Could balance be considered a sixth sense?
In short, your friend is being overly rigid in clinging to an ancient, arbitrary definition of what a “sense” is. I suggest you cease this friendship immediately. However, if you insist on keeping ties with this so called “friend,” perhaps this will help: The primary organ of balance (equilibrium) in the human body is located in the inner ear. The fluid-filled inner ear serves as both the sense organ for spatial orientation and head movement, as well as hearing. The inner ear is the body’s gyroscope, telling the brain at all times where the head is in space. The balance portion of the inner ear is referred to as the labyrinth or vestibular system. It consists of three semi-circular canals, and other structures in each ear. It is the movement of the fluid through these canals which constantly informs the brain as to the direction and the speed at which the head is moving in. This is why you get carsick: your eyes
This was a question on QI quite a while back. From the QI forums, a producer of the show responds: Aristotle proposed five senses: sight, hearing, taste, smell, and touch. Modern physiologists subdivide the “touch” category into “tacticion”, the sense of pressure perception, which is really what Aristotle was talking about, but also “thermoception”, the sense of heat, “nociception”, the perception of pain, and “equilibrioception”, the perception of balance. Some add “proprioception”, the perception of body awareness (eg if you close your eyes and move your hand about you continue to know where it is even though it isn’t being perceived by any of the traditional senses). There are other candidates, eg the senses of hunger and thirst, and direction, so that the number suggested varies between 9 and 21. There are also senses which some animals have but we don’t: “electroception” detects electric fields, “magnetoception” de
