 In his AQT, Whitehead conceived of all electrons and protons as compositions of standing electromagnetic waves of charge density, which he called ‘primates’ or ‘primordial elements.’ In Science and the Modern World, Whitehead wrote: “We shall conceive each primordial element as a vibratory ebb and flow of an underlying energy, or activity” (1925 [1967: 35]). When a material atom emits energy, one of its composing standing electromagnetic waves is transformed into a travelling electromagnetic wave, that is, into light. The energy emitted by an atom is the energy of the emitted light, and the action of the emitted light is the product of its energy and its period (which is the inverse of its frequency). Experiment had revealed that the amounts of energy and action of atomic light emission do not form a continuous, but a discrete spectrum; they are quantized physical variables. In fact, a smallest amount of action exists, the quantum of action, given by Planck’s constant, and all measured amounts of action of atomic light emission are integer multiples of this quantum of action. Whitehead conceived of electrons and protons as composed of standing electromagnetic waves of which the action is also always a multiple of the quantum of action. And as he conceived of the atomic energy emission as a transformation of these standing into traveling electromagnetic waves, it became clear to him that this emission actually involves the decay of a primate, and that the loss of the primate’s quantized energy and action explains why the emitted light has similarly quantized energy and action.