عنوان مقاله [English]
Almost all logicians agree on the definition of statement as a declarative sentence which can bear truth and falsity. Every statement is essentially either true or false, which is the reason why determining the truth value of a statement is coherent with the principle of excluded middle. According to this principle, a statement can be either true or false and no third alternative is possible. This holds for all kinds of declarative statements with absolutely no exceptions.
Nevertheless, since the dawn of philosophic thought, there have been people, particularly among Greek philosophers, who came up with statements that could cast a shadow of doubt over the aforementioned principle. These alleged counter-examples are what we know today as logical and semantical paradoxes which although of a great variety, they have some more famous instances which are more complicated and perhaps more practical. To mention the most well-known of the paradoxes we can refer to the Liar paradox whose resolution can lead to the resolution of all the others since they are all of one and the same nature.
The present article focuses on the nature and origin of paradoxes as well as various attempts of logicians in resolving it.