The works of Foucault focus on an inter-relationship between power and knowledge using the methodology of what he terms Archaeology and Genealogy.
These methodologies dig out the historical conditions for various forms of knowledge. It is in this context that he develops the concept of epistemes, which when uncovered provide explanations for how knowledge became established as knowledge. For Foucault knowledge is power and power is knowledge and thus he brings into question the objectivity of knowledge itself. The human subject is de-centred in that subjectivity and volition are social constructions. This approach is not teleological, for Foucault history is not progressing towards some end, it is not progressive in any sense, therefore it is not assumed that one episteme is better than another- only that each episteme is dominated by different forms of knowing and therefore power is at different times concentrated in the hands of those who possess the knowledge. Power and knowledge are entangled and like Neitzche, Foucault sees a world in which there is a constant competition for power that will never be resolved, but that will and does generate changes in the way of knowing, changes in truths. Although knowledge is power, Foucault argues that power is an intrinsic part of the process of being an individual, it is not something from which mankind struggles to be emancipated from, but something that as an individual man seeks to use to define his individualism. In Madness and Civilisation Foucault uses madness as a method of critique of bourgeois reason in the capitalist system, he illustrates different discourses surrounding madness since the middle ages, in this episteme madness was regarded as a sign of Gods grace or anger- truth, knowledge and ergo power were of course concentrated in a supreme being , later during the renaissance period madness was associated with the wisdom of folly as illustrated by the ship of fools setting out on a journey of destiny. In the classical age madness became associated with illness due to laziness and bodily deterioration and was treated by a series of weird and often cruel treatments, which concentrated on restoration of morals to the afflicted individuals, thus stripping the insane of human dignity. It was the conversion of the asylum into a medical space that began to form the society of the insane into a microcosm of the values and morals based bourgeois society. This brought about social condemnation of the insane. The sane were moral and worked hard the insane were immoral and lazy.
Psychoanalysis transformed this picture of the asylum into a more medicalised version but only on the surface, deeper underlying analysis reveals that the expertise of the psychoanalyst himself has replaced the authority in whom expert knowledge is vested and thus, the psychoanalyst has merely transferred the power of the institution of the asylum to himself and his science. He has concentrated power in his discourse.
The birth of the clinic is an excellent example of Foucaults archaeological methods, and although it has been criticised as being very close to a structuralist approach, it exposes the birth of a powerful new discourse about the body and traces the development of the medical discourse from its infancy based on the individual as a balance of humours to a stage where humans are viewed as the sum of their constituent parts. The different ways of knowing about the body have allowed the medical profession to establish a discourse of expertise about human life and legitimised the states intrusion into even the minute of everyday life. Transferring surveillance from the sick body to the healthy body. Man has through the power of this discourse become a creature to be observed, to be studied and a creature for whom living is an endless series of risks. The medico-administrative society has legitimised surveillance of the individual and policing of the individual, thus illustrating that knowledge and in particular the ability to contribute to and have expertise in the language of expert discourses creates power. Think of the new discourse of terrorism and its implications for surveillance and the way in which this has been formed into laws for our protection and the rise in the politics of fear, thus allowing the state to exert greater social control over the individual citizens.