Structures of natural reasoning within functional dialogues

The aim of this paper is to describe and characterize some structural features of natural reasoning by analyzing a number of conversations held by operators during shift changeovers. During this work phase the operators have to cooperate in order to carry out the same process. This need to cooperate leads to dialogues and joint elaboration of information, especially when involving the reporting of a malfunction. Three dialogues observed at this work phase on two study sites (a paper mill and a nuclear power plant) are analyzed. These analyses show that the step by step follow-up of the operators' collective reasoning is feasible. They highlight that these reasonings are complex experimental and hypothetico-deductive reasonings. They are reasonings for action, that are elaborated as the conversation unfolds, and for which the operators do not always have the means of testing their hypotheses.