By „dispute” we mean an argumentative dialog where each of the two parts state opposite theses. Two sentences can be contrary if they have similar reference, but incompatible predicates (SIP – sentences with incompatible predicates). Usually, the disputes are solved using force in different ways, but that does not mean that the winner is right and his thesis is true. Therefore, we cannot evaluate a thesis on the ground of its success, but we need a reference mark for that. According to the Sophist school, the individual is the only reference mark, so any SIP is equally justified. The absolutist point of view claims that there is an objective reference mark and, consequently, the truth is, at its turn, objective and unique. Finally, the relativist orientation rejects any objective reference mark, but the right thesis is not arbitrary, as the sophists thought, it is true relatively to the state of the evaluator to a given moment. It follows that, for any evaluator, at a moment of time, only one SIP is true.