Limited Senses

Limited Senses

  • We inhabit a sphere of sensory perception that is not what the universe actually is.
  • Our brain interprets a boulder as in penetrable because it is impenetrable for our bodies, but this is not what it actually is.
    • Matter is real to my senses, but they aren't trustworthy. If Galileo or Copernicus had accepted what they saw, they would never have discovered the movement of the earth and planets.
  • Albert Einstein, Einstein and the Poet
    • The distinction between past, present, and future is only a stubbornly persistent illusion.
  • Albert Einstein
    • Our conscious model of reality is a low dimensional projection of the inconceivably richer physical reality surrounding and sustaining us. Our sensory organs are limited: They evolved for reasons of survival, not for depicting the enormous wealth and richness of reality in all its unfathomable depth.
  • Thomas Metzinger (Contemporary German philosopher)
  • Through our evolution as a species of animal, we've evolved only the senses needed for us to live in our natural environment, and no more than that. No resources have been spent by our bodies developing senses that were not strictly necessary in our evolutionary history.
  • As a consequence, we perceive only a narrow band of what is truly in the universe. The light, sound, and texture that we sense of the universe around us is just a tiny fraction of what is really going on around us.
  • Take for instance electromagnetic radiation. It has an extraordinary waveband, but we see only the tiniest fraction, that accounts for all of the colours that we know.
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  • Other animals with different evolutionary environments have a slightly different 'visible spectrum'.
  • Many birds, insects, and fish can see in near-UV, and the Mantis Shrimp can actually tune its vision to different wavelengths to adapt to its environment. These adaptions are a result of their natural environment that places more emphasis on identifying corals or flowers that use this part of the spectrum, and which may allow these animals to see colours that we will never be able to perceive.
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  • The Mantis Shrimp has 16 types of colour receptor cones in its eyes, compared to our 3. It's world may be a kaleidoscope of unimaginable colour.
  • But our limitations don't just stop with the visible spectrum. It also applies to sound, size, speed, and other domains. Our senses don’t even register huge things going on around us, like electromagnetic fields, or if we're being bathed in ionizing radiation.
  • Different animals have different biological configurations, and they sense the world differently . A pond insect would be very concerned with surface tension, a bird would be very aware of air currents, a whale may have no concept of a flat plane like we do, and may see the sea not as blue but as crystal clear. A mantis shrimp may see every part of every object as a different colour. A dog deduces things about its environment based on smell - and would be very conscious of wind direction and speed.
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  • We have built tools that translate these spectrums into ones we can perceive
  • Slow motion cameras to see the very fast
  • Timelapse cameras to see the very slow
  • Infrared cameras that can detect heat
  • UV cameras that detect UV light
  • Telescopes of increasing power to see the distant
  • Microscopes of increasing power to see the very small
  • Microphones to detect frequencies above and below our range of hearing
  • Smoke machines that scatter the paths of light
  • Interestingly, we don’t really have anything for smell or touch.
  • All of these things combined expand our limited senses and move a few limited steps closer to seeing the universe as it truly is.
  • Imagine that we are cave dwellers within a gargantuan cavern that's pitch black, except we've been equipped with a small lantern that illuminates some area around us. These are our natural senses. Our tools like microphones and telescopes lets us as a species illuminate progressively further into the cavern. As tools like this become more available for people, this perception slowly becomes available to the individual level.
  • Augmented reality, being a mobile device with cameras, microphones, location data, personalised info, and access to all the world's knowledge via the internet may bridge the differential between our knowledge as a species and our individual experience of the world, and may turn this lantern into a floodlight.
  • Imagine a mobile device that if pointed into the night sky, can zoom into a star, display an encyclopaedic brief, and then display artist's impressions of the planets that orbit it. Or one that can identify species with an image or from listening to their sounds, along with a brief on their characteristics and how they fit into the local ecosystem. This kind of ubiquitous device would expand the frontiers of experience considerably.
  • Even then, these are only the characteristics of the universe we can detect with our instruments. There are a lot of unanswered questions, such as dark energy and dark matter, and what is beyond the observable universe, that is beyond our abilities at the moment, which form the frontiers of knowledge for our species.
  • Anus_Blenders 82 points 10 hours ago*
  • I'm sure there is something like this. We're missing out on most of the EM spectrum, for example.
  • Imagine how insane the night sky would look if we could see X-rays, IR light, and radio waves. The ground would literally glow during the day because of black body radiation, and slowly cool at night like the burner on a stove after you turn it off. The ground would be a rainbow of color from artificial sources like cell phone towers.
  • What if we had a sensory organ that directly detected air pressure? We can sort of do that with our ears, but what if it was more direct? Like an analogue to sight? You would see a colors of a pressure wave every time someone talked, whistled, sang, or even moved. We could literally see a high pressure front moving in. Weather would be even more beautiful than it already is. Clouds would be a rainbow of color. Tornados would blow our mind. Perhaps we'd develop a language based on this sense, rather than sound. Super, psychedelic sign language.
  • Or imagine if we had an organ that detected biological processes associated with life. We could just stand in a field and know where all the insects and burrowing rodents are. Plant life would be a different "color" than animals, and big animals would "look" different than small animals. Cities would be completely saturated with the human "color" and the Amazon rainforests would be an entire spectrum everywhere you look. Some people might not like this feeling. To them it might be like looking into the sun. They'd retreat to places like Death valley, which would be something like a nice, relaxing pastel.
  • Reddit community, If we had no eyes then we would be unaware of the existence of color. What if we are are missing an entire aspect of everything simply because we do not have the organ to detect it?
  • It is also quite possible that we do not truly use even a fraction of the senses that we *do* have. We cognitively filter out a lot by just not paying much attention. If you stand in quiet meditation and watch the wind by the patterns of trees blowing, their sounds and the clouds moving. Especially touch, taste, and the sensations of your own body.

