The rapid industrial, political and economic progress in 19th-century Europe and North America was, however, paralleled by a sustained discussion about increasing rates of crime, insanity, vagrancy, prostitution, and so forth. Confronted with this apparent paradox, evolutionary scientists, criminal anthropologists and psychiatrists postulated that civilization and scientific progress could be a cause of physical and social pathology as much as a defense against it. This led to the emergence of a general theory of degeneration, never reduced to a concrete, simple theory or axiom. Instead, the concept of degeneration was produced and refined within and between several discourses, including the human sciences, the natural sciences, fictional narratives and socio-political commentaries. A broad outline of the theory, however, can be formulated, and it runs as follows.