Uncertainty is a genuine characteristic of work that originates from hazards, from unexpected or unforeseen events, from variations in the conditions of work or even from the doubt that the worker may have about the relevance of his/her own actions.
In this paper, these different facets are illustrated with various examples taken from manual labour to process control. By the way, some cognitive tools designed for the management of uncertainty are evoked. In particular, if problem solving seems to be a powerful device to cope with incertainty, it is stressed that workers tend to anticipate events rather than to react to them.
Overall, uncertainty reveals often the human adaptability to his environment, even though it may generate sporadically disturbances and failures. It is also emphasized that the human ability to cope with incertainty is strongly dependent on the way that work is organized.