On Quanta

INSTEAD OF A "FESTSCHRIFT" In June 1998 Hans Primas turned 70 years old. Although he himself is not fond of jubilees and although he likes to play the decimal system of numbers down as contingent, this is nevertheless a suitable occasion to reflect on the professional work of one of the rare distinguished contempo- rary scientists who attach equal importance to experimental and theoretical and conceptual lines of research. Hans Primas interests have covered an enormous range: methods and instruments for nuclear magnetic resonance, theoretical chemistry, C* - and W* -algebraic formulations of quantum me- chanics, the measurement problem and its various implications, holism and realism in quantum theory, theory reduction, the work and personality of Wolfgang Pauli, as well as Jungian psychology. In many of these fields he provided important and original food for thought, in some cases going far beyond the everyday business in the scien- tific world. As is the case with other scientists who are conceptually inno- vative, Hans Primas is read more than he is quoted. His influence is due to his writings. Even with the current flood of publications, he still performs the miracle of having scientists eagerly awaiting his next publication.