 Unlike some interpreters of the correspondence principle Darrigol does believe that there is a coherent and rational account of Bohr’s correspondence principle in terms of the intensity correspondence. He argues that Bohr is justified in calling it a law of quantum theory because “[i]t was indeed a relation between two quantum theoretical concepts: the probability of a quantum jump, and atomic motion” (Darrigol 1997, p. 553). Moreover, Darrigol cogently argues that this correspondence was incorporated directly into matrix mechanics in Heisenberg’s 1925 paper, thus vindicating Bohr’s claim that the new quantum mechanics can be regarded as “a precise formulation of the tendencies embodied in the correspondence principle” (Bohr 1925, p. 852; BCW 5, p. 280).