There undoubtedly is a real world out there, but our perception of it is limited. Natural selection has insured that any part of our sensory equipment that meets the criterion of costly-but-not-useful is quickly weeded out. At the same time, it cannot insure that everything of value appears and is preserved.
Because we are so attuned to our environment through our senses, we often don't realize that we don't just record—we actively interpret. Take taste, for example. Most of us find bitterness disagreeable and avoid it when possible. Yet bitterness is merely how we interpret certain chemical compounds often associated with poisonous plants, and we have evolved a sense of repugnance toward the taste involved. In a very real sense, bitterness is a thing of our brains, not of the chemicals.
As a perhaps clearer example, we've all seen dogs roll happily in
carrion that nauseates us. What could be more evident than the fact that the same
scents are interpreted very differently by us and, once he smells doggy again,
man's best friend.
Contributor: Arthur H. Harris, Laboratory for Environmental Biology, Centennial Museum, University of Texas at El Paso.
Desert Diary is a joint production of the Centennial Museum and KTEP National Public Radio at the University of Texas at El Paso.