The theories that govern the very small, very large, and very fast seem unfamiliar and unintuitive, precisely because our brains evolved in our 'middle world', and we don’t recognise the emergent patterns of these worlds.

"Queerer than we can suppose" comes from J.B.S. Haldane, the famous biologist, who said, "Now, my own suspicion is that the universe is not only queerer than we suppose, but queerer than we can suppose. I suspect that there are more things in heaven and earth than are dreamed of, or can be dreamed of, in any philosophy." Richard Feynman compared the accuracy of quantum theories - experimental predictions - to specifying the width of North America to within one hair's breadth of accuracy. This means that quantum theory has got to be in some sense true. Yet the assumptions that quantum theory needs to make in order to deliver those predictions are so mysterious that even Feynman himself was moved to remark, "If you think you understand quantum theory, you don't understand quantum theory."

Science has taught us, against all intuition, that apparently solid things, like crystals and rocks, are really almost entirely composed of empty space. And the familiar illustration is the nucleus of an atom is a fly in the middle of a sports stadium and the next atom is in the next sports stadium. So it would seem the hardest, solidest, densest rock is really almost entirely empty space, broken only by tiny particles so widely spaced they shouldn't count. Why, then, do rocks look and feel solid and hard and impenetrable? As an evolutionary biologist I'd say this: our brains have evolved to help us survive within the orders of magnitude of size and speed which our bodies operate at. We never evolved to navigate in the world of atoms. If we had, our brains probably would perceive rocks as full of empty space. Rocks feel hard and impenetrable to our hands precisely because objects like rocks and hands cannot penetrate each other. It's therefore useful for our brains to construct notions like "solidity" and "impenetrability," because such notions help us to navigate our bodies through the middle-sized world in which we have to navigate.

Moving to the other end of the scale, our ancestors never had to navigate through the cosmos at speeds close to the speed of light. If they had, our brains would be much better at understanding Einstein. I want to give the name "Middle World" to the medium-scaled environment in which we've evolved the ability to take act - nothing to do with Middle Earth. Middle World. (Laughter) We are evolved denizens of Middle World, and that limits what we are capable of imagining. You find it intuitively easy to grasp ideas like, when a rabbit moves at the - sort of medium velocity at which rabbits and other Middle World objects move, and hits another Middle World object, like a rock, it knocks itself out.

Unaided human intuition schooled in Middle World finds it hard to believe Galileo when he tells us a heavy object and a light object, air friction aside, would hit the ground at the same instant. And that's because in Middle World, air friction is always there. If we'd evolved in a vacuum we would expect them to hit the ground simultaneously. If we were bacteria, constantly buffeted by thermal movements of molecules, it would be different, but we Middle Worlders are too big to notice Brownian motion. In the same way, our lives are dominated by gravity but are almost oblivious to the force of surface tension. A small insect would reverse these priorities.

