Scientists use the word "theory" in a slightly different way than lay people do: any proposition that cannot be demonstrated in a replicable experiment has to be forever classified as "theory", no matter how strong the evidence supporting it is. This is a little hard on some theories: it is a little bit difficult, for example, to contrive a replicable experiment to confirm the theory of plate tectonics.
As has been pointed out, the evolution debate is actually composed of two different propositions: Evolution, the facts behind which are practically incontestable, and Natural Selection, the theory which has been proposed to explain Evolution, which remains incomplete.
As far as teaching them goes, I think that when students are old enough to study the scientific method, and the various definitions of scientific law, scientific theory, and experimental evidence, it makes sense to introduce the concept of theory as incomplete and malleable. Before that point, I see no problem with teaching generally accepted theory as fact, especially since refusing to do that would make scientific education in the early grades almost impossible. |
