Zalta on Unnecessary Logical Truths

According to a traditional view all logical truths are necessary; however، this thesis recently has been faced with various critiques from different points of view. Introducing some logical operators، David Kaplan and Edward Zalta claim that there are logical truths regarding common definition ‒ that are not necessary. William Hanson objects Zalta''s examples believing that they rely on unjustified presuppositions; especially he does not accept real world validity as a proper notion for presenting logical truth. Nelson and Zalta reply to his objections claiming that they have unacceptable grounds. In this paper، we introduce logical truths، then present Kaplan''s and Zalta''s examples and explore Hanson''s objections together with their replies. At last we try to show the metaphysical roots of the debates.