On the point of mental illness, Foucault is well known for his view on it (quoting from SEP):
>But, according to Foucault, the new idea that the mad were merely sick (“mentally” ill) and in need of medical treatment was not at all a clear improvement on earlier conceptions (e.g., the Renaissance idea that the mad were in contact with the mysterious forces of cosmic tragedy or the seventeenth-eighteenth-century view of madness as a renouncing of reason). Moreover, he argued that the alleged scientific neutrality of modern medical treatments of insanity are in fact covers for controlling challenges to conventional bourgeois morality. In short, Foucault argued that what was presented as an objective, incontrovertible scientific discovery (that madness is mental illness) was in fact the product of eminently questionable social and ethical commitments.
>But, according to Foucault, the new idea that the mad were merely sick (“mentally” ill) and in need of medical treatment was not at all a clear improvement on earlier conceptions (e.g., the Renaissance idea that the mad were in contact with the mysterious forces of cosmic tragedy or the seventeenth-eighteenth-century view of madness as a renouncing of reason). Moreover, he argued that the alleged scientific neutrality of modern medical treatments of insanity are in fact covers for controlling challenges to conventional bourgeois morality. In short, Foucault argued that what was presented as an objective, incontrovertible scientific discovery (that madness is mental illness) was in fact the product of eminently questionable social and ethical commitments.