Natural Reason and the Ethical Foundations of European Law
Revue européenne du droit
Most defences of the European Union are consequentialist. They say that for this or that reason the EU serves interests in prosperity or security. The most common attack on the European Union, however, is not consequentialist but based on a constitutional theory of ‘popular sovereignty’. If you believe that popular sovereignty is the ground of a constitutional order, you may find the European Union’s claims to have a say on domestic government questionable. This criticism is very effective because political institutions are normally justified on the basis of ideas of right and wrong, not on their potential consequences. Nevertheless, the ‘popular sovereignty’ argument against the EU is the result of a serious misconception about the nature of constitutions. I sketch here an alternative argument, which explains the legitimacy of transnational institutions and the European Union on the basis of constitutional justice and equal citizenship. The argument continues a long – and in my view fruitful – tradition of legal scholarship, which defends the constitution and the ideal of the rule of law not merely on the value of procedures but also on the basis of ‘natural reason’.
The Problem with Popular Sovereignty
A constitutional theory of ‘popular sovereignty’ justifies political institutions on the basis that they are an expression of a people’s ‘will’. Constitutional lawyers often rely on ‘popular sovereignty’ because it is both strictly procedural and strictly conservative: legislation produced by the current majority can be seen to be fully justified, whatever its content. Some take this to extremes. Carl Schmitt thought that the people’s will was the entire meaning of constitutional law. More careful thinkers say that a state is legitimate only if its people fundamentally approve of its lawful decisions.
The doctrine of popular sovereignty has always been a precarious constitutional theory, however. Law and sovereignty are in permanent tension. The original scholars of sovereignty knew, but some contemporary constitutional lawyers seem to have forgotten, that political sovereignty’s demands are all-consuming. They do not allow for higher law or judicial oversight. The very idea of a sovereign person or body entails that political power is above the law. This is why monarchs like it. The modern theorists of sovereignty, and especially the British legal theorists Bentham and Austin agreed on the absolute nature of political sovereignty. Their follower A. W. Dicey, rather hopefully, believed that it can be exercised by Parliament, a representative body and not the Executive (even though by the time he wrote the leader of the Executive normally controlled Parliament through party discipline). As many other scholars have noted, the British idea of absolute ‘parliamentary sovereignty’ opens the way towards ‘elective dictatorship’. In a related way, however, a simplistic account of sovereignty also challenges international law, because it presents our commitments to other nations as usurpations. This is a different problem, but it is equally important.
I think that the answer to both problems is a better understanding of the nature of a legal order and of the way in which law is a practice of judgment and not merely a social event or an expression of ‘popular will’. Constitutional law and international law are not created by the will of the people or a state. Like all law they are constructions of reason in light of universal features of the human experience, or in the language the Romans used, ‘natural reason’.
Natural Reason and Civil Law
The Greek and Roman republics sought to break down sovereignty and the traditional power of Kings. We are not so different from them. The challenge of constitutional design for contemporary republics, be they in the United States, France or India, is to break down power and organise it into offices that balance each other out, in order to avoid the twin dangers of oligarchy or mob rule. Sovereignty and government power are thus different things for a republic. Constitutional law is in effect the very denial of absolute sovereignty: it is government under the law, where every decision is accountable in light of public laws. The emergence of constitutional law in Europe in the course of the nineteenth century has been a process of changing the old meaning of sovereignty into something entirely new and perhaps inconsistent with its old meanings. As soon as we create a legal basis for government in the way of constitutional law as higher law, and not merely as a programmatic statement, sovereignty is under threat from the very institutions that exercise it. Following some of the insights of Plato, Aristotle and Cicero, the Roman law tradition clearly establishes that a community based on the rule of law has no use for absolute power at any level.
Let us recall that the Roman Republic relies on the legend of the expulsion of the last King, the tyrannical Tarquinius Superbus, or ‘Tarquin the Proud’. Similar events of rebellion against tyranny marked the creation of the French and American republics. And the intellectual process is very similar, irrespective of the historical differences. How can you reconcile sovereignty with the power of a judge to enforce a constitution against a Consul or a Prime Minister or against a Parliament? It is thus no coincidence that all republics celebrate public laws and cultivate the ideals of the rule of law. Similarly, all absolute monarchs and all authoritarians trivialise the idea of the rule of law by turning into a purely formal rule by law.
