A time of epistemic tension. The development of therapeutical tests in thecase of aids.

This article takes a look at the critical period in the development of ther apeutic tests on aids, marked by a number of public debates on the ethics a nd the methodology behind these tests. It shows the polarization of the spe cialist space (doctors, statisticians) with several testing philosophies. I t puts forward the opposition between two generations of doctor and statist ician; one, very attached to the public agency and more usually to medical research institutions, oriented towards a controlled design of medical scie nce and clinical practice, the other is engaged more rapidly in aids claimi ng a new form in the distribution of relationships between science and clin ical matters. The article specifies the structural position, in this space, of doctors who criticize globally the codified procedures which at present organize ethics and the scientific character of medical research. It shows what this period reveals about epistemic mutations in our societies and in contemporary medicine.