Category: Philosophical theories

The Form of the Good

Plato discusses the Form of the Good only in the Republic. There, it is introduced as the hierarchically supreme Idea, and the reason for the existence of all other Forms. In the last phase of Platonic philosophy, in Plato’s so-called unwritten doctrines, that same role is held by the One

According to Plato’s theory of Forms, outside the ever-changing sensible reality there exist certain self-contained, immutable and intelligible entities, the Forms. The objects of the sensible world owe their existence and any truth they possess to their being related to the Forms – in Platonic terminology, sensible things “participate” to the Forms and “imitate” these Forms.

The foremost Platonic Forms are moral values: piety, bravery, sagacity, justice. It is in fact possible that Plato conceived of his immutable Forms as a response to the moral relativism of the Sophists, which encapsulated the predominant moral stance of the Athenians at the end of the 5th century BC. Yet, are all moral values equally important? Are all Forms equivalent? Already in the early dialogue Euthyphro it is indicated that the subsumption of piety to justice is acceptable: what is pious forms part of what is just – it is that part of justice that pertains to our stance vis-à-vis the gods. Therefore, apparently the Form of Justice is hierarchically superior to the Form of Piety.

In the Republic, after describing the three social classes in his ideal state and the tripartite division of the human soul, Plato attributes to each of these a fundamental virtue -sagacity, bravery, and wisdom-, while Justice will be considered as a form of balance between these virtues. Before moving to the education of the Guardians of the ideal state, Plato’s Socrates declares that his approach has been “deficient” because he was overlooked the rapport of the fundamental virtues with the Good (504b). The “τοῦ ἀγαθοῦ ἰδέα” (=Idea of the Good) is defined as the “μέγιστον μάθημα” (=greatest lesson), the highest possible knowledge, “through which just things and the like become useful and beneficial” (505a). If future rulers are not instructed on the relation of the virtues with the Good, their education will remain incomplete.

Socrates resists his interlocutors’ pleas to define the Good, suggesting instead an indirect approach through the three famous parables: The Allegory of the Sun, the allegory of the Divided Line, and the allegory of the Cave. In that way, even if the Good does not receive a precise definition, it will be nonetheless revealed, in Socrates’ words as the “an offspring [ἔκγονος] of the good and most like it” (506e). The Sun, whose light is the reason sensible beings become visible, but also receive life, is an “offspring” of the good; in the universe of sensibles it holds a role similar to the Good in the universe of intelligible things. Thanks to the Idea of the Good, the soul conceives of intelligible beings and attributes to them their truth, but, furthermore, the Idea of the Good is the reason for the existence of the other Forms.

“Well, understand the soul in the same way: When it focuses on something illuminated by the truth and what is, it understands, knows, and apparently possesses understanding... So that what gives truth to the things known and the power to know to the knower is the Form of the Good. And though it is the cause of knowledge and truth, it is also an object of knowledge. Both knowledge and truth are beautiful things, but the Idea of the Good is other and more beautiful than they.” Republic 508d-e
“Therefore, you should say that not only do the objects of knowledge owe their being known to the Good, but their being is also due to it, although the Good is not being, but superior to in rank and power [οὐκ οὐσίας ὄντος τοῦ ἀγαθοῦ, ἀλλ' ἔτι ἐπέκεινα τῆς οὐσίας πρεσβεία τε καὶ δυνάμει ὑπερέχοντος].” Republic 509b

In the parable of the Divided Line, the Form of the Good is described as the “ἀρχὴ τοῦ παντός”, a first principle that exists independently of our views, a first principle that is “ἀνυπόθετος” (=unhypothetical, 511b-c), and will form the final step in the process of acquiring knowledge and in the hierarchy of what is. In the suggestive parable of the Cave, the Good is that which is finally revealed to the freed prisoners, blinding them with its radiance. The Form of the Good is therefore something more than then hierarchically supreme Form. Plato seems to attribute to it the role of a first principle; it is placed above the Forms and is somehow responsible for their existence.

In his later dialogues, Plato refines the method of “division” and “induction”, i.e. the systematic mapping of the Forms and the study of their interrelations. Although these dialogues contain no reference to the Form of the Good, one can suppose that the Good was still to be conceived of as the most general Form.

Expressions such as “ἀνυπόθετος ἀρχὴ τοῦ παντός” and “ἐπέκεινα τῆς οὐσίας” (=beyond Being), have led to the view that the Good of the Republic should be identified with the One of Plato’s so-called “unwritten doctrines”, that is his oral teachings, reserved solely for initiated members of the Academy. Other scholars have identified the Good with the Platonic god. In any case, Plato's positing of the Good as “ἐπέκεινα τῆς οὐσίας” still signifies something rather simpler: that, for Plato, all of knowledge has moral foundations; that morality comes before epistemology. Plato embraces the Socratic imperative that virtue is knowledge; yet, he also accepts its reversal: knowledge is virtue. That is why he places the foremost moral Idea at the hierarchical apex of his Forms, the Form of the Good, i.e. virtue itself. In Greek, the terms “τὸ ἀγαθόν” and “ἀρετή” are equivalent.

Author: Vassilis Kalfas
  • Annas, J. An Introduction to Plato’s Republic. Oξφόρδη, 1981.
  • Kraut, R. ed. The Cambridge Companion to Plato. Cambridge, 1992.
  • Kraut, R. "Plato." Zalta, E.N ed. Stanford Encyclopeidia of Philosophy 2013.
  • Pappas, N. Routledge Philosophy Guidebook to Plato and the Republic. London, 1995.
  • Ross, W. D. Plato’s Theory of Ideas. Oxford, 1953.
  • White, N. P. Plato on Knowledge and Reality. Indianapolis, 1976.


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