After escaping an assassination attempt earlier that morning, Cicero entered the senate under armed guard. It was 7 November 63 BCE, and the Roman Republic hovered on the brink of revolution. Catiline, the aristocrat behind the assassination plot, stood opposite. Faced with the man who had tried to kill him, Cicero gave one of the most powerful orations in all of antiquity: ‘O tempora, o mores!’(‘Oh these times! Oh the ways of men.’)

Central to Cicero’s speech is a provocative metaphor. The republic is a body, and Catiline a plague. Reasoning within this metaphor, Cicero prescribed a cure: to remove the disease, exile Catiline.

Cicero was utilising perhaps the most fundamental metaphor of political discourse: it runs through Thucydides’ account of the Peloponnesian war, anchors the political philosophy of Aristotle and Plato, and animates the rhetoric of Roman statesmen and Stoics. It re-emerges in the major political philosophers of the European tradition. Thomas Hobbes, John Locke, Jean-Jacques Rousseau, John Stuart Mill and many others deploy the metaphor to support a diverse range of arguments about human societies. We still speak casually of ‘heads’ of state and the long ‘arm’ of the law, of ‘backbones’, ‘heartlands’ and even ‘armpits’ of countries. Schools rally the ‘student body’, recruiters persuade people to join the marine ‘corps’, the press ‘corps’ or ‘corporations’ (all from the Latin corpus, for ‘body’).

The idea of political entities as figurative bodies doesn’t have a monopoly on metaphors for human collectives. Ancient Greek philosophers and historians often evoked the ‘ship of state’, an image that implies risk, a destination, and a crew and passengers with entangled fates; while those aboard have an interest in cooperating, they are not genetic relatives. The concept of a fatherland – the words ‘patriot’ and ‘paternal’ share Latin roots – goes further, joining citizens as metaphorical siblings with a common filial obligation to the state. But the body politic metaphor proposes something even more radical. Other people are not just related to you; they are you.

While Cicero succeeded in defeating Catiline and ultimately executing his co-conspirators, many historians argue that by establishing a precedent for the unconstitutional exile and murder of political opponents, he legitimised the very actions that would ultimately sanction his own death. After trying to heal the body politic, he was literally dismembered. On Marc Antony’s orders, Cicero’s head and hands were nailed to the public stage in the Roman Forum. The physician of the body politic could also be deemed a pathogen.

To describe the Ancient Roman, modern American or any other body politic as ‘diseased’ is now more often polemical rhetoric than considered diagnosis. But metaphors of political health and disease originally inaugurated a philosophical tradition that analysed political bodies in a systematic manner. For anyone interested in understanding politics today – its pathologies, symptoms and potential cures – these investigations constitute a vital but widely neglected resource. An essential recurring theme is the unsustainability of radical individualism: humans are fundamentally political animals, and the metaphor of the body politic is an ideal conceptual tool for realising that our health depends on the flourishing of a broader whole.

Political theorists in antiquity generally emphasised the primacy of the collective: Aristotle claimed that a man with no need of political community was either ‘a beast or a God’. In his vision, individuals derive meaning from participation in the political whole. By the early modern period, philosophers such as Hobbes and Locke had essentially reversed this idea, arguing that governments exist to preserve the property and safety of individuals. The whole derives meaning from the parts.

Today, radical individualism and growing political jingoism threaten to obscure the practice of reasoned debate about vital questions of liberty and community. From economic neoliberalism to deconstructionism, the political philosophies of the Right and the Left share a belief in the utopian powers of the liberated individual. This overemphasis on the individual has effaced the central questions at the core of the body politic metaphor: what is the purpose of political collectives, and how do these figurative bodies limit and enable individual flourishing?

In the Ancient Greek city-state, one motive for forming individuals into a collective body was the necessity of survival in war. In his history of the Peloponnesian war, Thucydides depicts the Spartan general Archidamus speaking to his troops before battle: ‘The best and safest thing of all is when a large force is so well disciplined that it seems to be acting like one man.’ Warfare relied on the integration of soldiers into a body of troops. If a sufficient number of individual soldiers acted as individuals loyal to nothing beyond self-interest, the survival of everyone would be jeopardised.

For Thucydides, the purpose of the political collective is primarily security and peace. Citizens who act as a unity are not only safer in battle, unrestrained individual desires also threaten the health of the body politic. Thucydides’ diagnostic descriptions of social collapse borrow directly from Hippocrates, the founder of Greek medicine. For instance, Thucydides uses the medical terminology of the body to describes how civil strife, stasis, ‘spreads’ through Greece.