Confusion about sovereignty, however, has an equally significant effect on our understanding of international institutions. The absolute sense of sovereignty has great trouble accommodating the cooperation of states. Bodies created through international treaties, such as the European Union, the World Health Organisation (WHO) or the International Telecommunications Union (ITU), may appear to act without legitimacy when they are merely exercising their delegated powers. Every time a transnational law is made, some power is removed from domestic political institutions. A government, for example, cannot ban EU nationals from selling insurance under the rules of the European Union, cannot ignore the risk of a pandemic under the rules of the WHO and cannot allocate radio spectrum or determine satellite orbits unilaterally, under the rules of the ITU. But what if such banned rules were the overwhelming desire of a domestic majority (or of its leaders posing as the majority)? It appears then that under the doctrine of ‘popular sovereignty’ any international commitments are illegitimate and ‘undemocratic’. If we are to defend and vindicate transnational law, we need to expose these fallacies of sovereignty. But we are also compelled to ask: what is to replace it?
At the root of the mistake lies the premise that everything about law is the result of somebody’s ‘will’, which opens the way to ‘popular will’ as the only legitimate option. That many legal philosophers believe that law derives entirely from the positive will of some official, is partly the result of the battles of the nineteenth century for law reform. Radical lawyers sought to undermine and destroy the main argument for established hierarchical and oligarchic legal structures. The conservative argument was that these structures, awful and anachronistic though they seemed, were based on ‘the wisdom of the past’, as eloquently put by William Blackstone. Blackstone’s nemesis in England was the brilliant polemicist Jeremy Bentham, who exploded Blackstone’s constructions by exposing them to a rigorous test of both reason and experience. The movement of thought that Bentham and other reformers started is called ‘legal positivism’. Just like Blackstone insisted that all law was reason, similarly Bentham responded that none of it is. Driven by his polemical zeal, Bentham turned traditional legal scholarship on its head. The doctrine of legal positivism therefore says that the law is exclusively made by the power or political authorities and nothing else. The excessive zeal was perhaps necessary, in order to promote legal reform in sclerotic Britain at the time, but it went too far.
Outside the heat of political battle, European legal philosophers and practitioners understand that at the centre of our legal concepts lie things we cannot deny: the core of law, private, public or international, derives from reasons that are common to all thinking persons. It is wrong to call this ‘natural law’, but it may be appropriate to call it ‘natural reason’. This idea is currently unfashionable, but it has a very long and distinguished history.
The Byzantine lawyers that compiled Justinian’s codification in the sixth century organised their thinking around two central ideas. They had in mind, first, the idea of a law of reason, or ‘ius gentium’ and, second, that of civil law, the socially made law of a city, or ‘ius civile’. A judge or scholar was supposed to rely on both in order to reach an appropriate judgment or conclusion. The Digest begins with the words of Ulpian, who distinguishes in Latin ius (as ‘law’) and lex (as ‘statute’), and tells us that law, in the broader sense of ius, is closely connected with the art of judging what is good or just. Ulpian quotes with approval the definition of Celsus, namely: ‘the law [ius] is the art of goodness and fairness’. Ulpian goes on to say that the main actors in law are its ‘priests’, the professional lawyers: ‘Of that art we [jurists] are deservedly called the priests. For we cultivate the virtue of justice and claim awareness of what is good and fair, discriminating between fair and unfair, distinguishing lawful from unlawful, aiming to make men good.
