this essay analyzes the necessary knowledge process to reach a correct definition of an object, developed by plato in the statesman. starting with the problems found in the search of a definition in the meno, the paper shows that, in his late philosophy, plato reshaped the characteristics of the search that leads to answer properly "what is x". in the statesman, the act of definition becomes a complex process that includes a negative approach to the object. "to say what the object is not" constitutes one of the necessary moments to reach a real definition. this view also implies to move away from the ignorance as a starting point of all kinds of search usually represented in the dialogues by the socratic intransigence.