We often talk as though we are in direct contact with reality – as though our eyes show us the world, and our minds read off the facts. But between whatever reality fundamentally is and the experience you’re having right now, there are a surprising number of layers. At each layer, two types of error happen: information gets left out, and bias creeps in. By the time experience reaches you, there’s the potential for a great deal of both to have accumulated.
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.
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