 The first formal paraconsistent logic to have been developed was discussive (or discursive) logic by the Polish logician Jaśkowski (1948). The thought behind discussive logic is that, in a discourse, each participant puts forward some information, beliefs or opinions. Each assertion is true according to the participant who puts it forward in a discourse. But what is true in a discourse on whole is the sum of assertions put forward by participants. Each participant’s opinions may be self-consistent, yet may be inconsistent with those of others. Jaśkowski formalised this idea in the form of discussive logic.