The Theory of Forms
In the early dialogues, Socrates searches for answers to his questions. In the Euthyphro, for example, after Euthyphro suggests that he is expert in matters having to do with piety, Socrates asks Euthyphro what piety is. Commentators traditionally describe Socrates as asking for a "definition," but he is not interested in the meanings of words. He wants to know what piety is.
This understanding of the search for definitions seems to presuppose that piety is something and thus that it exists. Plato's Theory of Forms is a theory about the existence of piety and the other things Socrates asks about. The Theory of Forms is thus a thesis in ontology:
• the things (piety, justice, and so on) that Socrates asks about exist
• each of the things Socrates asks about is identical to a "form" (εἶδος)
• the form is specified in a "definition" of the things Socrates asks about
It is also part of the Theory of Forms that ordinary F things (ordinary things that are pious, just, beautiful, and so on), are F (just, beautiful, and so on) because they "partake" or "participate" in the form the F itself (piety itself, justice itself, beauty itself, and so on)
• F things are F because they participate in the form the F itself
Plato seems to have realized that this "participating" or "partaking" relation is puzzling. In the Parmenides, which is traditionally thought to be a late dialogue, he has the older and wiser Parmenides asks the young Socrates questions. Socrates has trouble defending his answers to these questions. He suggests and retracts various answers, in the manner of his interlocutors in the early dialogues. Finally, he attempts one last answer to defend his belief in forms. He says that "what appears most likely is that the forms are like patterns, or paradigms, set in nature, and other things resemble them and are likenesses; and this partaking of forms is, for the other things, simply being modeled on them" (Parmenides 132c-d).
The Good itself
What Socrates says about "the good itself" (τὸ ἀγαθὸν αὐτό) is extremely difficult to understand in complete detail.
His view seems to be that the good is the first principle and, as such, is responsible for knowledge and existence of the forms but is itself beyond these forms (Republic VI.508e-509c). The cognition to grasp the good is "mind" (νοῦς). This kind of cognition develops out of three lower kinds (in order form highest to lowest): "intelligence" (διάνοια), "confidence" (πίστις), and "image representation" (εἰκασία). To grasp the the good is the primary point of education (Republic VII.518b-d). The process takes fifty years (Republic VII.540a).
"Whenever one tries though dialectic (διαλέγεσθαι), without the senses but by reason (λόγου) alone, to find each true reality and does not give up before apprehending the good itself (ἀγαθὸν αὐτῇ), one reaches the final goal of the intelligible" (Republic VII.532a). "They would keep looking back and forth to justice, beauty, moderation, and all such things as by nature exist, and they would compose human life with reference to these" (Republic VI.501b). "We shall require them to turn upwards the vision of their souls (ψυχῆς) and fix their gaze on that which sheds light on all, and when they have thus beheld the good itself they shall use it as a pattern (παραδείγματι) for the right ordering of the state and the citizens and themselves throughout the remainder of their lives, each in his turn, devoting the greater part of their time to the study of philosophy (φιλοσοφίᾳ), but when the turn comes for each, toiling in the service of the state and holding office for the city's sake, regarding the task not as a fine thing (καλόν) but a necessity; and so, when each generation has educated others like themselves to take their place as guardians of the state, they shall depart to the Islands of the Blest and there dwell. And the state shall establish public memorials and sacrifices for them as to divinities if the Pythian oracle [Apollo's priestess at Delphi] approves or, if not, as divine and godlike men" (Republic VII.540a-c).
The Just Life is Better
If the soul is just, its parts are organized so that action is in accordance with the knowledge of the good. This knowledge belongs to reason. In this part of the soul, there is the knowledge that existence in the body is temporary, that the body and its needs are distractions, and that the good most of all resides in a certain exercise of theoretical reason involving knowledge of the forms.
1. Is it possible for some unjust life to be better than some just life?
Glaucon sets a very high bar. He asks Socrates to show that a just human being who suffers what are popularly understood as great misfortunes is still better off, even if the comparison is to an unjust human being who suffers none of these so-called misfortunes but instead is showered in what are popularly understood as the good things in life.
