From where comes a good scientific theory

Some if not most of the great scientific discoveries come out of correct or mistaken scientific theories. Kepler is an example of having a “scientific” theory about planets orbiting in Platonic “perfect” spheres. Then with data of Brahe Tycho, he illegally took possession of, the evidence proved otherwise. Circle happened to be a unique geometric form out of more general Ellipse. He was smart enough to drop his wrong theory, even if he invested into it a fortune. He have prepared a golden model of his “perfect” theory of planetary orbits, to present it to the Habsburg King. I wish many others (mainly politicians) would have his courage, to abjure wrong investments and start again from the scratch.

On the other hand there are many more known successful scientific theories, that became later scientific truths. What jumps to my mind is Mendeleev’s elements periodic, where he presupposed order in elements, including prediction of unknown elements.

Truth is scientific theory do has in itself element of faith, to be believed without support in evidence. And such a faith can be very dangerous and then has to be opposed. The main problem of human thought and philosophy is to separate the scientific theories with potentiality to become scientifically truth or false, while supported or rejected by experimental evidence, from the false and dangerous ones, (the most dangerous are mainly in social and political sciences). The most well known false “scientific” theory is Marxism, that pretended to predict social, economic, historical development. The resulting disaster of implication of this theory is well known. Other such false theory was endorsed by the Nazism, with pseudoscientific theory of eugenics that became the scientific base for policy of genocide.