Orthogenesis

Orthogenesis also known as orthogenetic evolution is an obsolete biological hypothesis that organisms have an innate tendency to evolve in a unilinear fashion due to some internal mechanism or "driving force".

American paleontologist George Gaylord Simpson (1953) in an attack on orthogenesis described it as "the mysterious inner force". Classic proponents of orthogenesis rejected the theory of natural selection as the organizing mechanism in evolution for a rectilinear model of directed evolution. The term orthogenesis was popularized by Theodor Eimer.