For the Romans the law was an art, or a practice that humans did together. This art involves distinguishing among good and bad arguments on the basis of the parties’ advocacy and with the support of the best available evidence. But the Romans were very clear that most of law was made by society and its institutions. Humans created law in response to their needs and aims. The Romans did not believe in some fully prescriptive ‘natural law’, perhaps fully formed and ready to apply in the way of a blueprint (a caricature often polemically deployed by modern legal positivists). Law was mostly ‘civil law’ made for each state according to its own lights. Civil law, as Ulpian himself was very careful to observe, is based on a positive act of legislation in light of natural reason and the dictates of ‘ius gentium’, the law of nations. Ulpian further is also quoted as saying that knowing the law involves knowing of both God’s and man’s affairs: ‘Justice is a steady and enduring will to render unto everyone his right. 1. The basic principles of right are: to live honourably, not to harm any other person, to render to each his own. 2. Practical wisdom in matters of right is an awareness of God’s and men’s affairs, knowledge of justice and injustice’.
What does it mean to say that natural reason may guide legislation and legal judgment? There are, obviously, very many philosophical questions raised by this idea. Yet, Justinian’s Institutes, the introductory textbook that the same Byzantine lawyers put together in order to assist in the reading of the Digest, had no problem applying it in practice and offering us some excellent examples. The textbook says that natural reason requires that any wild beasts, fish and all animals belong to the first person to capture them, ‘for natural reason gives to the first occupant that which had no previous owner’. Furthermore, natural reason requires that when one man makes anything with materials belonging to another, owns the resulting product, e.g. wine, honey or oil, if the thing made cannot return to the original materials. And if a man plants another man’s plant in ground belonging to himself, then the owner of the ground owns the tree. And finally, natural reason also requires that if a person has bona fide purchased land from another who turns out not to have been the owner, the deceived buyer can still keep the fruits of the cultivation of that land. All these examples have a common theme that natural reason determines their outcome under rules of fairness and justice (and not the natural inclinations that we share with the other animals). A sense of fairness and justice appears to be at the heart of these judgments about how to act.
The idea of an inherent or natural reason to legal judgment is not just Roman. It has been equally present in English law. In Ashby v. White, a famous case in the common law world which was decided in 1703, the Chief Justice, Lord Holt, accepted the claim of a voter obstructed from voting by the returning officer against those prevented him from entering the polling place. The legal issue in the case was whether the claimant could bring a claim before the courts at all, or if the case was subject to the exclusive jurisdiction of Parliament, as a matter relating to elections. Lord Holt said that “if the plaintiff has a right, he must of necessity have a means to vindicate and maintain it, and a remedy if he is injured in the exercise or enjoyment of it; and indeed it is a vain thing to imagine a right without a remedy; for want of right and want of remedy are reciprocal.” And he then went on to explain the rationale of this conclusion on the basis of ‘the reason of the law’; which requires that wherever there is a right, there ought to be a remedy. Conveniently for those of us who wish to stress the analogy, he used the same Roman phrase for that: ‘ubi eadem ratio, ibi idem jus’.
We should not exaggerate the significance of this judgment, which has had limited effect in English law. In terms of the electoral law of the United Kingdom the case had no impact at all. It did not elevate the right to vote into some kind of constitutional right, nor did it change the practice of having electoral disputes go exclusively to the petition jurisdiction of Parliament. John Baker notes that this was a claim that shows ‘an affinity to more conventional nuisance and disturbance actions’. Moreover, the exclusive jurisdiction of Parliament was changed only by an Act of Parliament in 1868 whereby electoral disputes could be taken to a special procedure at the High Court. Yet, ideas of basic requirements of justice are ever present in both Roman and Common law.
They are also equally prominent in European Union law, which has brought together the practices of both the civil and the common law worlds in a unique and fertile synthesis. Here the idea of ‘ius gentium’ appears in the guise of legal principles that are ‘common in the constitutional traditions of the member states’. This is another way of referring to the Roman ius gentium, or ‘the law of nations’. Here too the premise that a substantive right entails a remedy and must be protected by the courts is also taken to be something like a principle of natural reason. The Court of Justice of the EU routinely affirms that the right of a person to access institutions of justice in order to seek a remedy is part of the ‘constitutional traditions common to the Member States’ and is also enshrined in the Treaties. Advocate General Fennely, just like Lord Holt three hundred years earlier, explicitly referred to the Roman principle of ‘ubi ius, ibi remedium’ in support of the general EU principle of effective protection (which is also supported by Article 19 TEU and Article 47 of the Charter of Fundamental Rights). So the idea that natural reason determines legal judgment is very much alive in modern law.
