The Quantum Theory

From a statistical point of view the theory of quanta introduced a revolutionary view of the statistics of radiation energy, still unrecognized as such. It took advantage of a relationship between two descriptors related to energy, namely its mean and its variance. That relationship came to be explicitly recognized in theoretical statistics only as late as the second half of the 20th century. It helps us in understanding that quantization is first and foremost an approach of statistics, which is needed in physics. The meaning of that approach is discussed, and then it is shown that it has deep implications in theoretical physics, still to be considered.