Document Type : Research Paper



Before emerging of the modern logic, the then current logical system seemed to be without any alternative. But now classical logic encounters several systems which claim to be logical systems and rival of classical logic. Therefore a philosophical question arises: Is pluralism in logical system and/or logical rules possible? Contemporary philosophers give various answers to this question. Many don’t accept this possibility but their reasons are different. Past philosophers and logicians didn’t answer explicitly to this question, but by using their work we can gather that if they had been asked about this question they would have given decisive negative answer to it. In this paper I try to show that they were realist about logic and consider logical truths and rules as "secondary intelligible" (in a broader sense of this term).