Resumen:
The dialectician knows that Ideas are not ultimate entities, after which it is impossible to ask again. For this reason, precisely, the dialectician differs from the mathematician. The famous "Doctrine of Ideas", as it has been closely linked to Plato throughout the history of thought until today, responds to a representation that belongs to the perspective of the mathematician. As a mathematical formulation, with its useless duplication of reality, it has already been rightly criticized by Aristotle. However, what was subjected to criticism in this way was a doctrine of ideas without dialectics. To this extent, it remains detached from the idea of the Good. The Platonic treatment of the idea of the Good shows that the knowledge related to this idea can never be given entirely in the form of a knowledge related to objects. The idea of the good is not an object to be known, but the correlate of the practical competence of using all forms of knowledge, giving them purpose and making them useful for the agent. This point constitutes one of the lasting fruits of Platonic thought on the idea of the Good. Plato diagnosed the provisional character of all objective knowledge and warned that neither the best theory nor the best system of rules is of any use, if there is a lack of practical competence - whose acquisition requires a sustained and systematic exercise - to deal with theories and rules in a useful way, that is, in a way that serves the actual end of the agent/knower.
