Against the Freudian notion that we learn about health by studying pathology–both private and social, Foucault holds that studying resistance teaches us about power.
“I would like to suggest another way to go further toward a new economy of power relations, a way which is more empirical, more directly related to our present situation, and which implies more relations between theory and practice. It consists of taking the forms of resistance against different forms of power as a starting point. To use another metaphor, it consists of using this resistance as a chemical catalyst so as to bring to light power relations, locate their position, and find out their point of application and the methods used. Rather than analyzing power from the point of view of its internal rationality, it consists of analyzing power relations through the antagonism of strategies.
For example, to find out what our society means by sanity, perhaps we should investigate what is happening in the field of insanity. “