I am currently writing a book on the history of moral thought, which will be published next year by Atlantic. I will from time to time post in Pandaemonium small sections from the book  and open it up for discussion. Last month, I published the opening section of Chapter 1. This month’s excerpt is from Chapter 2 which explores the moral thought of Socrates and Plato. Much of the chapter discusses Plato’s masterpiece The Republic, a key work in which the many threads of Plato’s argument about the relationship between politics, philosophy and the conception of the good life come together.

Like most of Plato’s works The Republic is written in the form of a dialogue, with Socrates acting as Plato’s mouthpiece. At the beginning of the work the Sophist Thrasymachus challenges the very idea of morality, insisting that ‘Justice is nothing other than the advantage of the stronger’. There were, Thrasymachus observes, many kinds of cities in Greece – democracies, oligarchies, military dictatorships, tyrannies. Each had a different conception of justice, but all benefited the ruling class:

Democracy makes democratic laws, tyranny makes tyrannical laws, and so with the others. And they declare what they have made – what is to their advantage – to be just for their subjects, and they punish anyone who goes against this as lawless and unjust. This, then, is what I say justice is, the same in all cities, the advantage of the established rule.

What is called justice is, for Thrasymachus, simply injustice writ large.  Those who commit small crimes, he observes, ‘are called temple-robbers, kidnappers, housebreakers, robbers and thieves when they commit these crimes.’ But when someone ‘in addition to appropriating their possessions, kidnaps and enslaves the citizens as well, instead of these shameful names he is called happy and blessed, not only by the citizens themselves, but by all who learn that he has done the whole of injustice.’ Conventional morality, in other words, is a scam, a set of rules invented by the ruling class to promote its own interests and to keep everyone else in check. Reject the scam, is Thrasymachus’ advice, pursue your interests rather than the interests of others, and disregard justice whenever you can get away with it.

Plato responds to Thrasymachus’ challenge at two levels. First, he set out plans for a social Utopia that links a psychological portrayal of a just person to a political description of a just city to show how naked self interest is harmful to both the individual and the collective soul. Second, he gives a metaphysical account of what it is to be good, challenging the claim that justice is relative to particular cities.

This excerpt, from the final section of Chapter 2, places both Plato’s and Thrasymachus’ arguments, and the idea of ‘self-interest’, in historical context.


In The Republic, Plato links a political argument about the best form of society to an ethical argument about what constitutes the good and how to discover it and binds the two together with a psychological claim about how best to achieve happiness. Goodness and happiness, for Plato, are both the offspring of harmony, of the soul and of the city.

The psychological, the political and the metaphysical arguments have all proved deeply influential, from Christian theology’s appropriation of the transcendental Forms to Sigmund Freud’s tripartite distinction between the ego, id and superego. There is, however, something deeply dissatisfying about Plato’s theory. For a start, it is not so much an ethical as a psychological refutation of Thrasymachus. Plato dismisses naked self-interest not as ethically unsound but as mentally unhealthy.  To be unjust is to suffer from an unbalanced mind.

In large part Plato’s failure to make a properly ethical case against the pure pursuit of self-interest rests on his inability to recognize the force of Thrasymachus’ moral argument. While it is tempting to treat Thrasymachus ‘as someone who is quite obviously wrong’, the philosopher Richard Norman observes, we should in fact ‘take very seriously the possibility that he may be right’; not least because ‘The question, “Why should I pursue my own interests?” seems redundant’ while ‘the question “Why should I heed other people’s interests?” does seem to require an answer.’ That is, however, a question that makes much more sense to a modern mind than to an Ancient one.

The idea of self-interest is, perhaps surprisingly, not self-evident. At different times, in different societies, ‘self-interest’ has meant different things. Compare, for instance, Thrasymachus and Achilles.  Achilles was driven by self-interest. He did not wish to lose his war prize Briseis.  He was more interested in preserving his honour than in defending the interests of the Greeks. Or that, at least, is how a modern viewer would read it. For Achilles, though, his withdrawal of his men from battle in outrage at Agamemnon’s action was not a case of selfishness, nor even of self-interest, but a matter of following the code laid down by his community. That code was often not in the interest of the individual (the highest honour, after all, was death in battle, a fate that was to befall Achilles himself). But, in prizing individual honour above wider needs, nor was it often in the interests of the community either. This was one reason such honour codes slowly evolved into other forms of moral injunctions.

Thrasymachus possessed a very different concept of self-interest. Self-interest, to him, was unrelated to the interests of the community; individuals in his view should not take into account any needs other than their own. Philosophers, both ancient and modern, have shown how such an egoistical view makes little sense. Humans are not solitary creatures but exist only within the confines of a community. It is only through a community of others that an individual can assert his own interests.

Nevertheless, in time, Tharasymachus’ claim that justice is a scam, that it is merely an expression of power, and that the most rational behaviour is to disregard justice where possible and pursue one’s self-interest was to prove almost as influential as were Plato’s own arguments. Hobbes’ notion of bellum omnium contra omnes – ‘a war of all against all’;  Nietzsche’s celebration of ‘the will to power’; Marx’s cynicism about bourgeois morality as an expression of class interests: all echo Thrasymachus.  Hobbes, Nietzsche and Marx are three disparate thinkers. What connects them is that they are philosophers of the modern era, attempting to make a sense of the meaning of political power, individual agency and social needs at a time when traditional moral concepts were in disarray. And to be able to draw on the idea of ‘self-interest’ at the heart of Thrasymachus’ argument, they also had to draw upon a notion of the ‘self’ that neither Homer nor Plato possessed.