Simply not aware

This is the biggest factor. See Our Reality is Filtered


Too fast


Too slow

The movement of the planets and the sky

Weather rolling past like an ocean

Planes flying in and out

Traffic ebbing and flowing

The growth of mould



Size, aka the orders of magnitude of the universe

  • At 10^-32m is thought to exist a foam of twisted spacetime (Quantum foam).
  • 10^-24m cross section radius of 1 MeV neutrinos.
  • 10^-22m Top Quark, the smallest quark.
  • 10^-20m Bottom and Charm quarks.
  • 10^-18m Up and Down quarks.
  • 10^-16m Protons and Neutrons.
  • 10^-14m Electrons and nuclei.
  • 10^-12m Longest wavelength of gamma rays.
  • 10^-11m Radius of hydrogen and helium atom.
  • 10^-10m Radius of carbon atoms.
  • 10^-9m Diameter of the DNA helix.
  • 10^-8m Smallest virus (Porcine circovirus).
  • 10^-7m Largest virus (Megavirus).
  • 10^-6m X Chromosome.
  • 10^-5m Typical size of a red blood cell.
  • 0.1mm Width of human hair.
  • 10mm Width of an adult human finger.
  • 1m Height of an infant human being.
  • 10m Argentinosaurus is the biggest dinosaur discovered yet (30 to 35 meters). Human figure is for comparison. In reality humans and dinosaurs didn't live at the same time.
  • 1km Diameter of Barringer Crater in the northern Arizona desert (1186m).
  • 100km Jamaica Island (235km long).
  • 10000km Diameter of planet Earth (12,742 km).
  • 10^8m Moon's orbit (770,000km).
  • 10^9m Diameter of the Sun (1391400km).
  • 10^11m Diameter of the inner Solar System. (600,000,000 km)
  • 10^13m Diameter of the Solar System.
  • 10^15m Outer limit of the Oort Cloud.
  • 10^16m Distance to Alpha Centauri.
  • 10^18m Messier 13 globular cluster.
  • 10^20m Diameter of the Milky Way Galaxy.
  • 10^22m Local Group of galaxies including Milky Way, M31(Andromeda), M33, SMC, LMC and smaller galaxies.
  • 10^23m Typical galaxy cluster (2 to 10 Mpc).
  • 10^24m Laniakea Supercluster of galaxies. (160 Mpc)
  • 10^25m End of Greatness ("Cosmic web" structure).
  • 10^26m Diameter of the observable universe sphere.
  • Pablo Carlos Budassi, Orders of magnitude. The above image can also be purchased poster-size here.

Too large

Even though we don’t easily perceive the things that are much, much larger than us, we still exist within their context.

Our environment exists within a flux of larger phenomena: the weather, the rotation of the spheres, the radiation of the sun. If any of these change, the environment in which life and civilisation balances will burst.

