Plato's Ethics as a Reply to Glaucon's Challenge

Sandra LaFave

The Republic, Book 1, poses the egoist’s question: Why be consistently moral? Why not be moral only when it pays to be moral? Why not be immoral if you can get away with it? Read about Glaucon's challenge in the Ethics portion of your Plato readings in Palmer.

Note that Plato is not an ethical egoist. Plato has Glaucon give egoist arguments in order to reply to them in the rest of the Republic.

Plato’s epistemology

Plato studied geometry with the Pythagoreans. He was amazed that geometrical statements — such as “The area of the circle is πr2” — were true of all circles (universally) and were always true (unchanging). Math demonstrates that universal and unchanging knowledge exists. For Plato, universal and unchanging knowledge is clearly better (“higher”) than particular and changing (sensory) knowledge. In fact, for Plato, so-called “knowledge” from the senses, which is particular and changing, shouldn’t really be called knowledge at all.

The move to metaphysics

For Plato, as for us, all knowledge is intentional, i.e., knowledge of something. If the geometers know something, then, there must be something they know. The unchanging universal realities known through math — such as “the circle” — must exist. That is, math knowledge reveals a world of universal and unchanging realities. Plato calls these realities the Forms.

Forms are archetypes or models. Things in the world of the senses “imitate” or “participate in” Forms. An X is an X precisely because it imitates or participates in the Form of X  (Xness).   Plato reasons that there must be Forms for every thing that has being: trees, rocks, stars, circles, etc. Plato is especially interested in Forms of moral and aesthetic characteristics such as Beauty (the thing all beautiful things have), Courage (the thing all courageous people have), and Goodness (the highest Form).

Things in the world of the senses change; they go in and out of being. The Forms, according to Plato, do not change. For example, the Form of Treeness does not lose its leaves, or die. Thus, for Plato, the Forms have more reality or being than things in the world of the senses. Not only is an X an X because it imitates or participates in the Form of X  (Xness); an X becomes more of an X (it has more being or reality) the more completely it imitates or participates in the Form of X.

Conversely, a thing has less reality the farther removed it is from its Form.

The move to ethics

Furthermore, since Xness (the Form of X) constitutes perfection of Xness, a particular X becomes a better X the more completely it imitates or participates in the Form of X. And the more completely an X imitates or participates in the Form of Xness, the more of an X it is, i.e., the more being it has. A better X is one that has more Xness or is closer to Xness itself; a worse X has less Xness. More reality = more goodness, and less reality = less goodness.

Now, since a thing has less reality the farther removed it is from its Form, it follows for Plato that evil or badness is a lack or absence or “privation” of being. Bad things lack goodness, which is the same thing as saying bad things lack reality. Badness-in-itself doesn’t exist for Plato. Thus there is no Form of Evil or Badness which bad things possess.

Philosophy of mind

For Plato the soul has three parts: (1) reason; (2)"spirit" (the Greek word for the second part of the soul is "thumos", meaning aggressive energy); and (3) appetite. Reason is the faculty of the soul that can do math-type, abstract thinking, and thus apprehend the Forms. Plato thinks that if people systematically train their faculty of reason to handle greater and greater abstraction, some will finally attain knowledge of the highest Form, the Form of the Good.

Since being a better X is approaching more closely the essence or Form of X, being a better person is approaching more closely the Form of Personhood — being more completely human. The distinctively human capacity is the capacity to reason abstractly; that’s what makes people different from other things. Thus, the better a person can reason (simultaneously coming closer to apprehension of the ultimate Form, the Form of the Good), the better (and more human) a person is. The most realized, highly-developed, rational, and real person is the one who knows Goodness itself. Knowledge of Goodness itself is transformative, paradigm-shattering. One who has such knowledge will effortlessly recognize and promote Good in the world.

Political philosophy

Such Reasoners, then, are best suited to rule the state. Citizens can be grouped according to which part of the soul predominates in them: thus, some people are suited to be reasoners, some to be soldiers or police (the thumos people), and some to be craftspersons (the appetitive people).


Plato thinks a well-ordered soul is structurally just like a well-ordered state.

A well-ordered, good, soul is one in which Reason rules. Such a soul, at its best, exercises virtue effortlessly as a result of the transformative experience of Goodness itself. Such a soul is psychically integrated, happiest, sanest, most moral, most free, and most fully human. Plato’s answer to Glaucon, then, is that one should strive to be a moral person because being moral, being reasonable, being happy, being sane, being free, and being fully human are all the same thing.

One whose soul is not well-ordered, not ruled by reason, is psychically dis-integrated, unhappy, immoral, a slave to passion, less than human.  The psychically dis- integrated soul is sick; it is afflicted with akrasia (the origin of the English word "crazy").

A well-ordered, good, state (the ideal Republic) is one ruled by reasonable people, who, because they know Goodness itself, are guaranteed to rule wisely. In a well-run state, people are happy because they do the kind of work they are suited for. Not all people are suited to the life of reason, according to Plato, so the Republic will not be a democracy. People who do not or cannot reason well should not rule.

A badly-ordered state is in chaos. Allowing aggressive soldiers (e.g., Klingons) or appetitive craftspeople (e.g., Ferengi) to rule the state is like letting the inmates run the asylum. Such a government makes it difficult for its citizens to live fully human lives. People must perform jobs they’re not suited for, so everyone is personally unhappy. Unwise, shortsighted rulers are not wise, so there is rebellion and conflict within the state. Reasonable people will be persecuted, even executed (as Socrates was).

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