Our brains lie to us.

Deep Breadth
Jan 25, 2018 · 9 min read

How to try and see what’s really there.

If we’re adequately fortunate, we find that our evolutionary journey has gifted us with five(ish) major senses and a big squishy brain. Used together, they seem like a pretty good way to learn about the world.

As soon as we’re born (even a little earlier, actually [s]), we set our brains to the task of making sense of the persistent barrage of sights, sounds, shapes, ideas, feelings, and other sensations we’re confronted with.

Over time, we build up and refine models in our heads of the way things seem to be.

We can only expose ourselves to a tiny fraction of possible experiences and ideas, so we know our models are at best, incomplete.

But how do we know we can trust our interpretation of the limited experiences we do have?

The unfortunate truth is…

we can’t.

Briefly, we’ll try to address this by looking at:

  • the limits of our senses (illusions and how we simply lack senses)
  • extending our senses (translation via technology)
  • borrowing other people’s ideas (especially dead people)
  • how we’re just not that good at thinking clearly (mostly just bias)

The limits of our senses

The lies our brain tells us

Our brains make assumptions that might be useful shortcuts under certain circumstances, but that are deviations from what’s actually present.

Our brains can lie about color (square A and B are the exact same color). [s]

They can lie about proportions and shapes (stare at the cross and watch these celebrities turn into disfigured monsters). [s]

They can lie about motion. This is a static picture, not an animation (feel free to print it out on a piece of paper if you’re skeptical).

The snake illusion, illustrating peripheral drift [s]

They can also simultaneously lie about color and presence. Staring at the cross in the middle you should see a green dot appear where there is none, and staring longer, the purple dots should start disappearing entirely (it takes a while, maybe 15 seconds).

The Phi Phenomenon [s]

The faults of our vision are easily illustrated with optical illusions, but our brains can fool our sense of hearing as well:

This apparently infinitely accelerating rhythm is caused by fading between multiple rhythms with similar tempos.
This apparently infinitely descending Shepard scale consists of a superposition of sine waves separated by octaves.

Our sense of touch can be fooled too:

In the rubber hand illusion [s]

In the rubber hand illusion (and other body transfer illusions), the subject is fooled into thinking they have ownership over part of a body, or an entire body that is not there own. [s]

This is also related to phantom limbs. ~60%–80% of amputees report the sensation of an amputated or missing limb still being attached. [s]

Thermal grill illusion [s]

In the thermal grill illusion, subjects report feeling a searing pain when resting their hand on alternating warm and cool pipes, which individually, are not extreme in temperature. [s]

In one final example, subjects were fooled into thinking they were touching a short curved segment of metal that was actually straight, after viewing it through a prism wedge which made it look curved. [s]

Given these examples, there seems to be reason to think our brains are telling us analogous lies in other areas of our perceptions as well.

Aside from knowing our senses are lying to us, we also know they’re simply unable to detect much of what is physically present.

Our lack of senses

This seems to include most of the things that there are.

We also know we can only see a tiny sliver of the electromagnetic spectrum and we can’t sense magnetic fields or the trillions of neutrinos streaming through our bodies this very moment.

Of course, just because we can’t sense these things biologically doesn’t mean they’re not there or that we can’t sense them another way.

Most of us accept this readily, but if you need to be convinced, simply turn on a radio and realize that the electromagnetic waves containing the information you’re now hearing, were there the entire time- you just needed the device to translate them into a medium you could perceive (in this case, converting EM waves to sound waves).

So if we’re simply unable to perceive huge swaths of what exists, and our senses can lie to us about what we think we perceive, how can we figure out what anything is really like?

The radio is one good hint…and we’re also fortunate to have the company of the entire species in our endeavor to understand.

Extending our senses

Thermal cameras translate infrared radiation (heat) into visible light. [s]

Telescopes translate things too dim, old, big, and far away for us to see into spectacular images that we can.

Andromeda, our closest galactic neighbor (taken with NASA’s GALAX space telescope) [s]

Microscopes open up the world of cells and organelles which most of us already take for granted.

A white blood cell chases down a bacterium, being drawn by its chemical scent. [s]

Particle colliders and bubble chambers make the subatomic world tangible.

The bubble chamber image from Brookhaven National Laboratory in the 1960’s, tracing the path of particles including confirmation of the existence of the Omega-minus particle. [s]

Graphs of data from any tool are essentially abstract visual representations for things that really exist.

