What is the basis of the wealth of nations ? Many thinkers tend to priviledge material explanations. As to Alain Peyrefitte, his hypothesis is that mentalities and behavior constitute the main factor of development.Through a vast re-reading of the history of western Christianity, from the 15th to the 18th century, Alain Peyrefitte shows that in Europe there has been an ethos of trust , that is a disposition of the mind in favour of innovation, which allowed the progressive institution of the free spreading of people, goods and ideas.