All that is needed, then, is to place a supervisor in a central tower and to shut up in each cell a madman, a patient, a condemned man, a worker or a schoolboy. By the effect of backlighting, one can observe from the tower, standing out precisely against the light, the small captive shadows in the cells of the periphery. They are like so many cages, so many small theatres, in which each actor is alone, perfectly individualized and constantly visible. The panoptic mechanism arranges spatial unities that make it possible to see con-stantly and to recognize immediately. Full lighting and the eye of a supervisor capture better than darkness, which ultimately protected.
Visibility is a trap.
And this invisibility is a guarantee of order. The crowd, a compact mass, a locus of multiple exchanges, individualities merging together, a collective effect, is abolished and replaced by a collection of separated individualities. In view of this, Bentham laid down the principle that power should be visible and unverifiable. It is an important mechanism, for it automatizes and disindividualizes power. The ceremonies, the rituals, the marks by which the sovereign's surplus power was manifested are useless.