  • It took until the early 20th century to really come to understand the world of the 'very large', i.e. astronomical objects.
  • Below are a handful of the transformational discoveries in astronomy. None of these things are obvious with the naked eye, and each took centuries of technological and scientific growth to uncover.
  • Astronomical bodies are not perfect heavenly spheres
  • The medieval followers of Aristotle, first in the Islamic world and then in Christian Europe, tried to make sense of the lunar spots in Aristotelian terms. Various possibilities were entertained. It had been suggested already in Antiquity that the Moon was a perfect mirror and that its markings were reflections of earthly features, but this explanation was easily dismissed because the face of the Moon never changes as it moves about the Earth. Perhaps there were vapors between the Sun and the Moon, so that the images were actually contained in the Sun's incident light and thus reflected to the Earth. The explanation that finally became standard was that there were variations of "density" in the Moon that caused this otherwise perfectly spherical body to appear the way it does. The perfection of the Moon, and therefore the heavens, was thus preserved.
  • The telescope delivered the coup de grace to attempts to explain away the Moon's spots and to the perfection of the heavens in general. With his telescope, Galileo saw not only the "ancient" spots, but many smaller ones never seen before. In these smaller spots, he saw that the width of the dark lines defining them varied with the angle of solar illumination. He watched the dark lines change and he saw light spots in the unilluminated part of the Moon that gradually merged with the illuminated part as this part grew. The conclusion he drew was that the changing dark lines were shadows and that the lunar surface has mountains and valleys. The Moon was thus not spherical and hardly perfect.
  • Al Van Helden, The Moon
  • Close up of the moon
  • The Milky Way is composed of billions of stars
  • I had intended to depict the entire constellation of Orion, but I was overwhelmed by the vast quantity of stars and by the limitations of time, so I have deferred this to another occasion. There are more than 500 stars distributed among the old ones within limits of one or two degrees of arc… I have observed the nature and the material of the Milky Way… The galaxy is, in fact, nothing but a congeries of innumerable stars grouped together in clusters… And what is even more remarkable, the stars which have been called “nebulous” by every astronomer to this time turn out to be groups of very small stars arranged in a wonderful manner.
  • Galileo Galilei, quoted in Galileo saw countless stars
  • The density of stars in the bulge of the Milky Way
  • Stars are actually other suns
  • In 1838, Friedrich Bessel for the first time measured the distance to a star without any assumptions about the nature of stars and found it to be enormous. Distances to other stars followed soon, and then people could calculate the true brightnesses of stars, corrected for their distance to us, and discovered them to be about as bright as the Sun. When other things about the Sun were also found to be like those of stars, such as its surface temperature and chemical composition, then the proof was finally here that the Sun is a star.
  • Louis Strous, Who discovered that the Sun was a star?
  • Other galaxies exist (then called 'island universes')**
  • In astronomy, the Great Debate, also called the Shapley–Curtis Debate, was an influential debate, held on 26 April 1920 at the Smithsonian Museum of Natural History, between the astronomers Harlow Shapley and Heber Curtis.
  • The debate concerned the nature of so-called spiral nebulae and the size of the universe, specifically whether distant nebulae were relatively small and lay within the outskirts of the Earth's home galaxy or whether they were in fact independent galaxies, implying that they were exceedingly large and distant.
  • The two scientists first presented independent technical papers about "The Scale of the Universe" during the day and then took part in a joint discussion that evening. Much of the lore of the Great Debate grew out of two papers published by Shapley and by Curtis in the May 1921 issue of the Bulletin of the National Research Council. The published papers each included counter arguments to the position advocated by the other scientist at the 1920 meeting.
  • Shapley was arguing in favor of the Milky Way as the entirety of the then known universe. He believed that "spiral nebulae" such as Andromeda were simply part of the Milky Way. He could back up this claim by citing relative sizes—if Andromeda were not part of the Milky Way, then its distance must have been on the order of 108 light years—a span most astronomers would not accept. Adriaan van Maanen was also providing evidence to Shapley's argument. Van Maanen was a well-respected astronomer of the time who claimed he had observed the Pinwheel Galaxy rotating. If the Pinwheel Galaxy were in fact a distinct galaxy and could be observed to be rotating on a timescale of years, its orbital velocity would be enormous and there would clearly be a violation of the universal speed limit, the speed of light. Also used to back up his claims was the observation of a nova in the Andromeda "nebula" that had briefly outshone the entire nebula, constituting a seemingly impossible output of energy were Andromeda in fact a separate galaxy.
  • Curtis on the other side contended that Andromeda and other such "nebulae" were separate galaxies, or "island universes" (a term invented by the 18th-century philosopher Immanuel Kant, who also believed that the "spiral nebulae" were extragalactic). He showed that there were more novae in Andromeda than in the Milky Way. From this he could ask why there were more novae in one small section of the galaxy than the other sections of the galaxy, if Andromeda was not a separate galaxy but simply a nebula within the Earth's galaxy. This led to supporting Andromeda as a separate galaxy with its own signature age and rate of nova occurrences. He also cited dark lanes present in other galaxies similar to the dust clouds found in the Earth's own galaxy and massive doppler shifts found in other galaxies.
  • Curtis stated that if van Maanen's observation of the Pinwheel Galaxy rotating were correct, he himself would have been wrong about the scale of the universe and that the Milky Way would fully encompass it.
  • […]
  • Due to the work of Edwin Hubble, it is now known that the Milky Way is only one of as many as an estimated 200 billion (2×1011)[1] to 2 trillion (2×1012) or more galaxies[2][3] (containing more stars than all the grains of sand on planet Earth),[4] proving Curtis the more accurate party in the debate.
  • Wikipedia, Great Debate (astronomy)
  • Hubble's findings fundamentally changed the scientific view of the universe. Supporters state that Hubble's discovery of nebulae outside of our galaxy helped pave the way for future astronomers.
  • Wikipedia, Edwin Hubble
  • The Andromeda Galaxy
  • Other stars have planets orbiting them
  • On 9 January 1992, radio astronomers Aleksander Wolszczan and Dale Frail carried out astronomical observations from the Arecibo Observatory in Puerto Rico which led them to the discovery of the pulsar PSR B1257+12 in 1990. They showed in 1992 that the pulsar was orbited by two planets. The data analysis gathered thanks to the discovery showed that two planets with mass 3.4 and 2.8 times that of Earth’s mass orbit the pulsar. The radii of their orbits are 0.36 and 0.47 AU respectively. This was the first confirmed discovery of planets outside the Solar System
  • Wikipedia, Exoplanets

Too small

  • The forces that control this world, like surface tension, are too small for us to pay much attention to in our day to day lives.
  • However, if you were an animal that lived in this world, they would be more important than gravity.



