How many senses are there?
We are used to thinking that we have five senses. These are:
- Visual sense (sight)
- Auditory sense (hearing)
- Olfactory sense (smell)
- Gustatory sense (taste)
- Cutaneous sense (touch)
…but this represents quite a limited view of what the senses are, and the purposes they have. Some scientists say that sight, for example, is actually two different senses, as it involves both the detection of both colour and brightness. Just as we have a separate button on our TV remote control for both these things, so we have separate receptors in our eyes.
This debate partly depends on how we define what the senses actually are. If our senses are purely the means by which our body receives external stimulae (exteroceptive) for our brains to then interpret – as the OED says – then perhaps the list is complete. But if we define the senses as the means by which our body communicates to the mind both external and internal stimulae (interoceptive), then we could argue that there are at least three more senses, among them being:
- Kinesthetic sense (awareness of one’s own body movements and dimensions)
- Vestibular sense (balance)
- Organise sense (‘call of nature’, hunger, thirst, etc.)
Also, we are only talking here of human senses. If we are going to take that ‘s’ in ‘knowers’ at the centre of the TOK diagram seriously, perhaps we need to think about not just human perception, but that of animals as well. Think of bees, which can detect the magnetic field of the earth; bats, which use sonar for navigation; snakes, which can sense sound waves by using bones in their heads; chameleons, which can see in two different directions at the same time. Not only are we talking about senses that go far beyond the range of humans, we are also talking about extra senses.