Introduction
Plato's Republic is both a political and a moral work in that it discusses both individual morality and the nature of justice in a political community. The book's argument is focused on a discussion of the benefits of justice to the individual, and it ends when Socrates is done describing the benefits both in this life and the next of practicing justice. However, in the course of this discussion many political issues are discussed. Whether or not Plato wrote Republic primarily as a political or moral work, the city/soul analogy means that it necessarily carries a political message. This message is twofold.
Firstly, it contains a specific and prescriptive political program which describes how to establish a city which is 'wholly good' (427e). Secondly, it contains a more general message, one which is highly sceptical about politics as an activity and very pessimistic about the possibilities of collective human action. The philosopher-kings gain most pleasure from engaging in contemplation with their peers, but must engage in political action by necessity to keep the city going and so maintain the conditions for their own personal fulfilment. Hence it is man's fallibility which makes politics necessary, so the philosophers have no choice but to descend back into the cave to engage in it. Callipolis is designed so as to contain the optimum amount of justice – as a political community it is just, and the individuals within contain balanced and just souls. One would not be possible without the other, and so both are interconnected.
The political
The political dimension of The Republic first becomes apparent when Thrasymachus claims that no city exists which is non-exploitative, something Socrates never refutes. He instead describes how the ideal form of such a city can be logically imagined, whilst admitting that it would require 'heaven-sent' conditions for it to come about (592a – b). In constructing the concept of the ideal city, Plato, through Socrates, passes extensive comment on how the politics of the city should be constructed. Its institutions are described, as are its fundamental laws. The system of education is specifically designed to perpetuate the political system that the interlocutors lay down, and itself is deemed sufficient to guarantee that legislation in the areas not specifically discussed will be worthy of the city.
In the light of the latter, Plato could be seen to be cutting the political discussion short to get back to the topic of personal morality. However, the discussion of the city's laws, culture and institutions seems to exceed that which is necessary to sustain the analogy to the soul. Plato's focus here on education carries a joint political and moral message. Plato is convinced of man's educability, and education is a way of forging a cohesive political community and guaranteeing it does not disintegrate.
However, it is also the key to an individual striking the balance in their soul between the three warring parts and hence attaining individual morality. Here we see one example where the political and moral parts of The Republic are inseparable – the city could not be ideal without the education proposals laid out, and these proposals are designed to hone the individual morality of individuals. A political order, as an aggregate of individuals, necessarily takes its character from the nature of these individuals. Hence these proposals are politically and morally desirable.
Early on, Socrates decides on a definition of justice which is essentially political. Justice, he says, consists of 'this business of everyone performing his own task' (433b). The principle of the division of labor was established early on as necessary to producing an effective city, but this division necessarily intertwines people together and requires them to make moral choices in their lives. It is important that early on Plato puts the following words in Socrates' mouth: 'The origin of a city lies, I think, in the fact that we are not, any of us, self-sufficient; we have all sorts of needs' (369b). As none of us are self-sufficient and we hence have to live in political communities, questions of morality are all asked within this framework.
This means that The Republic's moral component must have a political dimension, even if it is possible to imagine Socrates' definition of the good life as possible outside of a political community. Philosophers could theoretically spend their time seeking the Form of the Good outside of a human society, but the interlocutors decide when they reject the 'city of pigs' (the uncultured city) that by eliminating culture from their city they would also eliminate education, and so create a city of idiots: hardly likely to produce philosopher-kings. Civilization is hence a prerequisite for philosophizing and achieving morality. As Plato also writes throughout The Republic of the danger of adverse social and cultural contexts tarnishing the morality of an individual, the nature of the political context becomes a matter of first order importance in Plato’s discussion of justice in the soul.
The second source of political discussion to Plato in The Republic is the city/soul analogy. After the long discussion of the city’s laws, institutions and its culture, he turns to the soul and carries the parts of the analogy across which he believes to be relevant. The most relevant part in his opinion is the division of labour – as the city is divided into several classes of people who form distinct functions, the soul has a similar tripartite division. However, it must be questioned whether the analogy is logically viable. Socrates believes that the city’s excellence consists in its division of labour and specialization, but it does not necessarily follow that this must be the source of the soul’s excellence. This means the analogy does not necessarily strengthen Plato's argument, and the discussion of the soul’s nature would have been possible without using analogy at all.
