1 9 8 D O C U M E N T 1 8 2 J A N U A R Y 1 9 2 6 frequent transitions or does not.[3] Should one believe in a fixing of some phase here for a quantum jump, effected by one of these counter-running waves and should one assume that for atoms the [quantum] jump will immediately be re- versed again by the oppositely directed counterphase wave, but not so for the atom? If one does not want this, then there is no other alternative to regarding the transition probabilities themselves as dependent on the waves, which differ from the relative phases and which are simultaneously incident from various directions. But then, which fundamental determinants of the radiation should the transition probabilities refer to? Surely to a quantity characteristic of the whole coherent act of radiation that the atom undergoes? Therefore, either to a radiation intensity in the freely moving light wave impinging on the mirror or, more drastically, to an in- dividual act of emission within the effective light source? Classically, this referencing would correspond to the process by which one is initially able to derive the reciprocities in emission and absorption, namely, by ob- servation of the interaction between two coordinates of arbitrarily many coordi- nates linked together in an existing system undergoing periodic processes (Rayleigh’s reciprocity theorems).[4] Then, in applying this to Wiener’s case, for inst., reciprocity would exist between the probability of the absorption of one quantum emitted from a light-emitting atom A upon transition , and from a light-emitting atom B of the sensitive layer upon transition , and the inverse probability [---] of a transition . Schematically: ↓ = Likewise for negative irradiation: ↓ = Finally, likewise for the equivalence between : ↓ = ↓ und = (The probability of the primary transitions should be independently given, how- ever.) In such complicated interactions, the transfers of momentum are a very hard nut to crack it is actually not plausible that the layer atom B should emit impulses in λ 2 -- - λ 4 -- - S* S → λ 4 -- - Z Z* → S* S → Z* Z → S* S → S* S → ↓ Z* Z → Z* Z → S* S → S* S → ↓ Z* Z → Z* Z → b+ und b– S* S → S* S → S* S → S* S → ↓ ↓ Z* Z → Z* Z → Z* Z → Z* Z →