The Act of Foundation
We can now return to the question that started these reflections. What is to replace the argument from political sovereignty and the absolute authority of the will of the people? We see now that the two positions are not symmetrical: legal positivists deny the role of natural reason in the law, because they say that all law is made by a conscious decision of someone sufficiently powerful or influential. By contrast, those who believe in natural reason need not deny that civil law is human law, made for our current circumstances by someone sufficiently powerful or influential, as we saw in the case of Roman law. It is just that for the ‘natural reason’ view, law must meet further rational tests before becoming civil law in the proper sense. Civil law, in that usage, must have some social foundations, but these foundations are not to be taken to be a simple causal chain. Law is not caused to exist by the action of some original founder. It is created in the course of practical deliberation about what to do. This introduces a distinction in two senses of ‘founding’, one causal and the other deliberative. This distinction needs a lot more to become clear. I can only offer a preliminary clarification. What exactly is a ‘deliberative’ foundation?
The major contributors to our understanding of a constitutional foundation are not the practising lawyers this time. They could not be, since, with the exception of the canon law of the Christian churches, there was not much public law to practise during much of Europe’s legal history. Modern constitutional thinking emerges with the philosophers of the Enlightenment. These innovative philosophers brought a message of social liberation based on the idea that the institutions and hierarchies of all human communities were the result of human actions and not divinely ordained or permanent features of our nature. As a result, all human institutions had to respect ethical principles based on natural rights. The philosophers arrived at the principles of natural reason through a more circuitous route than their Roman forbears, via the idea of the ‘social contract’. The social contract was an idea of political foundation that sought to replace the original myths of absolute monarchy. For Locke and his many followers, citizens have natural rights against their leaders. Political leaders, just like the Romans believed, had correlative duties to promote the good of the commonwealth. People were not bound to obedience towards their King or other bearer of ‘political sovereignty’, but were bound to each other on the basis of an act of reciprocal limitation of powers or rights.
The force of these ideas is nowhere more eloquently set out than in the debate between Edmund Burke and Thomas Paine on the French Revolution. Burke establishes the right of Kings in the history of a political community, whereas Paine establishes the right of citizens to determine their government democratically on the natural rights of man. The argument can be easily misunderstood, however. The act of foundation in a social contract and natural rights that Paine, and before him Locke, Rousseau and Kant, had in mind is not a historical event. It is a moral judgment made solemnly and publicly because of natural reason.
The Constitution as an Ethical Project
I think that the most powerful philosophical argument for constitutional law as a project of practical reason is found in Kant’s writings on law and the state. Here what the Romans called ‘natural reason’ is renamed and elaborated upon as ‘pure practical reason’. In the Metaphysics of Morals Kant offers, thus, a comprehensive argument for the synthesis of ethical and political duties under the ‘moral law’ emanating from pure practical reason. His argument is not always clear but we can summarise it for current purposes in the following way. If natural reason tells us that wild animals must become the property of the first person that takes possession of them, as the Roman lawyers said, then reason may also give assistance in other practical matters. It may for example, tell us that there must be some public recognition of property rights, to secure our ordinary possession of things and land. And if there is to be private property, then there must be a law of agreements or contracts by which we transfer property from one person to another. And if there is to be property and contract, then we need courts and other public institutions, making sure that the substantive rights emerging through private transactions are fairly enforced.
These are the steps that Kant makes to establish the moral meaning of a legal order or, in Kant’s words, the ‘civil condition’. They are both steps of fact and steps of reason. When I find myself claiming the fish that I have retrieved from the river, as a result of my actions in light of civil law and of natural reason, similarly, I may find myself having duties of citizenship to the state where I happen to be, both because of natural reason and because of the constitution that is in place here, where I happen to live. In effect, Kant argues that equal citizenship is a universal presupposition of all law, properly enacted. In the Metaphysics of Morals he wrote: ‘Every human being has a legitimate claim to respect from his fellow human beings and is turn bound to respect every other. Humanity itself is a dignity; for a human being cannot be used merely as a means by any human being (either by others or even by himself) but must always be used at the same time as an end.’ He also said that a universal requirement for defending human dignity is setting up a ‘civil condition’ or in other words, establishing institutions of ‘public right’ that protects everyone’s rights. This means that the very idea of a constitution presupposes a set of public rules encompassing all as free and equal citizens.
