A common definition of science is "knowledge, as of facts or principles; knowledge gained by systematic study."
Science is never stable. There is always layer upon layer of detail that is waiting to be discovered. The "Standing on the Shoulders of Giants" is the underlying concept. Our level of scientific understanding is driven by our current understanding and our needs to go deeper. The knowledge can change and grow based on deeper systematic study.
In the middle ages, when transportation was limited to horse, cart and walking. The naivety of a geocentric university was sufficient for the time. And for the most part motion of planets was fairly accurately explained by epicycles. The "Science" of the age was sufficient. As travel and migration required more detailed knowledge, the science improved to explain what was seen. New models were formed, and tides, winds and so on became more accurate and combined into a deeper understanding.
The beauty of science is that as the foundations of one area is broken down and rebuilt, what replaces it must not only encompass what was there, but also link deeper into other areas that caused the original science to fail. It doesn't make the previous science and knowledge bad, just incorrect. One can't deny that a model that explained a known phenomena for that point in history was bad science.
In 40 years time*, we'll look back at the misguided fools at the start of 21st century and our futile and plain incorrect approaches to fusion. We may not be there, but we'll probably dealing with all sorts of funky and interesting materials on the way to get there.
Those of us who will have children should know that their science *will* be different in a lot of areas than our science. That is a good thing.
* Bonus points for replies that say why I chose the "40 years time".