations are far off from what actually happens, we feel surprised. These are a kind of “belief” about what is about to happen in the next moment.

Ex: you knock over a full cup of coffee and anticipate it will spill onto the ground. If it doesn’t spill, you will be surprised.

Sensed Belief: when someone makes a claim, such as “most pirates are ninjas,” we have a felt sense of whether we believe that statement or not (and how strongly/confidently we believe it). This is just a feeling, but it is a feeling about our level of “belief.”

Ex: you say to yourself, “I believe I am a good person,” and then you consider that statement carefully to see if you really FEEL like you believe it.

This idea relates to techniques like Focusing, where you learn to pay attention to the “felt sense” of whether a statement resonates with you.

Emotional Belief: our emotions activate in specific sorts of situations (e.g., risk -> anxiety, contamination -> disgust). So if our emotions are activated, they can be interpreted as a form of “Emotional Belief.” If I’m anxious about X, on some level, I believe X could go badly.

Ex: you know it’s totally safe to walk across the balance beam suspended above the pit of foam cubes, but your heart is pounding in your chest, and your sympathetic nervous system seems convinced you’re about to plummet to your death.

Intuitive Moral Belief: we have feelings about whether most things are good, neutral, or bad (and to what degree). For instance, you might like tea and hate coffee. You might like Biden and dislike Trump. These are beliefs of a sort – about what’s good.

Ex: are guns good or bad? What about nuclear power? Youth? Avocados? Spiders? If you pay close attention, you’ll probably realize you have an automatic sense of how good or bad these things are.

Self-serving Belief: sometimes, we want something to be true badly, and we won’t even allow the possibility that it’s false (e.g., because the thought that it could be false gives us pain, and so we immediately flinch away from that thought).

Ex: Some people might say, “my partner has never cheated on me,” without actually even considering whether it could be true.

Association Belief: we associate ideas with each other. For instance, we might associate milk with health (because of those “got milk” commercials) and Segways with nerds. These are a sort of implicit belief about the nature of these things (health effects / who uses them). (These beliefs can also be thought of as automatic or implicit memory-based beliefs.)

Ex: do you associate cities with smog? Do you associate French people with an enjoyment of food?

Implied Belief: you have probably never considered whether 384883828382553 is a number, but you already believed it is, in the sense that you have beliefs about what makes something a number. By implication, they imply it is one. Beliefs can imply other beliefs.

Ex: if you believe all men are mortal, and you believe Elon Musk is a man, you also, in a sense, believe that Elon Musk is mortal, even if you’ve never thought about the mortality of Elon Musk.

Memory-based Beliefs

Autobiographical Belief: suppose someone asks you if you have ever eaten Flaming Hot Cheetos. If you can recall an instance of doing so, you’ll say you have eaten them; otherwise, you won’t. One type of belief is what we can recall being true. Another way this can manifest is if we’re considering a question (like: “Is Sally a flaky friend?”) we may try to recall an instance of her being flaky, and if we can, we conclude she is flaky, whereas if we can’t, we are more likely to conclude she is not.

Ex: have you called a friend on their cell phone in the past seven days? If you can recall a case of doing so, you’ll believe it’s true. If not, you’ll very likely believe it’s not.

Memorized Belief: you can believe a statement in the sense of memorizing that the statement is supposed to be “true.” For instance, if you’re taught from age three that “Morloc is the sky god,” You say “Morloc is the sky god” and believe you believe it. You may not know what it means.

Ex: TV rots your brain. Opposites attract. Do you believe these statements are “true” because you heard that they were before you’ve had a chance to reflect on whether or not they really are true?

Elicited Beliefs

Generated Belief: when we are asked a question (by ourselves or others), we usually will generate an answer (e.g., “Why did you do that?” -> “Because I was angry”). This answer is a kind of belief related to the query. On reflection, though, we may decide we don’t believe it.

Ex: your friend asks you whether you want to go camping. You immediately blurt out “yes” – but then you immediately start considering whether or not you would actually enjoy camping.

Queried Belief: suppose you are shown a picture of a person and asked to “predict where this person is from.” A guess will likely appear in your head. In a sense, you have a belief that this person is from this place (arguably even if you have not yet run that mental query).

Ex: What country in the world do you think has the smallest landmass? Your brain may well generate a guess upon hearing that query.

