 Logical falsifiability is a much weaker criterion than practical falsifiability. However, even logical falsifiability can create problems in practical demarcations. Popper once adopted the view that natural selection is not a proper scientific theory, arguing that it comes close to only saying that “survivors survive”, which is tautological. “Darwinism is not a testable scientific theory, but a metaphysical research program” (Popper 1976, 168). This statement has been criticized by evolutionary scientists who pointed out that it misrepresents evolution. The theory of natural selection has given rise to many predictions that have withstood tests both in field studies and in laboratory settings (Ruse 1977; 2000).