  On the other hand, Weyl’s (1931b) discussion of the problem of  ‘directional quantization’ in the old quantum theory and  of the way that this problem is ‘resolved’ in the new  quantum theory appears to have a distinctly instrumentalist flavour.  In a number of places, he describes the essence of the dilemma posed  by quantum mechanics with a dispassionate precision. Consider, for  example, the following (Weyl, 1931b, 2 edn, 67): 