Reactive Belief: we may find that a thought pops into our head (e.g., “Joe is a jerk”), and some people may view merely having this thought as a form of belief. Of course, upon reflection, we may or may not agree with the thought.

Ex: upon seeing Marty throw the bowling ball into the next lane by accident, you may have the thought, “Marty is awful at bowling.”

Behavioral Beliefs

Enacted Belief: sometimes, we believe something in order to create a state of affairs that is true by virtue of having the belief. For instance, we may think that “good people believe X” and we find that we can get ourselves to believe X, so we try to believe it, or we may think “my company will succeed if I believe it strongly enough” and so we push ourselves to believe we will succeed in hopes of making it true (e.g., dismissing any thoughts that we will fail, and trying to focus just on evidence in support of our future success).

Ex: someone who believes deeply in the placebo effect might do everything they can to believe the medicine will make them feel better, with the theory that, if they believe hard enough, it will work – which means then that they will be justified in that belief. (H/T Alli Smith and Annie Kotowicz.)

As-if Belief: sometimes we believe something in the sense of simply acting as though it is true, whether or not we would say we are highly confident in it. For instance, we might have heard a rumor that our neighbor once went to prison for molesting a child. We are considering how to act towards this neighbor. We may conclude that, even though there is uncertainty (since it’s just a rumor), we will act “as if” it is true – even though, if pressed on the topic, we will say we are uncertain whether it is true. Or we could decide the opposite (to act as though it is NOT true, on the principle that we shouldn’t act as if someone committed a criminal act unless we have strong evidence – like the principle of being “innocent until proven guilty”). 

Sometimes these “as-if” beliefs are much deeper; for instance, we might act “as-if” induction works, even if we know we can’t provide strong arguments in favor of it, or we might act “as-if” god doesn’t exist, even if we aren’t really sure about it. Or we might act “as-if” we have a death wish (e.g., by engaging in extremely risky behavior), even though we don’t think we have any desire for self-harm. H/T to Pepe Le Pew for inspiring this belief type.

There are many forms of belief. In plenty of cases, it’s unnecessary to differentiate between them, but on complex questions of human psychology, we may need to get granular with the idea of “belief” to really understand what’s happening.

Consider advanced cases like these, that are hard to make sense of without a nuanced perspective of the different forms of belief:

• Why do people who are absolutely convinced they’re going to heaven get scared of dying?

• Why do people claim that Trump or Biden is definitely going to win but then refuse to make a bet on that claim (even though normally they enjoy betting)?

• Why do we say things like “I believe in love,” even though, when asked what it means, we may struggle to explain it, and we may not have thought in detail about its meaning before?

This essay was first written on October 11th, 2020, and first appeared on this site on January 14th, 2022.

This way of deciding between options is quite common. When someone asks us whether we want an apple or an orange, we often will imagine what the experience of each is like, and see which simulated experience feels the most positive. So sometimes when we say that we “want” something, what we mean is that when we imagine that thing it produces a positive experience.

Perhaps it was no coincidence that my memory of swimming involved the peak intensity of the experience (jumping into the cold water was a more intense experience for me than any other aspect of swimming). There is a rule of thumb known as the peak-end rule which says that we base our judgement of how good or bad experiences are mostly on their peak intensity and the way that they end. So if an experience is quite pleasant on average but contains a few seconds of very negative experience and ends poorly, we are likely to view that experience after the fact as having been unpleasant. For swimming, not only is the peak intensity rather unpleasant for me, but the ending is as well. It often involves walking around wet, cold, and smelling of chlorine.

Some remarkable studies have been performed that confirm half of this peak-end rule. They involve giving 50% of a group of people (selected at random) an unpleasant experience, and the other half the same unpleasant experience with a shorter, somewhat less unpleasant experience tacked on the end of the primary experience. The latter group views the entire experience as having been less unpleasant than the former group does, and would be more willing to subject themselves to the experience again. This holds even though the latter group had more total moment to moment unpleasantness than the former group, and were subjected to unpleasantness for longer.

