INTRODUCTION

Obligationes are a special, regimented kind of oral disputation involving two participants, known as opponent and respondent. Obligational disputations were an important topic for Latin medieval logicians in the thirteenth and especially fourteenth centuries (and beyond); indeed, most major fourteenth-century authors have written on obligationes. And yet, perhaps due to their highly regimented nature, modern interpreters have often described obligationes as ‘obscure’ and ‘puzzling’ (Stump 1982; Spade 2000). In what follows, we argue that there is nothing particularly mysterious about obligationes once they are placed in the broader context of an intellectual culture where disputations (of different kinds) occupied a prominent position. In effect, the inherent multi-agent character of obligationes must be taken seriously if one is to make sense of these theories.

In its best-known version, positio, opponent puts forward a first statement, the positum, which respondent must accept unless it is self-contradictory, thereby becoming ‘obligated’ towards it. (Typically, a positum is a false proposition.) Opponent then continues to put forward statements, the proposita, which respondent must concede, deny or doubt on the basis of specific rules. There were different versions of these rules, but according to the ‘standard’ approach, respondent ought to concede everything that follows from what he has granted so far together with the contradictories of what he has denied so far; and deny everything that is logically incompatible (inconsistent) with his previous actions and the commitments they generate. In the absence of such inferential relations with previous commitments, he should respond to a proposition on the basis of his own epistemic status towards it: concede it if he knows it to be true, deny it if he knows it to be false, and doubt those whose truth value he does not know (e.g. ‘The pope is sitting right now’). So rather than tracking truth, responses were above all guided by inferential, logical relations, since these relations took precedence over the truth values of propositions.

Obligationes are essentially adversarial exchanges, as participants have opposite goals: opponent seeks to force respondent to concede something contradictory, while respondent seeks to avoid granting something contradictory. The exchange ends when respondent fails to maintain consistency, or else when opponent says ‘time is up’, after respondent has been able to maintain consistency long enough.