The ability to sense radiant heat on your skin.
A long time ago, I shaved my head bare- I went from having very long thick hippy locks to complete slaphead overnight. for a little while afterwards, I was able to ‘feel’ people walking by me or approaching me from behind by sensing the radiant heat from their bodies on my sensitive, newly-exposed scalp.
Which of my five senses was I exercising?
I would have to say touch. It’s just that you’re not touching a physical object, however the same nerves that tell you when you are touching a physical object are detecting the heat radiation, same as when you hold your hand near a gas fire or any radiant heat source.
Touch.
Heat sensing is part of the sense of touch, which has heat, pressure, and pain components.
I would say “touch”.
As you come into contact with things, it’s not just pressure your feeling. You sense the temperature, weight, and texture, pain, etc. I think all of these fall under “touching”.
In the case you describe, you’re only getting one of those inputs, but IMHO it’s still touch.
The reason that I was unsure is that, as a process, it’s a bit more like sight - sure, it’s nowhere near as sophisticated, but it’s essentially the same process; electromagnetic radiation is being directly sensed.
Wouldn’t there also be an argument for the case of normal sight itself just being a different sort of touch?
In evolutionary terms, didn’t ‘eyes’ start out as being extra sensitive patches of skin? I seem to remember reading that somewhere before.
If you were prepared to go that far then all senses are touch. Hearing is certainly touch since it’s detecting the movement of molecules against the eardrum in a very direct manner.
But the fact is that the ‘five senses’ idea is an historical one, not one based on any sort of science or objective reasoning. People x hundred years ago didn’t have the foggiest how the ears or eyes worked, much less what EMR was. So they simply divided sensation according to the organ that felt it. Ears = hearing, skin – touch, eyes = sights etc.
The five senses are no more logical or scientific than the four humours. Aside from the problem pointed out here that things like touch are really multiple unrelated senses there are numerous senses that aren’t included. Balance, proprioception, vomeronasal temporal perception and a great many more senses that indisputably exist but aren’t related to any of the traditional 5.
Simple answer: call it touch if you like. Call it thlabble if you like. It’s purely social convention with no objective meaning. I’m sure other cultures have other collections of senses.
Yes, eyes probably did get their start as light-sensitive skin patches. However, saying the ability to sense radiant heat is a form of sight is like saying hearing is a form of sight simply because it allows you to sense objects at a distance and determine somewhat their direction. Heat sensing, at least in humans, is not specific or focused enough, IMO, to qualifty as sight. Now pit vipers do have specialized sense organs for heat that might qualify as a form of “heat vision”, in fact the sense organs (the “pit” from which they get their name) are paired as eyes typically are.
An intriguing book on the evolution of sight is In the Blink of an Eye by Andrew Parker - he attributes the Cambrian Explosion to the development of sight. Has some interesting discussions on how sight differs from other senses, including such things as sonar which serve a similar function to sight.
They are believed to have been that according to some theories. Others suggest that there were always differentiated cells that made up the light receptive parts of the dermis right form the simplest organism, and that these became more concentrated in some areas giving rise to eyes.
I see what you’re saying, but there is a distinction with hearing in that it is a mechanical sensation - the detection of kinetic energy, whereas sight and the sensation of heat are both the detection of electromagnetic radiation.
This is where I beg to differ, at least weakly. When I had a shaven head, I was quite able to resolve the heat signature from the person’s head as separate, from their hands and discern that their hands were in motion, for example. It was very crude and prone to all sorts of interference from other heat sources, but there was definite detection of amplitude, direction and motion. Of course, my brain didn’t interpret the sense data as images, it was more the feeling of ‘something is shining on me from over there’.