A similar issue to my swimming one can arise for experiences that we have never actually had before. When deciding whether we want them, we imagine what they are like, but this can be quite different from what they are in fact like. I have heard it said that this arises particularly often for sexual fantasies. People believe that they would really enjoy a particular experience (they do, in fact, enjoy imagining having that experience) but when they actually have it they find that it is unenjoyable in practice. And something akin to this is at risk of happening when people consider the question of whether they want to have children. If the visual image that the thought of having kids produces is one of sitting by a fireplace while beaming proudly at two well-behaved children with beaming smiles, then the feeling produced may well be “I want that!” But if the image is instead one of changing diapers, or trying to get your kids to stop screaming, or being woken up by a baby after two hours of sleep, the resulting feeling of wanting could be quite different.

Consider the problem that arises from these considerations. When we decide whether we want something, we often rely on our simulation or memory of that thing to make a decision. But our simulations and memories of experiences are not the same as the experiences themselves, and can be inaccurate representations. When we imagine something we run the risk of not understanding what that experience is really like. Therefore, when we say that we want something, we may only want it because of the particular aspects of it we happened to simulation, or because of inaccuracies in our simulation. However, if we force ourselves to think of many different aspects of the experience in question, rather than just one small part, that may lead to less arbitrary conclusions about what it is that we want. If your wanting depends heavily on the fact that (by chance, or due to a certain design feature of the human brain) you happened to imagine a particular part of the experience rather than another part of it, then the fact that you think you want it may not be very meaningful.

Nowadays, when I think about whether I want to swim, I try to get myself to imagine what the vast majority of the experience is like, not just the beginning and the end. I imagine actually swimming in the pool, which produces a positive mental state, rather than only thinking about jumping into the pool, which produces a negative one. As you’d expect, this produces a stronger feeling of wanting to swim than I had before.

Thinking along these lines, each of us can divide all things that exist or seem to exist into a few categories:

1. Those things that exist in physical reality that also have a representation in my simulation. An example of this would be some particular car that I see on the street. There are atoms (or quantum wave functions at least) in the universe that correspond to this car, and there is a visual experience in my simulation that represents this car. After I look at this car and walk away, my simulation continues to have the concept of this car, at least until I have forgotten about it. So the car exists in my simulation, but it also exists in physical reality as a bunch of atoms (though there is no dividing line in physical reality between where the car atoms end and not-car atoms begin, that dividing line too is a property of the simulation). Color is another thing in our simulation that corresponds to physical reality, but is of course only a representation of it. There is no “redness” in space, redness is something that we experience. What there is in space is electromagnetic radiation, some of which produces an experience of redness in our simulations after it hits the simulation/reality interface that we call our eyes.
2. Those things that exist in physical reality but have no representation in my simulation. This would include a particular planet in another galaxy that I’ve never heard of. Although I have the concept of planets existing, this particular planet has no representation in my simulation of reality.
3. Those things that exist in our simulation but are not representations of specific things in physical reality. An example of this would be a hallucination (sure, there are bunnies in physical reality, but that particular bunny that you think is laughing at you now and doing head stands doesn’t actually correspond to any set of atoms). Perhaps a more interesting example from this category though would be impurity. A dish is unclean, Jewish custom says, if it has touched both milk and meat. This contamination property continues to hold even after the plate is scrubbed completely clean, even if every atom of milk and meat are removed. Suppose that a man who lives by this system of thought is given a plate, and then he is told that it was recently used to eat both meat and milk. Regardless of whether that claim is true, so long as he believes it the plate will suddenly gain the property of uncleanness in his simulation. He may experience the sense of this uncleanness quite strongly, and the thought of eating from that plate may even cause him to feel disgust.

One thing that is odd about living inside a simulation (as we each are), is that aspects of the simulation that don’t correspond to anything in physical reality can feel just as real as those that do correspond. For instance, someone I know once had a schizophrenic period where they became convinced that certain objects in their kitchen were, in fact, quite evil. This evilness was completely convincing and quite overwhelming. But what does it mean for an object to be evil? Evilness surely is not a property of atoms, quantum wave functions, or physical objects, but a property of representations of things inside our simulations. Normally we only associate this property with intelligent beings, but when the simulation goes haywire it can get associated with inanimate things. Just as we think some particular clown nose is red (i.e. our simulation contains the experience of redness which our brain links to its concept of that clown nose), we could end up thinking that some particular bar of soap is evil (i.e. our simulation contains the experience of evilness which our brain links to its concept of that soap).

Influences: Michael Vassar