Michel Foucault (1926-84). Jacques Derrida (1976) and Julia Kristeva (1974) are the most influential figures in an intellectual movement known as post structuralism. However, it is the work of Foucault that influenced sociology and the social sciences. In his work, he illustrated shifts of understanding which separate thinking in the modern world from that of earlier ages.In his writings on crime, the body, madness and sexuality, Foucault analyzed the emergence of modern institutions such as prisons, hospitals and schools having played an increasing role in controlling and monitoring the social population. He wanted to show that there was 'another side' to Enlightenment ideas about individual liberty concerned with discipline and surveillance. Foucault advanced important ideas about the relationship between power, ideology and discourse in relation to modern organizational systems.
The study of power that relates to how individuals and groups achieve their end against those of others is of fundamental importance in sociology. Marx and Weber laid particular emphasis on power. Foucault continued some of the ideas they pioneered. The role of discourse is central to his thinking about power and control in society. He used the term to refer to ways of talking or thinking about particular subjects that are united by common assumptions. Foucault demonstrated the dramatic way in which discourses of madness changed from medieval times through to the present day. In the Middle Ages the insane were generally regarded as harmless; some believed that they might even have possessed a special 'gift' of perception. In modern societies, however, 'madness' has been shaped by a medicalized discourse, emphasizing illness and treatment. This medicalized discourse is supported and perpetuated by a highly developed and influential network of doctors, medical experts, hospitals, professional associations and medical journals.
Foucault states that power works through discourse to color popular attitudes towards phenomena such as crime, madness or sexuality. Expert discourses established by those with power or authority can often be countered only by competing expert discourses. In such a way, discourses can be used as a powerful tool to restrict alternative ways of thinking or speaking while knowledge becomes a force of control. Most of the Foucault's writings highlight the way power and knowledge are linked to technologies of surveillance, enforcement and discipline.
Foucault's radical new which characterized many of his early works, has become known as Foucault's archaeology' of knowledge. Foucault set about the task to make sense of the familiar by digging into the past. He energetically attacked the present the taken-far-granted concepts, beliefs and structures that are largely invisible precisely because they are familiar. For example, he explored how the notion of' sexuality has not always existed, but has been created through processes of social development. Foucault work on the assumptions behind current beliefs and practices to make the present 'visible' by accessing it from the past.