A key early symptom of such political disease is linguistic. ‘The received value of names imposed for the signification of things became arbitrary,’ writes Thucydides of the outbreak of stasis in Corcyra. When names lack common referents, the social bonds that unite the community dissolve. To paraphrase the American philosopher John Dewey, the words ‘community’ and ‘communication’ are connected for good reason.

As a common understanding of what constitutes valour, wisdom and fear disappears, Thucydides describes how citizens prioritise their private interests by justifying even the most reprehensible actions with a degraded language of ethics. Soon, the individual elements of the body politic begin physically attacking one another, each faction utterly convinced of the righteousness of its actions. The body politic in Thucydides suppresses the latent violence and factionalism that civil warfare can awaken.

Plato was born into the world Thucydides diagnoses. His own family, aristocrats who participated in the oligarchic coup d’état at the end of the Peloponnesian war, were implicated in the mass executions of citizens. His mentor and idol, Socrates, was executed by the democrats after they seized power back from the oligarchs.

In his Republic, Plato invokes the central metaphor of the body politic in order to understand justice. Like Thucydides, he prioritises the body politic over the individual. The purpose of the city is to produce the flourishing of virtue. In Plato’s analysis, the ideal city is based on three separate classes: the philosopher-rulers correspond to Reason, the guardians to Spirit, and the producers and merchants to Appetite.

Cutting off the nose to spite the face is self-defeating only when they realise they belong to the same self

Plato uses the metaphor of a painted human statue to emphasise the necessary relationship between the parts and the whole. Even if the eyes of the statue might, taken alone, look best painted purple, what matters is the effect this would have on the entire composition. Justice, in both individual and political bodies, is an emergent property defined by the correct interrelations among the parts of the whole. If appetite usurps the role of reason, for example, it will make decisions that are literally partisan – designed to benefit only the part, not the whole body.

This is a powerful reframing of a basic political problem: if the eyes conceive of themselves not as eyes but as complete and self-sufficient individuals, they will naturally reject any political measure – any allocation of colour within his statue metaphor – that does not maximally benefit them. But if the eyes, or any other body part, actually conceive of themselves as fully integrated parts of the broader whole, such a position is incoherent. Cutting off the nose to spite the face appears self-defeating only when the nose and face realise they belong to the same self.

Many of Plato’s proposed methods for creating a just political body – the elimination of private property and radical censorship in the education of the guardians – are impractical and dangerous, as philosophers from Aristotle to Karl Popper have argued. While Plato prioritises the authority of the state, he shows us that we must have a definition of justice that defines our obligations and responsibilities to one another. And though Plato almost certainly argues for a hierarchy of classes, he teaches us that our own individual flourishing exists in name alone if it is antithetical to the interests of the body politic at large. Plato is often accused of espousing a form of proto-totalitarianism, but his emphasis on the good of the larger body politic also suggests more progressive measures: denying ‘purple’ to the eyes could mean refusing tax breaks to corporations, not denying military guardians free access to literature.

Radical individualism aspires to paint the whole world purple. From this blinkered standpoint, an individual who lacks school-age children or possesses a generous private pension would have no reason to support public education or social security benefits for the elderly. Both would constitute allocations of colour that do not appear to maximise a narrowly construed individual advantage. Plato’s metaphor reminds us to seek beauty and harmony from a zoomed-out vantage that considers the broader whole. Social welfare, at its foundation, demands a conceptualisation and defence of the body politic.

Aristotle’s vision of political life combines Thucydides’ realism and Plato’s idealism. He acknowledged that humans formed themselves into political bodies to survive, but he did not believe that this fully accounted for the purpose of the city-state. ‘While it comes into existence for the sake of life, it remains in existence for the sake of the good life,’ Aristotle writes in the Politics. The state does not just secure life but renders it rich and meaningful. National parks, orchestras, symphonies, museums and libraries are some of the descendants of this idea.

While Aristotle does think that the locus of happiness must be the individual – the whole cannot enjoy happiness unless most individuals do – he still assigns primacy to the whole. Just as a hand is no longer really a hand if the body to which it was previously joined has been destroyed, so too does the individual depend on the body politic: ‘For although it is worthy to attain [flourishing] for only an individual, it is nobler and more divine to do so for a nation or city-state.’

