The size distribution of the domains of US-patented technological knowledge obeys an exponential law, revealing a disproportionable concentration of progress among larger domains. Our analyses suggest that this phenomenon is explained by a combination of two factors. First, domains' trajectories of growth have inherently different potentials. Second, differences in domains' potentials are magnified by a mechanism—domains' self-hybridization—endogenous to the process of knowledge growth. Our results show that in addition to being stable, the observed distribution of technological progress is likely to arise under very general condition
