Dialogue systems find more and more applications but the scientific improvements face difficulties to be transferred into the dialog technologies. France Telecom R&D is designing a new architecture based on uncertainty management in dialogue. Dialogue constraints lead to define a Logical Framework for Probabilistic Reasoning (LFPR) which results are close to the ones of the Evidence Theory and the Assumption-based Truth Maintenance System (ATMS). The paper eventually compares it to the Theory of Hints of Kohlas and Monney.