Dr. Marjorie Grene has argued that criteria taken from a personalist philosophy of science have regulative force in the dispute between orthogenetic and synthetic or neo-Darwinian theories of evolution, and that these criteria commend the acceptance of the orthogenetic position. Grene's position includes two basically correct theses concerning the limitations of operationism and reductionism. However, she fails to show that personalist tenets are necessary for the validation of these two theses. Moreover, the proposed modifications of evolutionary theory depend upon additional (...) premisses: that biology must study individuals rather than populations, and that the synthetic theory must prove that natural selection and mutation are the only possible factors for control of the direction of evolutionary change. The evidence for these premisses is called into question. (shrink)