The humanoids of Galafray are in many ways just like us. Their sense perception, however, is very different.
For example, light reflected in the frequency range of the spectrum visible to humans is smelled by the Galafrains. What we see as blue, they sniff as citrus. Also, what we hear, they see. Beethoven’s Ninth Symphony is for them a silent psychedelic light show of breathtaking beauty. The only things they hear are thoughts: their own and those of others. Taste is the preserve of the eyes. Their best art galleries are praised for their deliciousness.
They do not have the sense of touch, but they do have another sense we lack, called mulst. It detects movement and is perceived through the joints. It is as impossible for us to imagine mulst as it is for Galafrains to imagine touch.
When humans first heard about this strange race, it did not take long for someone to ask: when a tree falls in a forest on Galafray, does it make a noise? At the same time, on Galafray they were asking: when a film is shown on Earth, does it make a smell?
Source: A Treatise Concerning the Principles of Human Knowledge by George Berkeley (1710)
The conundrum ‘If a tree falls in a deserted forest, does it make a sound?’ is one of the oldest in philosophy. Because it has become so hackneyed, it is useful to be able to reconsider the problem from a new angle. Hence the curious question, ‘When a film is shown on Earth, does it make a smell?’ For, bizarre though it may sound, this question is just as pertinent as the classic one about the forest.
The puzzles arise from the realisation that how we perceive the world depends as much, if not more, on our constitutions as the world itself. It just so happens that airwaves of a certain frequency are translated by our brains into sounds. Dogs hear things that we do not, and there is no logical reason why other creatures couldn’t translate these same waves into smells, tactility or colours. Indeed, synesthesia – sensory crossover, in which colours are heard or sounds seen – occurs in humans either permanently as a rare condition or temporarily, induced by hallucinogenic drugs such as LSD.
Given these plain facts, the question arises as to whether such things as sounds exist in the absence of creatures who hear. It is certainly the case that the air vibrates when a tree falls in an empty forest. But if sounds are in the ears of the hearers, isn’t it the case that with no ears there are no sounds?
If you want to resist this conclusion and say that when a tree falls on Galafray it does make a sound, surely you also have to say that, by the same logic, when a film is shown on Earth, it does make a smell. For to say the tree makes a sound does not mean that anyone hears anything. It can only mean that events occur such that, if a person were present, they would hear a sound. And that is enough to justify the claim that there is therefore a sound made. But if this is true, why isn’t it also the case that films smell? This is not the claim that when the film is shown anyone smells anything. All it means is that, if a person who smelled what we saw were present, they would smell the film. That seems to be as true as the claim that, if a human were in the Galafrayan forest when the tree fell, they would hear something.
This line of reasoning would seem to lead to the absurd conclusion that the world is filled with noises no one hears, colours no one sees, flavours no one tastes, textures no one feels, as well as a host of other sense experiences we cannot even imagine. For there is no end to the ways in which creatures might possibly perceive the world.
See also
| 21. | Land of the Epiphens |
| 28. | Nightmare scenario |
| 59. | The eyes have it |
| 73. | Being a bat |