title: [Darwin after 100 years. 1983].
abstract: The triumph of Darwinism, together with the rise of Genetics, produced the virtual abandonment of the problem of form in Biology. The statement that any adaptive theory is tautological is however poor, the adaptation concept having an evident intuitive content. As in Geometrical Optics, a ray of light is, among the crowd of continuous curves uniting two points, the one requiring the minimum time for the light to go from one point to the other, so actual evolution, among the crowd of virtual evolutions between two forms, is the one best fitted to face 'selective pressure' in a given environment. The effect of selective pressure on the genome is unfortunately a merely theoretical not quantifiable concept. Most biological forms are forced by their internal stability to an essential fixity, so that the leap from one type-form to another should be abrupt-catastrophic. A good theory of evolution depends on a proper understanding of specific form stability. Biology must eventually return to the concept of ideal structure, the Goethian 'Urbild'.
authors.forename: René
authors.initials: R
authors.lastname: Thom
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Sermonit
mesh_terms: D000818:Animals; D005075:Biological Evolution; D001695:Biology / Q000266:history*; D049672:History, 19th Century; D049673:History, 20th Century; D049674:History, 21st Century; D016296:Mutagenesis