Sometime what we learn in school can be limiting, however. Especially things that we learn at a very young age and, for the remainder of our lives, believe to be true. When I was little I was also taught that there were "Nine planets"... that has been the topic of several astronomical discussions over the past 10 years or so, and it is clearly an issue of the actual definition of the word "planet". No one wants to add more planets to the "line-up" just because there's... only supposed to be nine!
You see what I'm saying, right? It's a social, sometimes psychological struggle to shift one's paradigm from believing one thing, to believing something different. Once a belief, or a fundamental understanding of something is ingrained into our minds, it can be VERY difficult to change that belief.
I believe that there are more than five senses. And before you go directly to the comments section for your rebuttal, hear me out. Again, this debate will lie in the definition of the word "sense" and whether or not each "sense" has a dedicated organ. But to me, a sense can be related to a "channel" for information input, not necessarily an organ.
Some other senses I believe that we, as a human race, have and should be exploring and encouraging are:
"Extra" Sensory Perception (ESP)
Echolocation - Obviously, this is the first one I'm going to discuss. As far as organs go, this sense uses primarily the ears, but I believe it also uses the nervous receptors in the skin as well ("touch"), as vibrations and pressures from sound can easily be felt on the skin.
Proprioception - This is the sense of the physical positioning of one's own body; joints, limbs, orientation, etc. We talk about this in depth in martial arts classes. If you close your eyes and move your arms around, you have the sense of where they are. It's an interesting sense and you can read more in this article on proprioception written by Bruce Lee's daughter, Shannon. Some people have been known to lose this sense due to brain injury or other trauma and it is completely debilitating.
Interoception - This is our sense of the physiological well-being of our bodies. It's how we sense our stress levels, our mood, disposition, etc.
Equilibrioception - Our sense of balance, called equilibrioception, makes use of our eyes, ears and sense of proprioception, above.
Altitude - When we have a head cold our ear drums generally are generally very sensitive and can even pick up on slight pressure changes due to altitude. A similar feeling can be experienced when scuba diving as the water pressure changes when you dive deeper. Didn't think you had a built in altimeter (or depth meter) did you?
ESP - An amazing sense that may be controversial and experienced differently by different people. I know I've experienced certain intuitions that I can't describe. I believe that information can be transmitted many other forms. What are your thoughts?
I think this list is probably the tip of the iceberg and if you can think of more, please post in the comments!
I think it would be best to teach children about the "Senses" as opposed to the "Five Senses". This would eliminate the psychological limitations for future generations. If a new sense, is discovered, or developed, it would be in our best interest as a species to teach and further develop that sense.