However, the analogy is an incredibly rich heuristic device and allows Plato to make relevant comments on both morality and politics simultaneously. In this way as well it is impossible to separate the political parts of the work from the moral; as Thrasymachus remarks, the character of a city's political order reflect the character of its rulers, be they the whole people in a democracy or one tyrant. However, it is telling to consider just how utopian the city used in the analogy is, although the analogy still holds because Socrates also considers it a remote possibility that a philosopher-king with an analogously well-ordered mind could emerge.
Like the Form of the Good, the ideal city cannot be known outside the world of forms, but virtue is sufficiently constituted by a constant orientation towards the good, or towards the ideal city. The Republic hence describes a political techne (science) possessed by philosopher-kings by which the perfect city can be aimed for, even if the light from the Good can never penetrate the cave and illuminate it entirely.
The moral
The moral element of The Republic argues that personal morality and justice consist of having a well-balanced and cohesive soul in which reason is sovereign, spirit the deputy, and the desires are restrained. This is a rather strange concept of personal morality, as it does not make any specific prescriptions on the activities of 'making money, or taking care of his body, or some political action, or contractual agreements with private individuals' (443e) which Socrates says a man with such a soul can now engage in. At this point in the dialogue, Socrates has done little to convince us that a man with such a soul will act in a way which is considered just.
It is when he comes to describe the character of the tyrannical individual that Socrates describes why a well-ordered soul will cause an individual to act justly. An unbalanced soul is associated with rampant desire and hence immorality and criminality. The morality of the philosopher-king resides in his constant orientation towards the Good and his all-consuming eros (desire) for it, qualities which are likely to dissuade him from dissolute or immoral behaviour. The morality of the rest of the population is taken to be represented by their deference to the class hierarchy and the sovereignty of the philosopher-kings in matters of rule, as they do not have knowledge of the political techne.
There are hence different rules for different groups in the political order, which confuses The Republic's moral message and the issue of whether it is primarily political. As has already been noted, orientation towards the Form of the Good is a theoretical possibility in a non-political environment; however, the moral behaviour of the mass of the population is defined with reference to the city. The philosopher-kings are not much freer, for if they choose not to rule then the city will disintegrate and they will become corrupted and unable to seek the Good.
Conclusion
It appears then that the relationship of politics and morals in The Republic is highly complex. The inner polity of the soul and the outer polity of the city cannot exist without each other, and so it is conceded that neither form will ever exist in reality. Plato says that the only politics a philosopher-king would wish to engage in are those of the perfect city, and as the perfect city can never exist he is sending a highly pessimistic message about politics in general: individuals who are supremely virtuous and wise shun politics down in the cave.
The city itself is only held together by an elaborate system of lies and myths which deny most of the common people their individualism, and the philosopher-kings are taken to be acting morally because of their individual search for wisdom, not because of their civic values or method of rule. The Republic's account of political justice is hence very basic, as it is taken to consist in the utilitarian notion that everyone should do what they are best at, acting in a merely supporting role for the ultimate good. There is little clue as to how people should conduct themselves in everyday affairs, although we are told that when properly educated they cannot fail to do so. Furthermore, the relationship between the rulers and the common people is far from ideal –
'Don’t you think it's a disgrace, and a sure sign of poor education, to be forced to rely on extraneous justice – that of masters or judges – for want of a sense of justice of one's own?' (405b)
The good and virtuous life is unattainable for those who must have surrogate justice through the decisions of others. The appropriate conclusion seems to be that The Republic is primarily a work expressing a morality of the excellent life, a life which is beyond the reach of most people. As a political order must by necessity exist, it should be one which advances the virtues of the excellent life and facilitates those capable to seek the Form of the Good. However, this order requires the existence of individuals with the morality which Plato considers to be supremely virtuous and it exists to perpetuate this virtue. The perfectly balanced inner polity of the guardians is hence the key to the city's political structure, and is in fact a corollary of the political techne they possess by virtue of their balanced souls. So, in the final analysis, The Republic is primarily a moral work, but one which passes extensive comment on the nature and practice of politics, which is itself inseparable from the psychology of the individuals who practice it.