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.

How can you tell who is a valid expert, and who is full of B.S.?

On almost any topic of importance you can find a mix of valid experts (who are giving you reliable information) and false but confident-seeming “experts” (who are giving you misinformation). To make matters even more confusing, sometimes the fake experts even have very impressive credentials, and every once in a while, the real, genuine experts are entirely self-taught.

Here are 12 signs we look for in an expert to help us determine whether they are trustworthy. 

1. They have deep factual knowledge

Let’s start with the obvious: for most topics, a lot of factual knowledge is required before you can have genuine expertise. This means that a genuine expert will have an impressive command of the relevant (non-debated) facts on the topic of their expertise. Thankfully, it’s a lot easier to tell if an expert has a strong command of the non-debated facts than whether they are correct about more controversial claims. 

2. They communicate their confidence levels

Not all knowledge is equally well-established. Even theories that are widely accepted enjoy different levels of support from the relevant evidence. When an expert regularly pretends that all their claims are equally well-established, they demonstrate they are willing to make you believe something is certain when it isn’t.

It’s a good sign that someone treats their subject with the nuance expected from genuine expertise, when they indicate how confident they are (e.g., “It’s been shown in many high-quality studies that…”, or “My best guess is…”), and they explain limitations in the evidence they are using (e.g., “this is unfortunately based on just one study, but that is all that currently exists”)

3. They admit not knowing

Genuine experts also sometimes say that they don’t know the answer to a question, or that the answer is generally not known by anyone. This is important because every topic will have some unknowns, and no expert can know everything about a topic. Telling you when they don’t know is a sign that, when they say they do know, they actually do know.

4. They tell you to look at sources other than themselves

This might happen when an expert doesn’t know the answer to a question, or when they want to help you go beyond the answer they can give you. Genuine experts don’t seek to be seen as a sole arbiter of knowledge or authority on a topic (which can be an indication that ego, rather than truth-seeking, is a primary motivation for them), but instead encourage you to look at resources other than the ones they have produced.

5. They use logic and evidence

Anyone can use rhetorical devices like emotional appeals, no matter how wrong they are, but a well-reasoned argument that uses valid logic and strong evidence will tend to point toward truth. Or, put another way, using strong logic and strong evidence is easier to do when you’re right, whereas emotional appeals are no easier when you’re right than when you’re wrong.  

6. They cite high-quality evidence

Some evidence is much more reliable than other evidence, and those who rely on the less reliable kinds when the more reliable kinds exist probably aren’t doing the best job they can at figuring out the truth. For this reason, genuine experts cite high-quality evidence when it exists (e.g., looking at multiple randomized controlled trials for causal claims) rather than low-quality evidence (e.g., just talking about personal anecdotes), and when high-quality evidence doesn’t exist, they cite the highest quality evidence that does exist.

7. They acknowledge the consensus

Consensus views among experts are more often correct than the idiosyncratic views of just one or two experts. The consensus will not always be right, of course, but often it will be the best understanding we have available. That’s why reliable experts are transparent about the degree to which their opinion differs from the majority of experts, provide reasoned explanations for any deviations, and they are cautious not to present fringe theories as mainstream. This shows a deep engagement with the topic of their expertise and also an adherence to ethical standards of honesty and accuracy in communication.

8. They change their mind

Genuine experts will change their minds about topics within their expertise in response to evidence and arguments. It’s hard to become an expert in something without having been wrong from time-to-time.

That means that anyone claiming to be an expert who has never changed their mind probably has not found and corrected their mistakes. Relatedly, changing one’s mind in response to evidence is also a sign of the epistemic humility associated with genuine expertise.

Of course, if someone has a long history of being wrong, that is evidence against them being a genuine expert, not in favor of it. But, since everyone makes some mistakes, if they make mistakes from time to time and then note they were wrong and improve their beliefs, that is a sign that they are following the evidence where it leads rather than continuing to believe what they do regardless of the evidence.

9. They Steelman

When you ‘straw man’ an argument, you misrepresent or oversimplify someone else’s position to make it easier to attack or refute. Instead of dealing with the actual argument, you replace it with a weaker version that distorts the original point, which you then argue against. The opposite of this is called ‘steelmanning’, and it involves presenting the strongest possible version of an argument you’re objecting to, even if it’s more robust than the one originally presented. This approach aims to strengthen the opposing case in order to facilitate a more genuine and constructive debate. 

