The Different Roles of Deduction in Communication

This article is concerned with a distinction between two epistemic roles that, according to Michael Dummett, deductively valid arguments could play in communication. This means the distinction between: a) arguments that purport to explain, and b) arguments that purport to persuade. The article is also concerned with a resulting shift in the appropriate approach to these roles of arguments. In this respect, for example, an idea emerges which traditionally any realistic-minded author would have automatically dismissed as unthinkable, but which is now relevant. This is the idea of circular justification of knowledge as something rationally acceptable. The distinction also leads us to the view that we do not need anyone to convince us that the rules of correct deduction are valid. In fact, we are already convinced of the validity of the forms of inference that guide us at the moment we think about the deductively valid arguments. There should consequently be no authentic context in which we need to be persuaded of their validity. The present article attempts to reflect critically on the distinction between the epistemic roles of arguments, and on the resulting shift in the methodology, by making four critical objections to its presentation.