Some comments on science:
Well, of course science doesn't always throw away anything it had learned/discovered before if a new theory arises. And very often the new is based on the old.
BUT this is not like building a house or a complex software, always adding a new layer which. It is more like exploring a complex landscape: the facts (trees, statues, rivers) are always the same, only the perspecive changes.
A new theory has (also) to explain old facts. Sometimes, there are more than one theory to explain the observed facts (think of Darwin and Lamarck, for example). In this case, new facts have to be sought. In my example, the way genetics work have been a fact to support Darwins theory.
And, ground level science: A theory can never be proven, it can only be falsified.
If a theory can't be falsified for some time, people/scientists get more confidence in this theory. But one, only one fact/experiment that can be explained by the corresponding theory, and the theory is falsified. It then has to be modified (think of the very complex arrangement of spheres to adjust the Aristotelan view of the cosmos to the observations of the movements of stars and planets) or replaced (Kepler/Galilei).
At least, this is how it is supposed to work. But people being people (and scientist even more so), change isn't always easyly greeted or accepted.
Jens
