During the late-nineteenth-century and twentieth-century period, intellectual leaders and writers were deeply influenced by the ideas of the English naturalist Charles Darwin, the German political philosopher Karl Marx, the Austrian neurologist and founder of psychoanalysis Sigmund Freud, and by a growing strict interpretation of the separation of church and state doctrine. This trend increased after World War II and was further intensified by what appeared to be changes in the nation's moral consensus in the late 1960s. Educators and others became wary of using the schools for moral education. More and more this was seen to be the province of the family and the church.