Theories of European integration have faced criticism for being too narrow and time-bound, and for not being grounded enough in empirical evidence. In response, scholars have sought to develop more complex and nuanced theories that combine elements of different approaches, such as neofunctionalism, interdependence, and intergovernmentalism. Robert Keohane and Stanley Hoffmann's work is an example of this approach. Other scholars argue that a synthesizing approach is necessary to develop a comprehensive theory of integration that includes findings about state behavior, EU institutions, domestic politics, and wider contexts such as globalization and differentiation theory. The ultimate goal of grand theory remains unchanged: to provide insights into the integration process by offering partial explanations, promoting further research and thought, and influencing policy development.