When the French revolutionaries tried to make sense of the idea of equality and rights in order to destroy the ancient privileges of the landed gentry, they modified sovereignty so that it should be subject to natural rights. The first three articles of the Declaration of Man and Citizen of 1789 concern, first, equality, second, the rights of liberty, property, security and ‘resistance to oppression’ and, third, the principle of popular or ‘national’ sovereignty. Freedom and equality of individuals take priority. Sovereignty follows and is conditional on them. The constitution is not, therefore a matter of the free discretion of the people that make it. Nor is the decision to have or not to have a constitution as higher law open to us. The 16th article states: ‘A society in which the observance of the law is not assured, nor the separation of powers defined, has no constitution at all’. These matters belong to the core of a constitution and cannot be omitted from it. This document was both a foundation of a new constitutional order and, at the same time, the declaration of truths that are permanent constructions of reason. The constitution signifies both change and permanence, a new departure and the return to old truths. Just like the private law of property in Roman law, the act of the creation of law is effective and marks a new political beginning, precisely because it is based on permanent truths of reason.
In Theory and Practice Kant addresses this complexity when he says that the social contract binds ‘every legislator to give his laws in such a way that they could have arisen from the united will of a whole people and to regard each subject, insofar as he wants to be a citizen, as he had joined in voting for such a will’. This applies to the constitutional legislator as much to the ordinary legislator and binds both process and result. A constitution, therefore, is a moral idea: ‘Public right is therefore a system of laws for a people, that is, a multitude of human beings, or for a multitude of peoples, which because they affect one another, need a rightful condition under a will uniting them, a constitution (constitutio) so that they may enjoy what is laid down as right’. All legal foundations rely on ethical and moral duties unearthed by human reason.
So when Hannah Arendt reflects on the act of foundation of a new commonwealth by the American founders and the French revolutionaries in her On Revolution, she notes that ‘it is in the very nature of a beginning to carry with itself a measure of complete arbitrariness’. But she concludes her overview of the thinking that supported the revolutions with the observation that ‘what saves the act of beginning from its own arbitrariness is that it carries its own principle’. Arendt did not explain very clearly what that ‘constitutive’ principle is, but in my view this is the moral recognition that we are free and equal persons with mutual duties of respect, or what I will call Kant’s ethical theory of the state. Modern philosophers of law have offered much detail and depth to this insight. In Between Facts and Norms, Jurgen Habermas explores in great detail Kant’s ‘concept of legality’, which lies between facts and norms. Offering a rival, ethically richer view, in Justice for Hedgehogs, Dworkin offers a synthesis of ethics, morality and political philosophy on the basis of what he calls ‘Kant’s principle’, namely the position that ‘a person can achieve the dignity and self-respect that are indispensable to a successful life only if he shows respect for humanity itself in all its forms’. Seen in this light, the constitutional beginning or ‘foundation’ is not a beginning in a causal or temporal sense, as implied by Kelsen and Hart and other legal positivists, who saw the bedrock of the legal system in some kind of event of consensus.
For the ethical view as set out by Kant and others the legal order rests on a series of moral judgments, that we make when we assess the institutional framework around us. A new constitution emerges not when it is announced by its makers, but when it takes its place within a generally known story of collective deliberation, persuasion and disagreement about our ethical life. In the most successful case, a constitution communicates to all that our deliberation has reached a temporary pause, so that we now have a principle of action: this is how we choose to be governed. It is what we say to each other as equal citizens of a commonwealth, in the same way that a maxim of action is the personal ground of an individual’s action. I stress that this does not apply in the same way to all constitutions. Some constitutions are defective, either because the procedure of their creation was unfair or because their substantive principles are unjust. Their legitimacy may be weak or non-existent. But in the case of a successful constitution, its requirements are not orders, or commands that demand obedience, but are statements of a deliberative act of judgment based on reasons. As with all acts of willing, willing a constitution is not a completely new beginning. Since the foundation of a new constitutional order is an ethical commitment from one citizen to another, it is also a deliberative engagement with our past. A successful constitution carries its own principle, as Arendt said.
