The germ theory of disease holds a key position in the evolution of medicine, with Robert Koch's criteria for determining the “cause” of disease a tipping point in modernization. Even though the seminal works of Pasteur and Lister on the developing germ theory preceded Koch's postulates by more than a decade, the simple logic behind his strategy, which required identification, isolation, and then transmission of the putative source of infection in order to prove causation, was enough to convince even marginally trained physicians of this era that medicine was indeed a scientific discipline. By making laboratory research fathomable to the clinician, Koch elevated clinical medicine to the rank of science.
Margo CE. From Robert Koch to Bradford HillChronic Infection and the Origins of Ocular Adnexal Cancers. Arch Ophthalmol. 2011;129(4):498-500. doi:10.1001/archophthalmol.2011.53