The number of writings appearing on Teilhard de Chardin is increasing daily, with the great majority of them treating his philosophical, theological or humanistic ideas. Discussion of his evolutionary theory from a more scientific point of view is relatively rare. For one thing, he seems to have leaned heavily, though not exclusively, on a neo-Lamarckian explanatory viewpoint. The major problem, however, is that he espoused a theory of evolution, orthogenesis, which is rejected by the majority of scientists today on the ground that there is no evidence for it. Many writers force one to conclude that they are unaware of the ramifications of holding a theory that is considered unviable in the scientific community. In the same vein, too many authors do not seem to take seriously the critics of Teilhard who have made this point, e.g., George G. Simpson, Peter Medawar and Theodosius Dobzhansky. One gets the impression that there is a wider gulf between “the two cultures” than he might have imagined. Little concern for Teilhard's orthogenetic evolution leads us to suspect that writers do not know that it makes a difference what type of evolution Teilhard espoused. There may be a cultural lag between science and the other disciplines, but orthogenesis has been around for many years now, and has been rejected by biologists for at least fifteen years, which is a conservative estimate.