In grade school we are taught about the five: sight, hearing, smell, taste, touch. Upon further learning we see that there are several different types of touch, at least two different types of sensing happening in what we call sight, etc., plus balance and kinesthesia, though both being dependent on the inner ear maybe they should be considered the same thing.
This depends on how we define “sense” of course, whether it refers to how information is received or how it is processed or a some combination of both. I realize in some fields of study it is more important to set the definitions in a certain and uniform way, but I’m asking more from a general or philosophical perspective.
In discussions on this I find most people like to expand the number of senses beyond five for some of the reasons above and more. But what about reducing the number? We have two senses: when particles bump up against our nerves (which would cover all the touches, sight, hearing, balance, kinesthesia) and when particles are dissolved in mucus and then metabolized (covers taste and smell). What problems would I have with this theory, in a general sense, not in medical application or such?
Also, can we sense heat and cold in a vacuum? If I were to suspend my arm in a vacuum and bring an hot iron close to it would I feel the heat before the iron touches my skin as I would in a normal environment?
I don’t have a lot of answers for you. Your post made me realize that I don’t know much about how senses work. However, my first reaction to your post is that I wouldn’t call sight a sense that is stimulated “when particles bump up against our nerves.” I think of it more as “electromagnetic excitation” or something. IIRC, a pigment molecule absorbs a photon and undergoes a cis-to-trans isomerization. This shape change sets off a chemical cascade that eventually results in a signal along a nerve. This is very much unlike hearing, where there is an actual physical movement that starts the cascade that leads to a nerve signal.
For your last question, yes, you can feel heat and cold in a vacuum. Heat transfer can be conductive or radiative. Vacuum obviously won’t conduct heat very well, but the sun still warms the earth up nicely. Your skin that’s facing a camp fire feels hot because it’s getting warmed up by absorbed radiation from the fire. The temperature-sensing nerves in your skin just care if the skin is hot, not if the ambient temperature is hot.
What about proprioception? That is, the body’s ability to track where all of its parts are at any one time. It may sound elemental, but people can do it, and octopod can’t.
Touch: Superficial sensation, Pressure, Temperature, Pain, Proprioception Sight: Discrimination of light, the contrast of light and dark, brightness, perception of wavelength, depth. Hearing: perception of wavelength, volume, location of source in space and time Smell: Chemical receptors designed to fit specific molecules, when they are plugged the sense is activated, when they are fully plugged the neurons stop firing and we can no longer smell. Taste: Chemical and Temperature sense receptors on the tongue. Works in conjunction with smell to identify chemical signatures. Equilibrium The VestibuloCochlear nerve serves both hearing and Equilibrium, because the ear is the sense organ for both.
Proprioception is specifically related to the soma’s (Musculature) relationship to itself. The brain integrates the proprioceptive information from all the muscles with the special senses listed above in order to provide information about the body’s position in space and time. As not all sensory data is transmitted at the same speed, the integration works in a way sort of ballistically to calculate where we are based upon the most recent data from any particular input, constantly correcting with the new input.
My own stupid question: do we then detect as “heat” both E-M radiation in the wavelengths lower than visual light AND energy transferred through conduction? Aren’t those different things?
AFAIK, you detect “heat” when your skin heats up. It doesn’t matter how it heats up. You’re not detecting the incoming radiation or the hot air, you’re just detecting your hot skin.
I know there aren’t organs geared to these things, but there must be some reason we use those terms instead of some other descriptives.
I even wrote a paper that attempted to identify the “sense appeals” in the poem by Wlliam Cullen Bryant, Thanatopsis, with a big chunk of those appeals being to the Sense of Time. My instructor chastised my inclusion of “sense of time” as being ridiculous. I have hated that asshole ever since!
Sense of Humor and Sense of Duty would qualify as emotions.
The sense of time and sense of direction I would have thought of as integrated processes of the other senses, not so much senses on their own. Like when you combine the depth perception of the eyes and ears with the proprioceptive sense of velocity from equilibrium and muscle sense.
Pain and touch are seperate. In fact, pain itself is really two senses, more or less; an older, slower and less precise version that actually hurts, and a younger, faster and more precise version that tells you where you are damaged more exactly and doesn’t hurt.
As I understand it, that’s how the organ that senses phermones works, but not how normal scent works ( if it was, we’d be unable to scent artificial substances, since we wouldn’t have a receptor for them ). As I understand it, normal scent involves many receptors that react with different strengths to a particular molecule; this activation pattern is what the brain interpets as a particular scent.
I think you are talking about chronic vs acute pain. It is my understanding that the basic touch receptors are the ones that register immediate pain, by being damaged.
Humans don’t have phermones, as I was reamed once on this board for suggesting. There is a certain bacteria that releases a chemical scent on our skin when we sweat that releases something that may act similarly to phermones for us. This is something I heard once in my Anatomy Class, so I don’t have a cite for it. In my neurology class I was taught that this is how olfaction works. If you have a cite for another version, I would be happy to read it. As for synthetics, I would explain it as being able to activate existing receptors. There are some chemicals we have no receptors for thus cannot smell.
The jury is very much still out one whether humans have pheromones, but increasingly favouring the positive. More here if you are interested. Anyway you missed the point. Der Trihs was talking about how the vomeronasal organ works, not whethrr it works in humans specifically.
But people retain a sense of time regardless of any input from other senses. If that were not the case then a person with perfect pitch could neither produce nor detect pitch if they wer eisolated from other inputs. The world’s best drummer would be unable to keep beat in an isolation tank. And we know a person in total isolation will still exhibit regular 26 hour circadian rythms. The sense of time isn’t related to other senses as far as anyone can tell, it is completely intrinsic.
I have taken it as the ability to sense one’s environment, this would exclude kinesthesia which is internal, but would allow balance, which would be sensing gravity.
Its the “absorbing the photon” part that I would consider a “particle bumping up against a nerve” and thus activating it, thinking in terms of the rods and cones in our eyes as being so sensitive that they can detect individual photons of light bumping into them.
Hearing requires a physical movement to bend a hair cell in your ear. Rods and cones are not so sensitive that they can detect the tiny transfer of kinetic energy from an incoming photon. A photon is not a marble. Yes, it has kinetic energy, but that’s not what is getting detected. Vision requires a matching of photon energy with the energy spacing between two adequately overlapping wave functions. We’re talking about a macroscopic physical stimulus with hearing and a decidedly quantum-mechanical excitation with vision. The two do not equate.