Football Jersey




Needle and thread




Bee stinger vs a needle. Note that it's not a hypodermic needle.


Tiny motion

The atomic

  • Richard Dawkins, Why the universe seems so strange
    • Science has taught us, against all intuition, that apparently solid things, like crystals and rocks, are really almost entirely composed of empty space. And the familiar illustration is the nucleus of an atom is a fly in the middle of a sports stadium and the next atom is in the next sports stadium. So it would seem the hardest, solidest, densest rock is really almost entirely empty space, broken only by tiny particles so widely spaced they shouldn't count. Why, then, do rocks look and feel solid and hard and impenetrable?
    • As an evolutionary biologist I'd say this: our brains have evolved to help us survive within the orders of magnitude of size and speed which our bodies operate at. We never evolved to navigate in the world of atoms. If we had, our brains probably would perceive rocks as full of empty space. Rocks feel hard and impenetrable to our hands precisely because objects like rocks and hands cannot penetrate each other. It's therefore useful for our brains to construct notions like "solidity" and "impenetrability," because such notions help us to navigate our bodies through the middle-sized world in which we have to navigate.

The tangle of molecules


Depiction of atoms


Too invisible

Air pressure

Air currents and pressure





  • Sound is just the vibration of things, which pushes the air, and it envelops the entire world in three dimensions. Waves upon waves, layered upon each other. #[[sr]]
  • It looks like ripples on an ocean.
  • Imagine being able to intentionally create these ripples, and have each wave in mathematical harmony with each other - this is what music is.
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  • CYMATICS: Science Vs. Music - Nigel Stanford GIF
  • Ruben's Tube
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  • You can see a video of music playing through the tube here.
  • A length of pipe is perforated along the top and sealed at both ends - one seal is attached to a small speaker or frequency generator, the other to a supply of a flammable gas (propane tank). The pipe is filled with the gas, and the gas leaking from the perforations is lit. If a suitable constant frequency is used, a standing wave can form within the tube. When the speaker is turned on, the standing wave will create points with oscillating (higher and lower) pressure and points with constant pressure (pressure nodes) along the tube. Where there is oscillating pressure due to the sound waves, less gas will escape from the perforations in the tube, and the flames will be lower at those points. At the pressure nodes, the flames are higher. At the end of the tube gas molecule velocity is zero and oscillating pressure is maximal, thus low flames are observed. It is possible to determine the wavelength from the flame minimum and maximum by simply measuring with a ruler.
  • Wikipedia, Ruben's tube

The Earth creates special conditions that we take for granted


The Earth’s gravity overpowers many forces

  • When in low gravity, some very different phenomena can happen than what we're used to, but this is actually the normal state of things! Down in the gravity well of Earth, they are overpowered by gravity and we'll go out whole lives down here without seeing them.
  • For example, if you wipe down a knitting needle with a cloth to charge it, and squirt some water droplets next to it, the water droplets will be attracted to the opposite charge and will start to orbit the knitting needle!

Radiation shielding

  • Radiation is more or less constant in space. On Earth, we're shielded by the magnetosphere and the atmosphere.
  • The rest of space gets blasted constantly by cosmic radiation (some of which originate from far-off supernovae, and some of which originate from a source that we have not yet discovered), and periodically by solar winds, which are particles flung into space from storms on the surface of the sun.

Too abstract

  • We have difficulty in perceiving large numbers.
  • At certain moments, our methods of description, like finding that stars number in the billions may be accurate but we can lose an emotional connection to what they represent. This is a failure of communication that must be addressed.
  • Around one billion minutes ago, Jesus was alive. That's how many one billion is!

Too complex

  • We do not perceive the depth and complexity that's underneath our lives.
  • 1. The universe
  • 2. Nature
  • 3. Our own bodies
  • 4. The economy and country we live in
  • 5. How any of the gadgets we use every day came to be
  • 6. Our own relationships

In the past or future

We only have fragments of history, and imperfect memory of our own lives.