A new scientific truth does not triumph by convincing its opponents and making them see the light, but rather because its opponents eventually die, and a new generation grows up that is familiar with it.This does not conform to my experience in the biological sciences.
I think that what usually what happens is that a new way of thinking is promoted by well-established investigators. Gradually other scientists are convinced by the evidence to change their minds and the new scientific truth spreads within the community.
When a substantial number of scientists are converted, they start teaching the new concept in graduate and undergraduate courses. This produces a young generation who never heard of the old "truth."
If I'm correct then a new generation of scientists grows up familiar with the new scientific truth but only because the established scientists converted and started training the next generation properly.
When it comes to challenging old established concepts in a discipline I find that initially the younger scientists are often quite conservative unless they just happen to be working on that problem. This shouldn't be a surprise since our young investigators have their hands full just establishing themselves in their field. They don't have time to think about what's going on in the rest of the discipline. In fact, it might be detrimental to their careers to challenge most established concepts.
As I'm writing this I'm having trouble coming up with examples in biology. Most of the conceptual shifts that come to mind are ongoing controversies where it still isn't clear that the new scientific truth will replace the old one. I'm thinking of evo-devo, challenges to evolutionary theory, junk DNA, chemiosmotic theory, metabolism & thermodynamics, the tree of life, photosynthesis, and even new ways of teaching.
Can anyone think of examples were the shift has been completed so we can test the Max Planck hypothesis?
How about the shift from thinking that genes were proteins to genes are DNA?
