Apparently factual disagreement on the level at which selection operates often results from different interpretations of the term “selection”. Attempts to resolve terminological problems must come to grips with a dilemma: a narrow interpretation of “selection” may lead to a restricted view on evolution; a broader, less precise, definition may wrongly suggest that “selection” is the centre of a unified, integrated theory of evolution. Different concepts of selection, therefore, should carefully be kept apart.

Rosenberg has rightly argued that fitness is supervenient. But he has wrongly assumed that this makes “The fittest survive” nontautologous. Supervenience makes strict reduction impossible. It sheds light on disputes concerning the testability of evolutionary theory.

Grime in a recently developed theory distinguished three basic plant strategies: stress tolerance,ruderality and competition. He relates them to environments characterized in terms of stress and disturbance. Classifications of strategies and environments both are ultimately defined in terms of production. This tends to make the theory tautological. If the theory is to make sense, environments had better be defined in independent terms.