Radical individualism facilitates a convenient forgetting of the ligaments that bind us to others

Aristotle argues that true individual flourishing requires a collective political life, but he excludes slaves and women from civic participation. It is easy to dismiss him on the grounds of his facile defence of slavery, but it’s more difficult to face the questions he poses about our own world. To what extent do we still treat people as ‘animate objects’ – Aristotle’s chilling description of human slaves? To what extent is the liberty of the Silicon Valley CEO or the tenured professor studying Aristotle predicated on the domination of workers?

The body politic metaphor raises these essential questions, and it also suggests answers: ‘incorporating’ others into our figurative bodies and strengthening connections within the body so that their pain is felt as our own. This would make visible and visceral one of the dominant manifestations of political and economic exploitation: the flourishing of vibrant urban centres that depend on the suffering of impoverished and displaced communities. As inequality drastically increases around the world, radical individualism facilitates a convenient forgetting of the ligaments that bind us to others.

In Plato’s image, the eyes’ deprivation of a daub of pretty colour seems a small sacrifice, but ranking the political whole above its constituent parts can sanction much more severe suffering. The Roman Stoic Epictetus wrote that, just as a foot ‘does not stand by itself’ and must at times ‘walk in the mud … tread on thorns and sometimes even be cut off for the benefit of the whole body’, so too the individual man is only ‘a part of a whole’. Thus, men might have to suffer sickness, sea voyages, even death – the civic analogues of thorns, mud and amputation.

Perhaps no philosopher more forcefully argued for the necessity of the collective than Hobbes, the first English translator of Thucydides. Hobbes sought to understand the way in which free individuals driven by self-interest could form stable collectives. Confronting the devastation of the civil wars in England in Leviathan (1651), he follows Thucydides in diagnosing disease in the body politic by analogy to human sickness, comparing epilepsy to civil war, and underscoring how these convulsions cause words to lose their standard meanings. But Hobbes inverts the paradigm of the ancient body politic analogy. Whereas Plato in the Republic compares the state to the individual, Hobbes analogises the individual to the state.

For Hobbes, free individuals live in a natural state of conflict and war. They ‘naturally love liberty’ but this entails the desire for the ‘dominion over others’. Without a social contract, humanity is limited to a zero-sum struggle for finite resources, what Hobbes describes as a ‘war of everyone against everyone’. We choose the ‘covenant’ of the state in order to ensure our ‘preservation’ and a ‘contented life’. And, while all forms of government involve the loss of individual liberty, only monarchy secures the greatest stability and peace because it is least subject to alteration.

Like Hobbes, Locke bases much of his political reasoning on an extended analogy between states and bodies. Yet while Hobbes defended absolute monarchy, Locke wrote his Second Treatise of Civil Government in part to justify the Glorious Revolution of 1688, which strengthened Parliament and resulted in the abdication of James II. For Locke, a body politic forms when every individual consents to be bound by the same impartial laws. The king cannot, by analogising himself to the brain, claim exemption from the laws that govern any other ‘part’ of the body. Though Locke is still writing within the body politic metaphor, he is pushing at its limits: the hierarchy implied by the biological structure of the body is dissolving into a more horizontal model defined by consent of the governed, and the universal application of law.

Hobbes argued that a strong monarch provides salvation from a state of nature; for Locke, however, rule by a monarch is worse than a state of nature:

For then mankind will be in a far worse condition than in the state of nature if they shall have armed one or a few men with the joint power of a multitude, to force them to obey at pleasure the exorbitant and unlimited decrees of their sudden thoughts … without having any measures set down which may guide and justify their actions.

The prospect of a deranged tyrant unchecked by law combines the dangers of humans’ worst natural impulses with the powers of collective action.

Only the associative body politic, whose nerves are connected by active debate and assembly, is truly human

Hobbes and Locke discern different dangers, but both share a largely defensive concept of government. Locke grants political bodies only a limited goal: ‘The great and chief end, therefore, of men uniting into commonwealths, and putting themselves under government, is the preservation of their property.’ Absent from this vision is Aristotle’s idea that the basic purpose of political life is human flourishing, not merely the provision of security and the protection of private property. It’s as if Hobbes and Locke were content to define the health of the body politic only by the absence of disease.

