Sensation!

A random bit of jib-jabbery and general side tracking. The five senses seem to fall into two distinct categories. Those focused on interpreting biochemical stimuli (smell, taste) and those that interpret wave-based stimuli (sight, hearing). Touch on the other hand seems to be a somewhat different critter.

All of the above senses, hit our nervous system through specialized organs. Light bounces off objects at specific wavelengths, and we differentiate between color and shading based on the rod and cone structures which jangle alarm bells along the nervous system. Hearing filters in the vibration of atoms at particular frequencies in through the ear canal, beating a mad rhythm on the ear drum, and eventually tip toeing up a nerve. Sight and smell work in concert and run on larger bits and pieces of the world. Receptors accept particular kinds of structures and the cells of the receptors fire information back. Touch seems to have elements of both. Our sense of temperature is a product of picking up the motion of particles. But as a semi-permeable surface, compounds can penetrate the skin triggering nerves to fire. The presence of water molecules allows us to differentiate between wet (humid) vs. dry (arid) conditions perhaps? And how about chemical reactions at the skin level. If heavily basic or acidic materials come into contact with the skin the reactions trigger the nerves, but how would such be classified? It seems like the nerves themselves are much closer to the action when it comes to the sense of touch.