The dissertation aims to present a defense of the principle of noncontradiction, a defense supported by two arguments. In the first argument, it is emphasized the relation between the validity of the principle of non-contradiction and the determination of the sense of linguistic expressions, in particular, the determination of the sense of general terms used as predicates in singular sentences. To say of an object that it has and, in the same respect, does not have a certain characteristic would result in the indetermination of sense, namely that nothing would be understood by the sentence. The second argument seeks to establish a relation between the use of instances of the principle of non-contradiction and the ability to identify particular objects. To refer specifically to a single individual, in such a way that it can be thought of as a subject of predication, it is necessary to identify this individual by means of a sortal term and not simultaneously through an opposite sortal. More precisely: trying to refer to a thing as being and not being of a certain sort would result in the indetermination of the reference, viz. no single object would be identified.