PLATO

(427-347 BC) Greek philosopher; emphasized two planes: ideal (noumena) and real ( phenomena ); pre-existence theory of souls; innate knowledge; learning is recalling; greatly influenced Western philosophy. With Democritus , Plato starts from Protagoras 's perception theory of knowledge. Reason and insight discover in perceptual phenomena the universals, i.e., the Ideas, or intelligible forms of reality (rationalism and intuitionism ). Knowledge develops through three stages, corresponding to the relative development of the three levels of the soul: doxa (opinion or mere belief deriving directly from senses); dianoia (rational or discursive understanding); noesis (direct intuition of the Ideas). Knowledge has as its object what really is, i.e., being, essence ( ousia ), the Ideas or the Forms; and virtue. "Virtue is to be gained only through right knowledge and knowledge is cognition of true Being." See Plato's discussion of the divided line in Book VI of the Republic. The moral universals or ideals of Socrates acquire ontological status (i.e., become the basis of reality). The Ideas are eternal and perfect; real; suggested, approximated, or imitated by the things of the world of phenomena ; grasped by reason and intuition; objective (independent of minds or knowers); ordered in a hierarchy under the higher and more universal ideas of being, virtue, beauty, and truth, which in turn participate in the absolutely universal Idea of the Good; ordered toward the idea of the good as the ultimate limitation, purpose (teleology); the intelligible ideals that structure the endless flux or becoming of phenomena ; revealed to the soul (mind) by a process of recollection or memory of a past existence. The two fundamental kinds of reality are the Ideas, which are independently real; and phenomena , which are dependently real. To these could be added the agent or creator (God) who forms the world according to the Ideas. Phenomena comprise the space-time world that approximates the eternal and real world of the Ideas. The soul (mind) is preexistent and immortal. The soul (mind) links the body as phenomena (becoming) to the Ideas (being). The soul (mind) brings life and knowledge to the body. the soul (mind) establishes this link through three functions: appetite (impulses or sensuous desires originating in the belly); will (ambitions or spiritual energies originating in the breast); reason (insight or understanding originating in the mind) and corresponding to, as well as yearning for, the immortal world of the Ideas (which is its source). The soul (mind) is likened to a chariot. Two horses (appetite and will) move it, under the guidance of reason. The three functions of the soul are correlated to the three kinds of knowledge (mentioned above); three classes of the ideal state; nature and goals of education. The harmony of society is compared to the harmony of the functioning of the soul. Realization of the ideal harmony of functioning is justice. The supreme good ( summum bonum ) is justice. Justice is obtained with temperance of appetite and courage of will guided by wisdom of the soul. Wisdom is desire and search for ( eros ) and finally knowledge ( episteme ) of the Good.