Foucault's discussion of animality and madness is contradictory and complex. He charts the move from fantastic images of madness in the Renaissance, to one in which the madman was part animal. Seeing madness as bestial justified treating the madman like a beast, but also offered a deeper explanation of his actions and place in the world. Rather than seeing animal qualities as being similar to those that human have, or seeing humans as highly developed animals, this attitude robs the madman of all humanity. By removing his humanity, madness makes the madman dangerously free. He cannot be bound by human laws, and so has to be confined.
Foucault's picture of animality as anti-nature is also confusing. The "animal" is not part of nature because the order of nature implies a rational order. In a way, the practices of confinement are justified by this conception of madness; they attempt to hide away this irrationality.
Foucault develops the relationship between madness and unreason further in this section. He needs to explain why madness is seen as different to the range of deviant behavior that is confined. He explains it in terms of religious change, adding another dimension to the economic and moral elements already discussed. Foucault argues that unreason and religious ecstasy were less important after the seventeenth century, which is commonly seen as a period of great religious enthusiasm. As religious enthusiasm declined, madness appeared to fill it place. In a sense, the Church needed the structure of madness to replace something it had lost; the parallel with the decline of leprosy is obvious. Explaining the Church's concern with madness in terms of kindness or Christian charity is meaningless to Foucault. What matters to him are changes in demand for certain figures or roles, such as the leper or the madman.
The reorganization of madness and unreason is a general theme of Madness and Civilization. In this section Foucault argues that the classical period confined a range of dangerous and liberated behavior, but that this unreason represented the only way of understanding madness. Madness and the way the mad were treated made sense only against a background fear of absolute liberty. Confining madness, Foucault argues, was the eighteenth century's way of dealing with this fear.