Plato’s Republic develops the concept of the types of knowledge. The primary division of Plato’s classification is the division of knowledge into sensory and intellectual knowledge. The first category of knowledge, namely sensory knowledge, is perceived as a lower type, and intellectual knowledge is the higher one. Intellectual knowledge is divided into “thinking” (noesis) and “reason” (dianoia). By “thinking,” Plato understands the activity of the mind alone, free from the admixture of sensuality. By “reason,” Plato understands this kind of intellectual knowledge, in which the subject of cognition also uses the mind to understand sensible things. Sensual knowledge Plato also divides into two areas: “faith” (pistis) and “likeness” (eicasia). Through “faith,” one perceives things as existing and affirms them as such. “Likeliness” is no longer a kind of perception but an intellectual action with sensory images of things. According to Plato, feelings cannot be the source of true knowledge; he considers knowledge as “ability” or even “power,” the most influential of all that a person possesses.
Closely related to these differences is Plato’s distinction between knowledge and opinion. The opinion is neither knowledge nor ignorance; it is vaguer than knowledge but more precise than ignorance; it is in between these two categories. Unlike opinion, knowledge is a potency, a special kind of existence. I understand Plato’s distinction between opinion and knowledge; opinions can be both true and wrong, and their true value can fluctuate.
Socrates, the protagonist in Plato’s Republic, suggests creating an ideal city as a model for regulating the individual soul. The city’s guardians must be moral and unselfish, living modestly and communally as soldiers do in their camps. Thus, according to Plato, people who have a moral and intellectual approach to governance issues should govern a just republic. These people in their decisions should rely on the knowledge because only it can provide them with an accurate perception of reality, free from feelings. The opinions of modern politicians, such as, for example, Joe Biden, influence the decisions made in government, which, from Plato’s point of view, is not acceptable. The mental activity of the head of state should be aimed at comprehending eternal questions, not the current and changing world.