What this recovery reveals is that even the most apparently 'superstitious' period still makes perfectly good sense of the world in its own kind of way. (In this respect, Foucault demonstrates for historically remote societies what Lévi-Strauss demonstrates for geographically remote societies.) And, conversely, even the most apparently 'scientific' period is still perfectly irrational about the world in its own kind of way. There is no decisive revolution from ideology to science – neither the long-term revolution envisaged in most histories of human thought, nor the all-at-once revolution envisaged by Althusser. There is simply a succession of different ideologies, some of which consider themselves 'scientific'. (If Foucault himself prefers to avoid the term 'ideology', this is mainly in order to avoid any suggestion that ideology is something false and something different to science.)
Foucault 's attitude to 'scientific' revolutions is clearly demonstrated in his account of the advent of modern medical science around the end of the eighteenth century. Ordinarily, we would think of this as a tr iumphant breakthrough from ignorance to truth. But Foucault presents it very differently. According to Foucault, the old 'superstitious' medicine made perfectly good sense of disease – but in terms of a discourse which has since been banished and forgotten. This discourse framed disease against a dominant assumption of life; and against a dominant assumption of life, disease showed up as a counter-life, an evil, a negative force. Disease was always the invisible 'other' of the visible human body. But in the new discourse emerging around the end of the eighteenth century, disease shows up not as a negative force but as a positive object – a positive object for a positivist science to study. Disease is no longer the invisible 'other' of the visible human body, but something visible in its own right inside the human body. It is no coincidence that the end of the eighteenth century also sees the emergence of pathological anatomy, the practice of opening up bodies in order to inspect disease actually within the organs. But this practice, of course, can only be carried out upon dead bodies. So in this respect, the new discourse frames disease
against a dominant assumption of death. As Foucault puts it: 'Disease breaks away from the metaphysic of evil, to which it had been related for centuries; and it finds in the visibility of death the full form in which its content appears in positive terms.'1 Even to think and speak about disease in terms of separate static internal organs presupposes death as 'the concrete a priori of medical experience'.