A graph of billions of collisions from the LHC providing the evidence for the existence of the higgs boson. [s]

These are just a few examples, but all extensions of our senses essentially provide us with raw data about reality that we otherwise could not access.

While it’s great that we can expose ourselves to aspects of reality beyond our biological senses, we’re still stuck with the task of assimilating this new world of phenomenon into our current frameworks of understanding.

One way to approach this is to work towards understanding how the tools themselves work.

This means going beyond grasping the light refraction and magnification used in telescopes and microscopes and working towards understanding more complicated tools like electron microscopes, gravitational wave detectors (interferometers), MRIs, thermal cameras, bubble chambers, and particle accelerators.

Essentially it means becoming just a little bit of an engineer.

Fortunately, we don’t have to start from scratch…we have the fairly unique ability to steal other people’s understanding. At least to some degree.

Comparing notes

Using this most deft of tools, other people can take an idea from their brain, and implant a representation of it into ours. Then we can analyze it, compare it with our own, assimilate it if we like it, and reject it if not.

We can even compare notes with dead people.

What sorcery.

We can only have one set of experiences first hand, but collectively we’ve built up mountains of knowledge through our cumulative experiences.

Of course, to grasp the peaks of knowledge, we must also understand the ascents.

Lucky, the adventurers that first blazed trails through these perilous routes left their paths behind. Many that have passed since leave their own hints and shortcuts, footholds and ropes. Later, ladders and stairs.

We now essentially have escalators to reach some of the most profound insights humanity has ever discovered (take for example, that heliocentrism is common knowledge, as is the existence of atoms, cells, and galaxies other than our own).

We just have to be shown where to get on and which mountains are worth climbing.

But still…standing at what appears to be the top of the mountain, how do we know if what we understand is right?

…we don’t.

But unless the mountain is built on a rickety foundation, we can be confident we’re at least closer to the truth than we were at the base.

Sadly, it might be that being able to borrow peoples ideas doesn’t matter, because…

We pretty much believe whatever we want.


When we compare the model of an idea in our head with the model of the same idea from someone else's head, if they look kind of similar, we might feel we’re on the right track.

Of course, it could be that we’re both just entirely wrong.

To check, we can compare our model with the models of as many people (and as many different kinds of people) as possible to look for trends and see where they overlap, and where they don’t.

If someone elses model for a idea is higher resolution than our own, and the person seems to know what they’re talking about, we’ll probably try to work on growing and extending ours to be a closer match.

That’s what we call learning.

What about when our conceptions are in direct conflict with someone else’s?

Sometimes, apparently contradictory perspective can both be correct.


Though other times (maybe most), ideas are truly mutually exclusive.

We don’t really like to have our understanding challenged. It’s uncomfortable to admit we were wrong and we don’t like having to revise our frameworks.

We’re equipped with countless biases and faulty heuristics to help us preserve our ideas just as they are.

We all have dozens of biases, but perhaps the most damaging in the pursuit of truth, is confirmation basis. We unconsciously give outweighed importance to anything that aligns with what we already believe and discount things that disagree. [s]

Thanks to the backfire effect, a subset of confirmation bias, when we’re exposed to valid evidence that contradicts deeply held beliefs (things we closely tie our identities around like religion or political alignment), we’re likely to respond by outright rejecting the evidence and holding onto our original belief even more deeply.

All this to say, as Richard Feynman put it, “the easiest person to fool is yourself.”

We can’t take our lenses of bias off, but we can try to understand how they’re warping our perspective and aim to correct for them to the best of our abilities.

Where do we go from here?

To summarize, there are a few things we can do to try to account for our faulty perceptions:

  1. Recognize the limitations of our biological senses
  2. Understand how the tools that extend our senses work, so we can more accurately interpret the aspects of reality that they’re translating
  3. Expose ourselves to as many perspective as possible and see where the highest resolution conceptions overlap, modifying our ideas to fit
  4. Try not to believe anything too strongly, learn to be okay with being wrong and updating our beliefs in light of new evidence
  5. Work towards recognizing and correcting for the lens’ of biases that we can’t take off

These suggestions are by no means the end-all-be-all path towards truth, but hopefully they’re at least a start.

Deep Breadth

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Big pictures, thresholds, and cross sections.