The 1900 rediscovery of Gregor Mendel's laws of inheritance is often cited as a turning point in biology, but it was also a moment of intense interdisciplinary conflict. Mendel had published his work on pea plants in 1866, but it remained largely ignored for decades because his mathematical approach was alien to the descriptive traditions of nineteenth-century botany. When Hugo de Vries, Carl Correns, and Erich von Tschermak independently arrived at similar conclusions at the turn of the century, the scientific community was forced to grapple with a new, particulate view of life. This led to a bitter feud between the Biometricians, who believed in continuous variation and used statistical tools to study entire populations, and the Mendelians, who focused on discrete traits passed through individual lineages. The Biometricians argued that Mendel's rules were merely a special case and could not explain the subtle, gradual changes required by Darwinian evolution. Conversely, the Mendelians argued that the laws of inheritance provided the very mechanism Darwin had lacked. The conflict was not resolved until the 1930s with the Modern Synthesis, which mathematically demonstrated that many discrete genes acting together could produce the continuous variation observed by Biometricians. This history shows that the acceptance of a new scientific theory depends not only on empirical evidence but also on the successful integration of different mathematical languages and research priorities.