The Limits of Human Perception: Boundaries of Perception

Herein I will describe the limits of human sense perception for which I term the boundaries of perception. Humans have a finite range of perception from different sense stimulus in our environment, and this range is dependent on the sense and the environment itself. I will first begin by describing the senses and how they work on a physical level. I will then go on to describe how these senses are limited by the specific sense, the physical environment, and our current physical and mental state. Finally, I will finish with the idea of extending our senses with something like an extended mind and the idea of metasensation.
Humans have senses based on physical parameters
Humans are beings that perceive different experiences through the senses. Each waking morning, we begin to gain sense experience of our surroundings – we see the ceiling above our bed, hear the birds chirping outside or our pets running around, smell the coffee our partner made, feel the warmth and softness of our bed sheets. We have in essence 5 external senses – vision, audition (hearing), olfaction (smell), gustation (taste), and somatosense (touch).
Each sense is based on some physical parameter, and each parameter has limitations on which it is derived from. Vision is based on the photons of light reaching our retinas; hearing is based on the changes in pressure from air molecules vibrating the tympanic membrane; smell is derived from the concentration of molecular species reaching our olfactory receptors (smell receptors); taste based on the molecular species reaching our gustatory calyculi (taste buds); and touch on the changes in pressure to our somatosensory (touch) receptors just under our skin. Each one of these senses uses different forms of energy to transduce that energy into nerve impulses which we then feel as a sensation.
For our sense of sight we rely on photons, or light waves. Light waves travel infinitely in direct straight lines until they are reflected or absorbed. Any physical object has the potential to reflect, refract, or absorb light waves which alter the path of that light wave. Light waves travel forever and do not lose any energy, assuming there’s nothing in its path.
Things look larger close up and smaller at a distance due to the relation of the angle of light waves emanating from the object in relation to our eye. Things can appear invisible if they are too far away (as the light rays’ angles is so small that they are not picked up sufficiently by our retina), or if those light rays are blocked by other objects in which the light rays are absorbed or reflected from their initial path.
For our sense of hearing, we rely on the wave movement air molecules through a dance of expansion and rarefaction. The energy in the wave can also be reflected or absorbed based on the materials they come into contact with (e.g. soundproofing material can absorb all sound). Sounds move outward in a sphere from their location of origin and lose power the farther they move from their source. The loss of power over time is due to the friction and passive energy loss when transferring the energy from air molecule to air molecule. Sounds fade and become slightly distorted as they move from the source of origin as the amount of energy fades. The farther the distance from a sound source to us, or if there are objects absorbing or reflecting the sound waves we can insufficiently detect any sounds, similar to how sight works.
For smell, the concentration and type of scent molecules in the air is the driving force. When the concentration of a specific molecular species reach a certain threshold, our scent receptors make changes as the molecules bind, and neural impulses produce the experience of molecular species X. If the concentration is too low, then no changes are made to the receptor, or less receptors are changed and the force of the neural impulse is lessened (we smell things less strongly). Gases drop in concentration as they move from their source, and move outwards uniformly from their source. The farther the molecules travel, the less concentration they have as the same amount of molecules need to fill up a larger space, and the less we can smell it until a scent threshold is reached and we no longer can smell the scent.
Taste occurs when specific molecules reach our taste receptors, causing molecular changes in these receptors and sending neural impulses we interpret as “taste”. e.g. taste receptors can detect acidic molecules, for which give us that famed “sour” taste, like the citric acid from lemons.
Taste mostly comes from the concentration of molecules in solids, or liquids, but also within air as vapor droplets that drop on our tongue. Mostly, taste comes from liquids or solids that physically touch our tongues.
Touch comes from the direct specific pressure that activate touch receptors throughout our skin. Touch only comes from physical touch from solid objects, or liquid or gases at higher pressure – such as a stream of water or pressurized air – that apply enough pressure on our skin.
We also have temperature sensing receptors which make up a part of our sense of touch, as well as chemical sensors, or chemoreceptors. Chemoreceptors behave kind of like taste receptors in which specific molecules activate receptors, although the neural impulses give us a sensation of pain or burning, rather than taste sensation.
Limits of sense
Each sense works in a different way and has limits. Sight and sound have the longest range, followed by smell, then taste, and finally by touch. I am unable to see or hear anything on the other side of the world, or even in the apartment next to mine (assuming soundproofed walls and no windows). It’s impossible to smell things inside an airtight jar. In most situations can’t taste or feel anything not directly in contact with my tongue or skin (exception: invisible vapor droplets or mist). Our sense is limited depending on the sense, and can be said to be bounded or have a boundary.
The nature of the physical parameter each sense is based from also limits the eye can perceive. Humans can’t see colors outside the visible spectrum (the human eye can detect wavelengths anywhere from 380-740 nm – light waves higher or lower in energy can’t be seen) and no normal human can hear things below 12Hz and above 28,000 Hz. We can’t see things smaller than 0.1mm long. We can’t detect touch pressures under a certain threshold.

Boundary of Perception
The boundary of sense depends completely on the sense and the environment. For instance, I can’t taste, smell, or touch anything on the other side of a glass pane, but I can easily see it, and perhaps hear it. I can smell something inside a non-airtight opaque container, but can’t see it.