Radical individualism today retains this highly circumscribed conception of government’s role; the body politic – above all – serves to protect the safety and the property of the individual. This is exemplified in a line made popular by the US president Ronald Reagan: the nine most terrifying words in the English language are: ‘I’m from the government and I’m here to help.’ It is a radical philosophy that suggests the political collective should have no role beyond the protection of the individual. Furthermore, it is one currently invoked to defend the rising hegemony of a tiny oligarchic elite that ultimately depend on a vast underclass. While security and some protection of private property may be necessary preconditions for survival, they are not sufficient for human flourishing.

In The Social Contract (1762), Rousseau argues that a healthy body politic founded on inequality is impossible: ‘as soon as there is a master, there is no more sovereign, and the body politic is destroyed forthwith.’ He deploys a reimagined conception of the body politic to argue against Hobbes’s monarchism:

When scattered men, regardless of their number, are successively enslaved to a single man, I see in this nothing but a master and slaves, I do not see in it a people and its chief; it is, if you will, an aggregation, but not an association; there is here neither public good, nor body politic.

To extend his analogy, the aggregate body – because it is based on inhuman relationships of inequality and domination – is only a hierarchical assemblage of discrete members. Rousseau paints a grotesque picture of this political arrangement: ‘It is as though a man were to be composed of different bodies, the one having eyes, another arms, a third feet, but not furnished with more than a single set of organs.’ Only the associative body politic, one whose nerves are connected by active debate and assembly, is truly human. This is Rousseau’s body politic, one in which ‘Citizens … are at one and the same time both sovereign and subject.’

Radical individualism remembers only the first half of Rousseau’s philosophy: ‘Man is born free; and everywhere he is in chains.’ Today, billionaires build bunkers to survive the apocalypse and dream of libertarian utopias on Mars. Meanwhile forms of identity politics stress the liberating power of joining ever smaller micro-affinity groups. Both seek to cast off their chains. But Rousseau also stresses that ‘if there were not some point in which all interests were identical, no society could exist.’

The body politic metaphor continues to shape our political discourse today. Are immigrants pathogens, breaking across the skin barrier of our borders? Or are they essential infusions of new life into the political bodies of Europe and the US? The language used by news corporations for protest movements and epidemic diseases is strikingly parallel. Just a few years before journalists around the world began reporting on the Ebola ‘outbreak’, The New York Times in August 2013 described revolutions in the Middle East as the ‘outbreak of the uprisings optimistically known as the Arab Spring’. Revolutionary movements, refugees and maligned political leaders are regularly treated as disease.

This dangerous use of the body politic is as old as the metaphor itself. In the sacred Indian text the Rigveda, human sacrifice creates the Universe and society:

When they divided the Man, into how many parts did they disperse him? What became of his mouth, what of his arms, what were his two thighs and his two feet called? His mouth was the brahmin, his arms were made into the nobles, his two thighs were the populace, and from his feet the servants were born.

When servants become feet and dissenters become pathogens, many intellectuals rightly feel a deep suspicion for the body politic language. Yet seeing others and ourselves as parts of a larger metaphorical body reminds us of the crucial fact of our interdependence, helping to rescue us from what Hannah Arendt described as ‘the weightless irrelevance’ of our individual affairs. Meditation on the meaning of the body politic from Thucydides to today reminds us that the individual is fundamentally a component of a collective political organism. To avoid becoming an agglomeration of fractured and easily manipulated individuals and micro-affinity groups, we must return to the difficult task of negotiating a public defence of the body politic. If we fail to voice a collective vision of the body politic today, we are destined to pay an extreme price for our individualism: the loss of a world in which it is worth being free.

The current political crisis is multifactorial, but three key variables are historically high levels of income inequality, impending ecological collapse, and the defunding of higher education – particularly in the humanities. Higher education and politics have largely abandoned discourse on these problems to the ideology of unfettered individualism. Thus, central human questions – traditionally investigated within the humanities – are largely left to TED talks and political memes.

The questions raised by Plato, Aristotle, Hobbes, Locke and Rousseau should be studied and debated seriously by the body politic at large. Only in committing to a discourse that avails itself of the insights of history and philosophy to seriously consider the tensions between individual and collective life will we be able to address the very real plagues of humanity. As Dewey wrote in 1935, it is imperative ‘to assume the responsibility for making it clear that intelligence is a social asset and is clothed with a function as public as is its origin, in the concrete, in social cooperation.’ This is to bring the debate back to the body politic; it is to make discourse live. For, as Mill wrote in On Liberty (1859), however true an opinion might be, ‘if it is not fully, frequently, and fearlessly discussed, it will be held as a dead dogma, not a living truth.’