MODAL LOGIC BETWEEN TRADITIONNAL (ARISTOTLE, IBN SINA) AND CONTEMPORARY APPROACH
Aristotle founded the science of logic in order to control language source of fallacies and sophistry. He built his syllogistic on two basic principles: non-contradiction and the excluded middle. He distinguished between different types of statements: declarative and non-declarative, only the first type was used in syllogism´s theory, because it is a tool of demonstrative science. He divided them, declarative statement, into two categories: Assertorics, and modals (necessary, possible, contingent, impossible) which he encountered difficulties in his logical analysis, because it is out of frame two valued according to the two principles, such as propositions that occur in the future whose cannot be determined now. This kind of statement was also treated by the Muslims logicians, especially Ibn Sīnā who expanded the modal concept to other field like Temporal modalities (always, sometimes, never), but he could not get out the Aristotelian context. The concept expended in contemporary logic system to include other sort of modality like: epistemological, deontic, tense ... This resulted the emergence of contemporary logical systems, (epistemic logic, deontic logic, tense logic), whose approach differs from the traditional one. The propose of the article is to show the difference between the approaches
Keywords: Logic; Modality; Epistemological; Deontic, Temporal; Truth; False.