[The calculation of probabilities as a basis for certainty in medicine].

Medicine underwent a serious crisis in the changeover from the 18th to the 19th century. Resorting to the calculation or probabilities as a means to providing Medicine with the desired precision and certainty was one of the most notable features of the remedies taken by doctors to emerge from this crisis. This resorting to the calculation of probabilities was very controversial and hotly debated at that time and we hope to show that this was indeed the case in France.