2 5 2 D O C . 3 1 8 C R I S I S O F T H E O R E T I C A L P H Y S I C S ,. . . (1) which cannot be right because it produces an infinitely large value for the total den- sity of the cavity radiation . Planck found the expression corroborating all foregoing observations, in conformance with experience:[11] ,. . . (2) where k means a constant connected to the absolute size of atoms and h a natural constant hitherto unknown in physics, which one may well describe as the funda- mental constant of quantum theory. In 1900 Planck offered a theory for this formula that implicitly contains a hypothesis irreconcilable with physics up to that time, which we can retrospectively interpret, supported by the experimental and theoret- ical research of the past two decades. Wherever a sine-type oscillating process of frequency v exists in nature, its energy always carries an integral multiple of hv intermediate energy values do not occur in nature for sine-type oscillating pro- cesses. On the basis of this hypothesis it was possible to derive correctly not only Planck’s formula (2) of heat radiation but also the law of the specific heats of crys- talline solids.[12] But these derivations are all intrinsically contradictory: While making use of this new hypothesis they always rely on the foundations of classical physics, which is not compatible with it. Considering all the major advances that Maxwell’s electrodynamics and New- ton’s mechanics have made in physics and their present indispensability, one is obliged to doubt the basic hypothesis of quantum theory as much as possible. But phenomena do exist that directly confirm quantum theory even though its incom- patibility with the foundations of classical physics is immediately clear. The energy density of radiation emitted from a radiating source diminishes, according to Maxwell’s theory, with the reciprocal square of the distance. The energy available at one place for processes of absorption per unit time would thus have to diminish infinitely with distance. As, for ex., the chemical decomposition of a molecule or the release of an electron from an atom requires a definite amount of energy, similarly, radiation that has been sufficiently weakened by propagation away from the light source should no longer be capable of generating such a chem- ical process. Experience shows, on the contrary,[13] that the chemical and photo- electric effectiveness of the radiation is completely independent of its density the ρ αv 2 T = [p. 5] ρ vd v=0 v=∞ ρ 8πhv 3 c3 -------------- - 1 ekT hv ------ 1– ---------------- ⋅ = [p. 6]