One way to dismiss an idea is to insist that it “is just a theory.” However, the point of calling something a theory is that it is a proven explanation. This doesn’t mean it cannot be changed, improved upon, surpassed by another theory that explains more and in better ways. When a concept is a theory, however, it sets the terms and relations necessary to improve or even overturn it.
Three examples of theories changing
The first is phlogiston. First introduced in the 17th century, this theory attempted to explain how things burn, and why they stop burning as well. Things which are liable to burn have a substance, the theory went, that escapes during the burning that it causes, until the air around it becomes full of this “phlogiston” (meaning “burning up”), thus stopping the fire. When this process happened slowly, it explained how rust formed. As a theoretical explanation, however, it got people thinking about how to prove it, or improve it. One fact that it could not explain was that, for instance, magnesium when burned weighs more than it did before being burned. Eventually Antoine Lavoisier proved that fire (and rust) are actually caused by oxygen, a substance not in the object being burned or rusting, but in the air. Rust is “oxygenation”, and fire is very rapid oxygenation.
