Conclusion

Abstract

Arnold Sommerfeld’s approach to quantum problems displays twists and turns that do not follow a common trend. Quantum theory appeared intermittently and in different guises as Sommerfeld developed his institute into a “nursery” of theoretical physics. Nevertheless, the choice of themes and methods was not arbitrary. There was a marked preference for solving problems amenable to the skilled use of mathematical tools. Agreement with empirical results was considered more important than adherence to principles. This attitude was perfectly suited to accommodating quantum theory as a research subject of his school when physics underwent a period of rapid change.