The overarching project of any comparative biology is to explain the fit and diversity of organismal form. These are the consequences of evolution. The predominant approach to explaining evolution, ever since the Origin of Species, is 'variational.' Evolution occurs because of the standing variation in populations. The Modern Synthesis version of evolutionary explanation is not only variational, it is radically anti-individualistic; it accords virtually no explanatory role to the properties and process that occur within individuals. The anti-individualism of the modern Synthesis is now facing a battery of severe challenges. Increasingly, it is becoming apparent that the processes that occur within individuals are crucially involved in each of the component processes of evolution: development, inheritance, innovation, and adaptive change. Any comprehensive evolutionary theory must reserve a place for the ways in which the properties that make organisms organisms – their self-regulating, self-synthesising, purposiveness – figure in the evolution of organismal fit and diversity.