From the sixteenth century onwards, a host of social and intellectual developments helped define what we now call modernity – the spread of market forces, the growth of class struggle, the discovery of the ‘inner self’, and the creation of the private sphere. These developments enabled a new sensibility in art and literature that we can see, for instance, in Rembrandt’s self-portraits, in Vermeer’s depiction of the private and the intimate and in the self-consciousness of Shakespearian characters such as Hamlet and Falstaff. They found an echo in theology, in the writings of Luther and Calvin and other thinkers of the Protestant Reformation. And they expressed themselves in politics through Machiavelli’s work.

It was not that many of these thinkers would have agreed with Thrasymachus. It is more that the social and intellectual changes that marked the coming of modernity made an argument rooted in individual self-interest that much more plausible. Even those who disagreed with such ethical claims had nevertheless to take them far more seriously.

In Plato’s world, notions of the inner self were barely articulated, an individual’s identity and interest was bound up entirely with the community in which he lived, the very notion of the individual was far more constrained than it is today, and ethics was a means of regulating the social roles and relationships within a community. The importance of the community was expressed in the special place that the polis possessed in ancient Greek life. ‘Polis’ is today usually translated as ‘city state’, but to Plato and Socrates, to Euripides and Sophocles, it conveyed something far deeper and almost spiritual. Not only did the polis embrace a community’s social, cultural and political life, it was also the concrete expression of that community’s place within the Greek tradition. It was through the polis that the individual citizen discovered his identity and through which he became part of a history and heritage. Even today there is a fraught debate about how to balance individual rights and social needs. Two millennia ago the idea of naked egoism as expressed by Thrasymachus may, indeed, have seemed a form of mental illness.

Even given all this, however, there remains something not merely dissatisfying about Plato’s notions of justice and goodness but also deeply distasteful about them. Plato’s Republic is a world in which everybody knows their own place, everybody minds their own business. Justice, as Plato puts it, ‘is doing one’s own work and not meddling with what isn’t one’s own.’ It may be a vision that owed much to the traditional Greek vision of the universe as a place where everything had its place and function. It was also, however, an argument for the rationalization of injustice.

A slave or a manual worker is ‘despised’, Plato argued, because within him, ‘the best part [of the soul] is naturally weak’ and ‘can’t rule the beasts within’.  So, ‘to ensure that someone like that is ruled by something similar to what rules the best person, we say that he ought to be the slave of that best person who has a divine ruler within himself.’ He said this not out of a desire ‘to harm the slave’, as Thrasymachus believes, ‘but because it is better for everyone to be ruled by divine reason, preferably within himself and his own, otherwise imposed from without.’ And since by definition a slave or a manual worker cannot find reason within himself, it is best for the harmony of his soul, and for the city in which he lives, for such reason to be ‘imposed from without’. For Thrasymachus justice is meaningless because strong should rule the weak. For Plato justice requires that the strong should rule the weak (or, at least, that the strong-minded should rule the weak-minded).

Slavery, to a modern ethical consciousness, is unconscionable, because justice requires not simply harmony but also equal treatment. All humans are morally equally, and no one can rule any other without their consent.  Slavery cannot bring about harmony because the very act of enslavement is, in modern eyes, to create disharmony.

It would, of course, be anachronistic to berate Plato for not being a modern liberal. Nevertheless, even from the perspective of Plato’s own time, his ethical arguments are questionable.  Plato’s real target was not the amoralism of Thrasymachus but Athenian democracy. His was an ethical argument in defence of the right of the few to rule over the many.

Democritus, despised though he was by Plato, possessed a similar view of moderation and harmony.  He was, however, a great defender of democracy, arguing that ‘Poverty in a democracy is as preferable to what is called prosperity under autocracy as freedom is to slavery.’ Harmony and moderation were to him means of protecting the democratic polity.  Plato reworked those very same values to make an ethical case against democracy.

We can read the difference between Plato and Democritus in one of two ways.  It might suggest that ethics and politics are unrelated, and that a similar view of what constitutes the good might lead to distinct views of the kinds of society that should embody the good. Or it might suggest that Thrasymachus is indeed right: that ethics are a means of justifying ‘the advantage of the established rule’; or rather, in Plato’s case, the advantage of those whom he thought should rule.

The questions of whether moral rules are objective or subjective, and of whether the idea of a good society is necessarily an expression of a struggle for power, have led to fraught debates throughout the history of moral thought and remain unresolved to this day.  The irony, though, is that while Plato despised Thrasymachus’ amoralism, the bleakness of his vision both of human nature and of human history led him to suggest that in reality Thrasymachus would win out. Deep down, all humans are, in Plato’s view, ‘beastly and savage’, possessed of ‘unnecessary pleasures and desires’ that are ‘lawless’. These lawless desires are oftentimes ‘held in check by the laws and by the better desires in alliance with reason’.  But it is ultimately a hopeless task, for neither laws nor reason can outwit for long the beast within.

Plato, like most of his contemporaries, believed in inevitable regress. ‘Everything that comes into being’, he wrote, ‘must decay.’ That is true of nature, it is true of societies, and it is true of souls.  His scale of societies from aristocracy to tyranny is not a scale of progress but of degradation. Each society inevitably disintegrates into a worse society, inexorably moving from one in which reason is king to one in which the basest of desires hold sway. In the end, for Plato, we can never escape the cave, and Thrasymachus is the true prophet, if not a philosopher king.