The most reliable experts will accurately present the strongest arguments made by those that disagree with them while pointing out flaws in those arguments, rather than focusing on just weak arguments from the other side or just mocking the other side (including ad hominem attacks rather than focusing on the substance of the claims of the other side). This is important because knocking down a weak argument from the other side of a debate does little to show the other side is wrong; you have to refute the strongest claims of the other side to actually show they are wrong. Additionally, demonstrating a knowledge of the strongest arguments against your own position shows a deeper level of expertise than only understanding the opposing point of view at a superficial level.

10. They clearly explain their reasons for believing

The philosopher Daniel Dennett has said: “if I can’t explain something I’m doing to a group of bright undergraduates, I don’t really understand it myself.” This sentiment is echoed by philosopher John Searle, who said “In general, I feel if you can’t say it clearly you don’t understand it yourself.” 

When communicating with non-experts, genuine experts are often able to give clear, easy-to-follow (and, ideally, checkable) explanations for why they believe what they believe – without dumbing down the points. They avoid unnecessary jargon and technical language (which sounds smart but makes their arguments very difficult for their audience to follow). Not every genuine expert is able to do this, but the ability to do this well is a sign of genuine expertise. This is important because an expert who cannot explain their ideas clearly will end up requiring you to believe them based on their authority rather than engaging with the arguments themselves. And sometimes, people claiming to be experts will hide behind technical expertise and jargon so that you won’t notice that their arguments are actually weak.

11. They have a track record

Sometimes genuine experts will have track records of predictions or successes that you can check, and this provides direct evidence of their knowledge or skill. Unfortunately, this only applies to some fields, like chess masters, martial experts who fight in tournaments, experts who make public predictions about the economy or politics, etc.

12. They use multiple lenses

The world is complex and multi-faceted, and any one simple theory is going to fail to explain a lot of what’s really going on. For this reason, genuine experts tend to look at problems from multiple frames and perspectives; they don’t act as though one way of looking at things solves all problems, or that one solution works for all problems, or that one simple theory explains everything.

So the next time you hear claims from an alleged expert on a topic that is important to you, you may want to consider: how many of these signs of expertise do they exhibit? You can use this checklist, considering if they:

1. have deep factual knowledge
2. communicate their confidence levels
3. admit not knowing
4. tell you to look at sources other than themselves
5. use logic and evidence
6. cite high-quality evidence
7. acknowledge the consensus
8. change their mind
9. steelman
10. clearly explain their reasons for believing
11. have a track record
12. use multiple lenses

And if you’re seeking to be an expert in something yourself, you may want to ask yourself: “to what extent do I exhibit these traits?”Being able to discern genuine expertise from B.S. requires good judgment. If you’d like to improve your skills at making accurate judgments, why not try our Calibrate Your Judgment tool, created in partnership with Open Philanthropy.

This piece first appeared on Clearer Thinking.org on April 16, 2024, and first appeared on my website on April 22, 2024.

People often talk about what a problem “confirmation bias” is. But we rarely discuss what causes so many of us to search for information in a biased way.

Let’s explore some of the forces:

1. Echo chambers: our routine sources of information tend to support our worldview. Much of this is due to social ties (we tend to talk to people who are similar to us in age, geography, religion, etc.) We also trust news sources more if they share our basic ideology/assumptions. The authorities we look to will be the ones that agree with us on most of our fundamental assumptions (even if some of these assumptions could turn out to be wrong).

2. Soldier Mindset: as Julia Galef explains in her wonderful new book (the Scout Mindset), we are often not even TRYING to figure out the truth. We’re just trying to beat the other side or prove a point. In these cases, of course we have a biased search process.

3. Lack of doubt: when we’re really confident our basic premises are correct, we don’t see the need for a nuanced information search process. We’re going to go to whatever sources are convenient for filling in minor details, even if our beliefs have major unquestioned assumptions.

4. Advocacy: others are actively trying to get us to believe certain falsehoods. They do so through ads, websites, news, and other channels. For the most part, they themselves believe these falsehoods (promoting “the truth” as they see it), but occasionally it’s pure manipulation.

5. Fear of being wrong: it hurts to be wrong, especially if we’ve made the error publicly, have our identity tied up in the belief, or it challenges our understanding of the world or who to trust. We sometimes avoid finding out we are wrong the way we avoid touching a hot stove.

We don’t always seek out information in a biased way. For instance, when looking up driving directions or trying to figure out what paint to use to prevent water damage, we want the right answer, don’t have political biases, and usually have appropriate self-doubt and skepticism.

But we are liable to have a biased search for the truth when we are incentivized to have particular beliefs, such as when our social world supports just one perspective, when we’re trying to prove the other side wrong, when we have no doubt that we are right, when powerful others are devoting a lot of effort to persuade us, or when we’re too afraid of being wrong.

For more about this topic, you may want to check out my recent podcast episode with Julia Galef.