It has been claimed by some philosophers of science that scientists give greater weight (or should give greater weight) to theories that make successful predictions of previously unknown facts, than to theories that only explain or deduce facts already known. Professor Brush is examining several historical case studies in order to find out whether scientists actually follow this rule, and more generally how the success or failure of predictions affects the reception of theories. Some possible case studies include Einstein's prediction of the gravitational bending of light; Alfven's predictions about the behavior of plasmas and electric and magnetic fields in the magnetosphere and interplanetary space, the prediction of the positron from Dirac's relativistic quantum mechanics, electromagnetic waves from Maxwell's theory, the prediction of the omega-minus particle from Gell- Mann's "eight-fold way" symmetry theory, Clairaut's prediction of the date when Halley's comet would return, and Mendeleev's prediction of new chemical elements to fill the gaps in his periodic table. The results of this research should help to clarify the reasons why scientists accept or reject theories.