I call this limit to the senses a boundary of perception. The boundaries of perception are basically the lengths to which we can perceive sense info, in a spatial sense. This boundary is completely dependent on the environment, and certain environments bound our senses, and thus our perceptive abilities. A boundary of perception is the physical distance limit to which we can perceive something in our environment.
For instance, if I am in a small padded room with no windows or opening in the walls, my boundary of perception is the walls of the room. I will not see, feel, smell, or hear anything outside the room. On the other end of the spectrum, If I am in a wide open plain outside with no trees, my boundary of perception may be several miles (for sight and sound, and maybe smell). Our physical environment limits our boundary of perception, but also our awareness and current physical state. e.g. If I have a cold my ears may be plugged and I may have a lessened ability to taste or smell.
We can imagine this boundary of perception kind of like a radar system. Most sense energy travels linearly or outwardly to reach us from a distance. Currently if I am in the city and scan the horizon, I am receiving light waves from the building in a frontal cone, and I see the buildings and lights. As I turn or move my gaze, I lose sight of some buildings and gain sight of new ones.
Boundary of perception is tied in with focus and awareness
Although the physical sense itself has limitation from the space it resides in, even if the physical info does reach any of our senses, we also need to transduce and interpret the info which we receive as neural impulses. The interpretation or conscious awareness of the stimuli in our environment depends on our mental state and we have processes that prevent overloading the brain with info.
Most humans focus on only on things for which help us reach or immediate and future goals. We filter out a lot of stimuli as we go about our day, and rightly so – consciousness is a single-threaded affair and there are a lot of stimuli. We can only focus on one thing at a time (even though we can switch between things very, very quickly), and we will be overwhelmed if we try to focus on everything all at once. Our brain filters out things and we fall prey to things such as change blindness or inattentional blindness.
It’s possible to extend our boundary of perception through will. Our perception is tied in with focus and awareness, and shifting our current focus to things around us can make us aware of things we didn’t noticed before. Through meditation or by guiding our attention, we can notice previously unnoticed stimuli and increase acuity of weak stimuli.
Imagine seeing a figure coming over a hill in the distance, the figure is small and blurry. Is it an animal, a man, a woman? You squint and focus more attentional power on the figure, and you notice it’s in fact a woman on the hill. You hear voices down the hall but can’t make out what they’re saying, your bounded by the distance and weakness of the stimuli. You close your eyes, tune out other stimuli, and focus solely on the voices. You begin to stretch the boundary further and making it more sensitive to this stimuli until you can just make out your words. You just increased your boundary of perception through will.
In another sense, we can circumvent the phenomena of inattentional blindness by focusing our attention. Through focusing and guiding our attention and focus, we can notice things we didn’t prior. As I write these words, most of my current universe (or boundary of perception) is this screen, the words, and the ideas I perceive in my head. If I stretch my perception, I notice the table, the plant beside me, the noises coming from outside, the painting on the wall, and the feeling of the seat underneath me. In my focused writing state, my boundary was quite small, but can be stretched through will. In sum, our current state affects our current boundary of perception.
Definitional boundary of perception
Although I mention the boundary of perception as being heavily dependent on a person’s current state, I’d like to define the boundary of perception as the true boundary limit is the range of things I can perceive if I were to focus my sense with full power. We do selectively limit our boundary in a metaphysical sense, but physically there is only one boundary. If I would focus on my sight as far as it can reach, that’s my visual boundary. If I focus all my attention on my hearing until the limit of my power, then that’s my boundary of perception for hearing. This boundary I define as the range limit of detecting any stimuli when all our attention and power is put into that sense.
Using tools to increase the boundary of perception
Humans sometimes use tools to help us detect things we can’t see using our native perceptual powers. Microscopes, telescopes, binoculars, hearing aids, drugs (yes, some drugs have effects on perception and perceptual filtering). This increases our range that things can be detected. Normally, a human can’t detect a microbe, and they are bounded by the size of the stimuli. Microbes are just too small for us to notice with the naked eye, the light waves they put out are much too little and the they don’t sufficiently stimulate our retina to be noticed, and the angles of the light waves are just not right. Using optics, we can magnify and alter the light waves so they focus on a larger part of the retina, allowing us to break perceptual boundaries. Similarly with distant objects, telescopes and binoculars change the angle of distant objects so they appear larger. Hearing aids pick up weak sound waves and amplify them so they have more force on our tympanic membrane. In essence, tools allow us to magnify weak stimuli so that they are more readily perceptible.
We could also argue that strategically placed cameras might be a tool one could use to increase their perceptual boundary. If I place cameras at the edges of my current visual boundary of perception, I can simply look at the screen the camera is displayed on to see further than I could before. That blurry figure on the horizon? The camera shows it’s a dog. Although we can synthetically extend or perceptual boundaries using technology, I see this as a pseudo-boundary increase (or metasensation) and is a sort of extended mind. It’s not a real increase in direct perception, but merely another filter with which we can receive sense info.
Wrapping up
We have five main physical senses – vision, audition, gustation, olfaction, somatosensation – which rely on the physical parameters of the sense info from which they are constituted. The sense perception we receive is dependent on the sense and the environment, some environments allowing some senses to prevail while others fail. Each sense has a limit, or boundary, which is limited by the type of sense, our current state, and the environment which bounds our sense perception within that boundary – nothing can be sensed passed the boundary. It’s possible to increase our boundary of perception through will or tools, leading to extending the mind or metasensation. Humans have a boundary to perception, as we are finite beings dependent on the physical laws of nature.