"We must take away his reputation, for a reputation for justice would bring him honor and rewards, so that it wouldn't be clear whether he is just for sake of justice itself or for the sake of those honors and rewards. We must strip him of everything except justice and make his situation the opposite of the unjust person's. Though he does no injustice, he must have the greatest reputation for it, so that his justice may be tested. ... [T]hose who praise injustice at the expense of justice will say that a just person in such circumstances is worse because he will be whipped, stretched on a rack, chained, blinded with fire, and, at the end, when he has suffered every kind of ill, he'll be impaled..." (Republic II.361b-362a).
It is not at all clear that Socrates actually meets this challenge. The reason is that he does not explain in any detail what happiness is. The love of wisdom makes a substantial contribution. This much seems clear, but Socrates does not explain how this contribution is weighed in comparison with other things traditionally thought to contribute to or detract from happiness.
Socrates says that there are three kinds of pleasure, one for each part of the soul (Republic IX.580d). The person in whose soul a given part is dominant praises the pleasure of that part the most, but Socrates says that the person with the most experience of these pleasures is the best judge of which of these pleasures is the best (Republic IX.582e).
"Of the three kinds of pleasure (ἡδονῶν) the pleasure of that part of the soul by means of which we learn is the sweetest, and so is the life of the man in whom this part rules" (Republic IX.583a).
In addition, Socrates argues that a part of the soul will get the truest pleasure when it gets what is proper to it. When the appetitive or spirited parts of the soul dominate, the knowledge in the part with reason does not directed action. In this case, the appetitive or spirited parts of the soul direct action to objects that do not provide the truest pleasures.
"Let us confidently assert that those desires of even the profit-loving and honor-loving parts of the soul, which follow knowledge and reason (ἐπιστήμῃ καὶ λόγῳ) and pursue with their help those pleasures which intelligence (φρόνιμον) prescribes, will attain the truest pleasures possible for them, since they are following the truth. These pleasures are their own, if that which is best for each thing may be said to be fully its own. So if the whole soul (ψυχῆς) follows the wisdom-loving part (φιλοσόφῳ) and there is no internal dissension, then each part will be able to fulfill its own task and be just in other respects, and also each will reap its own pleasures, the best and the truest as far as possible" (Republic IX.586d-587a).
2. Why shouldn't the rulers shirk their duty to spend more time in the love of wisdom?
The answer to this question is not completely clear, but it may be that it is rational for the rulers to think that taking their turns in ruling over the city will maximize the time they spend in the love of wisdom and hence maximize the satisfaction they take in life on earth in the body. It is not rational for them to shirk their duty to rule. If they did not take their turns in ruling the city, they would increase the probability of spending less time in the love of wisdom and hence increase the probability of being less happy.
"And so the man proposes the penalty of death. Well, then, what shall I propose as an alternative? Clearly that which I deserve, shall I not? And what do I deserve to suffer or to pay, because in my life I did not keep quiet, but neglecting what most men care for—money-making and property, and military offices, and public speaking, and the various offices and plots and parties that come up in the state—and thinking that I was really too honorable to engage in those activities and live, refrained from those things by which I should have been of no use to you or to myself, and devoted myself to conferring upon each citizen individually what I regard as the greatest benefit? For I tried to persuade each of you to care for himself and his own perfection in goodness and wisdom rather than for any of his belongings, and for the state itself rather than for its interests, and o follow the same method in his care for other things. What, then, does such a man as I deserve? Some good thing, men of Athens, if I must propose something truly in accordance with my deserts; and the good thing should be such as is fitting for me. Now what is fitting for a poor man who is your benefactor, and who needs leisure to exhort you? There is nothing, men of Athens, so fitting as that such a man be given his meals in the prytaneum. That is much more appropriate for me than for any of you who has won a race at the Olympic games with a pair of horses or a four-in-hand. For he makes you seem to be happy, whereas I make you happy in reality; and he is not at all in need of sustenance, but I am needy. So if I must propose a penalty in accordance with my deserts, I propose maintenance in the prytaneum" (Apology 36b-37a).