In confrontation with doubt, Descartes realized that he could not be mad; the literary character of Rameau's nephew, however, knew that he was mad. The eighteenth century could not understand the work Rameau's Nephew. But a curious thing happened as the text was written. Unreason reappeared with a new power of interrogation. But the eighteenth century only noticed its social effects. For the first time since the Great Confinement, the madman became a social individual. For the first time, he was questioned. But yet madmen were only caricatures or silhouettes; their status is unsure. By letting madmen back into the light, classical reason admits its closeness to unreason. Reason allowed its double to drift onto the margins. But fear and anxiety were close. People were afraid of being confined. Confinement became a place of evil. A medical fear inspired by moral myth arose. People feared disease spread from houses of confinement. Houses of confinement were seen as sites of corruption and corrupted air, as with leprosy. The old fears about leprosy seemed to synthesize unreason and the medical universe. But the doctor entered the world of unreason as a guardian, not to decide who was mad or sane.
The eighteenth century reform movement aimed to organize and purify the houses of confinement. Morality and medicine tried to defend themselves against the dangers of confinement. The horrors confined in such places were fascinating, as de Sade's work shows. A whole imaginary landscape reappears, created by the great fear inspired by confinement. The classical period confined not only madmen and criminals, but also the fantastic. Fortresses of confinement separated reason from unreason on the surface, but also preserved places where they mixed. Confinement preserved forbidden imagery intact from the sixteenth to the nineteenth century. But in the darkness these images mutated.
In the classical period, awareness of madness and unreason had not separated from each other. Madness nearly disappeared in unreason. The fear of madness grew at the same time as the fear of unreason, so the two reinforced each other. Concern grows that man becomes more delicate as he perfects himself. Nervous diseases are growing. The threat of madness is ever-present. But the fear of madness is accompanied by an analysis of modernity, situating it in historical, social and cultural context. There is a difference between awareness of madness and unreason; from this point, awareness of unreason will become timeless and original, as in Nietzsche, whereas awareness of madness will situate it in historical context. The times of madness and unreason are different.
Foucault discusses madness and liberty. Montesquieu says that there is an English tendency toward suicide, which is brought on by their climate. A political and economic solution is being sought, in which progress and institutions explain madness. Madness is seen by other writers as the result of the liberty enjoyed in England. Liberty alienates man from himself and his world.
Religious belief prepares the ground for madness. It involves the satisfaction or repression of the passions. The organization of the believer's time by priests is beneficial. Old religion is a positive force, but modern religion eventually allows madness to function freely.
Civilization is the milieu suitable for the development of madness. The progress of knowledge allows a mania for study and a dangerous excitement of the mind to develop. Sensibility also detaches men from feeling; a sensibility that is controlled by the demands of social life is dangerous. Novels and theater excite people in a dangerous way. The novel perverts sensibility because it leads the soul into a world of imaginary sensibility.
The eighteenth century developed a new range of concepts around madness. In the sixteenth century, the secrecy of madness related it to sin and animality. In the eighteenth century, madness was situated in a place where man's relations to time, sentiment and other people were altered. Madness no longer related to nature or the fall of Adam and Eve but to a new order in which man had an idea of history, and in which the alienation of the physician and the philosopher operated.
Here, Foucault deals with the reorganization of the relationship between unreason and madness. Rameau's Nephew is a work by the French philosopher Denis Diderot (1713–1784), which represents the turbulent and romantic character of its protagonist in a dialogue with the author. Confinement still exists in the latter part of the classical period, but unreason reappears within it. This movement acknowledges the closeness of reason and unreason. As with Rameau's Nephew, the world debates and interrogates madmen to see if they knew hidden truths.
Fear developed at the same time, however. The fear of leprosy with which Foucault begins Madness and Civilization mutated into a fear of the whole structure of confinement, not just of the madman. The fact that they were partly fears of the diseases that madmen could transmit involved doctors in the process of confinement. Again, however, Foucault emphasizes that madness was not a medical matter. The doctor protected madmen and the public, but did not create or define madness in any way.
The reform movement that Foucault describes aimed to purify the place where madness was confined, just as earlier treatments tried to purify the madman's body. This was perhaps a good idea given squalid conditions of most houses of confinement at the time. Houses of confinement became reservoirs of disease, but also of imagery. Secret, hidden and dangerous things were locked away there. The Marquis de Sade, in whom Foucault took a particular interest, is a good example of this fantastic horror. He was a madman and a libertine, confined at his family's request, who recorded his violent, erotic fantasies in works such as 120 Days of Sodom. His private delirious discourse was eventually published; in this case, secret fantasies leaked out of confinement.
Unreason adopted fantastic forms. Foucault argues that confinement preserved such fantastic imagery by separating it from the world. Madness and unreason intertwine at this point; it becomes difficult to divide the two concepts. But madness increasingly becomes a cultural phenomenon, related to society, time and human lifestyles. The relationship between madness and civilization emerges as a theme, madness is related to external factors, and becomes a disease of society.
Montesquieu, the author of the famous eighteenth century work The Spirit of the Laws, established the link between politics and forms of government and external factors such as climate and geography. Foucault extends and develops this interpretation into a political and economic explanation of madness. He argues that Montesquieu represents the beginning of a theoretical approach to madness that sees it as dependent on the kind of society in which it exists. Religion is another social and economic factor influencing madness that was first recognized at this time.
Sensibility, meaning emotion or sensitivity, is an important eighteenth century idea. Foucault relates it to explanations of hysteria and nervous sensitivity; the "sensible" person essentially stimulated their nervous system too much. A key development according to Foucault is the creation of a link between inner, nervous sensitivity and external influences. Reading, watching too many plays and generally behaving in an inappropriate manner could lead to nervous collapse or madness. A new kind of moral disapproval was now possible; the madman's behavior could be blamed for his condition.
Foucault sees the development of new "causes" of madness as making a change in its status possible. Madness is now related to the world around the madman. Foucault's argument, developed in later sections, is that madness changed itself before the system of confinement altered.