Continental drift is created at spreading centers, and this, along with subduction, drives the system of plates in a chaotic manner, resulting in continuous orogeny and areas of isostatic imbalance. The theory of plate tectonics explains all this, including the movement of the continents, better than Wegener's theory. Hans Stille and Leopold Kober opposed the idea of continental drift and worked on a "fixist" geosyncline model with Earth contraction playing a key role in the formation of orogens. Other geologists who opposed continental drift were Bailey Willis, Charles Schuchert, Rollin Chamberlin and Walther Bucher. In 1939 an international geological conference was held
Drift hypothesis at supported the drift hypothesis, but when he examined them, he found their conclusions were "based on assumptions and methods that lacked empirical support." Another statement in Fox's study was, in studies done on social class and mental illness, "identify drift as an individual's downward intergenerational social mobility after the onset of mental illness, rather than as residential drift from higher to lower class status areas". So depending on what one's definition of drift hypothesis is, there will be data either to support or refute the validity of it. From an economic perspective of social class and mental illness, the