In The Republic, Plato introduces a philosophy that transcends the exclusivity of contemplative and active lives. He defines ultimate truth as “aletheia,” which literally means “unhidden” or “that which does not go unnoticed.” Through his use of the term and his allegory of the cave, Plato strongly implies that philosophers must actively seek to discover absolute truth, rather than relying on traditional methods of contemplation and the persuasive tone of rhetoric to prove its existence. To better explain his reasoning, Plato constructs a metaphor between the sun and the ultimate good. He argues that “the soul is like the eye” in that it requires an external force to establish clarity of vision (Book VI p. 25). When the ultimate good illuminates an idea with truth and reason as the sun illuminates an object, the soul understands with clarity. When an idea is not enlightened, the soul perceives nothing clearly and retreats into the ignorance of an unenlightened opinion. Plato extends this metaphor throughout his writings and successfully connects the complexity of the intellectual world to the tangibility and familiarity of the visible world. In this way, Plato allows for a complete understanding and, by only suggesting his position with figurative language and dialectic, he encourages Glaucon and the reader to arrive at their own realizations of the ultimate good, thereby realizing "aletheia." Plato introduces the importance of sight and light by comparing the commonalities of the physical realm with the ideals of his higher philosophical realm. Through a series of linear questions, he arrives at the conclusion that the sun is "for the visible world in relation to sight" as "good middle of paper...... light and reason be understood.Point Importantly in Plato's definition of true knowledge, Plato distinguishes between truth and ultimate good. In the allegory of the cave, “truth [is] literally nothing but the shadows of images,” a subjective quality that depends on opinion and perspective (Book VII, p. 2). The ultimate good, however, exists universally, independently of “the use of images as in the first case, but proceeding only in and through the ideas themselves” (Book VI, p. 27). By blending the clear, discrete definitions of these terms with the uncertainty of dialectic, Plato succeeds in introducing his revolutionary ideas with clarity while allowing the reader to consider the truth of these ideas rather than encouraging their blind acceptance. The Republic. in the Course Reader. All quotes refer to this work.