Suppositions in argumentative discussions: A pragma-dialectical solution for two puzzles concerning thought experimentation

The practice of constructing imaginary scenarios for the sake of argument is sometimes referred to as ‘thought experimentation.’ In this paper, I employ analytical tools from the pragma-dialectical theory of argumentation in order to clarify two theoretical puzzles that have been formulated with respect to thought experimentation. I do so by analysing the place and function of argumentative moves that contain suppositions in their propositional content. Three such moves are distinguished: proposing suppositions, accepting suppositions and using suppositions.