The European Union as an Ethical Project
What does such this sketch of an ethical account of the constitution mean for European Law? First, it rules out purely procedural accounts of the constitution, such as those based on ‘popular sovereignty’ and by extension, purely transactional accounts of international law and institutions as the unlimited ‘will’ of states. Second, it rules out interpretations that are strictly statist, i.e. they see the EU as competing with the member states for ‘sovereignty’. For the popular sovereignty view, the constitution as the work of a people’s will is strictly one dimensional: there cannot be any ‘higher’ law, since any later expression of the people will overrule the earlier one. Any international commitments the popular will makes will eventually result in an ‘external’ imposition. This is how the Eurosceptics in Britain view the European Union: even though the EU treaties – designed to be ‘higher law’ – were freely entered into by successive UK governments, while the UK was a member, the Eurosceptics constantly complained of ‘foreign’ control and of a supposed ‘democracy deficit’ because decisions were taken collectively by all the member states and not purely in London. The ethical account of the constitution explains that some pre-commitments are not only legitimate but essential for a just ‘civil condition’. Having a constitution as higher law is, in fact, a requirement of natural reason. So constitutional standards are designed precisely to limit the powers of occasional majorities. Similarly, we can say, the EU is just another self-imposed constraint on our legislative powers. It is ethically justified because it allows us to cooperate with our neighbours in order to ‘manage our interdependence’, to use Steve Weatherill very suggestive phrase. As Weatherill shows in his magisterial analysis, the European Union does not make the claims to federalism that some authors believe it does. EU law is part of the law of nations, not constitutional law.
We then see that our international commitments and the European Union Treaties may also ‘carry their own principle’. If they are entered into freely on the basis of equality and reciprocity and if they promote cooperation without compromising internal democracy and the rule of law, they will assist us in complying with our ethical duties to one another.
The European Union may thus be a more advanced ethical project, one that supplements and amplifies our constitutional government. It is our considered response to our tyrannical past, that defined by the crimes of Nazism and fascism and of those who stood silently by. But the EU’s primary aim is not, at least not directly, democracy and the rule of law, but peace among nations. The EU does not compete with member states and is not seeking to replace them. It does not create a new civil condition replacing the old ones. It is instead a union of civil conditions or, in the terminology that I prefer, a union of peoples.
Natural reason plays a part there too, however. As Kant saw very clearly, all republics have a duty to recognise the moral standing of other states and their citizens. This creates the basis for fairness in international law and for a special kind of law which he called ‘cosmopolitan’ law, the law between a state and the citizens of other states. Just like the constitution, transnational law is the work of equal citizens, this time responding to the ethical challenges of peace. It is another way we have of showing respect for each other’s humanity.
 I cannot argue for that point here. I said more about it in P. Eleftheriadis, Legal Rights (Oxford: Oxford University Press, 2008).
 A historical process described well by D. Acemoglu and J. Robinson, The Narrow Corridor: States, Societies and the Fate of Liberty (New York: Viking, 2019).
 I explain this in more detail in P. Eleftheriadis, ‘Power and Principle in Constitutional Law’ 45 Netherlands Journal of Legal Philosophy (2016) 37-56.
 A. Watson (ed.), The Digest of Justinian, Volume 1 (Philadelphia: Penn Press, 1998) (I. i. 1, § 1), p. 1. The Latin text is: ‘ius est ars boni et aequi’.
 He writes: ‘And so whenever to the common law we add anything or take anything away from it, we make a law special to ourselves, that is, jus civile, civil law. 1. This law of ours, therefore, exists either in written or unwritten form; as the Greeks put it’; Digest, I. i. 1, § 6, p. 2.
 Digest, I.i,1 § 10.
 Justinian, Institutes, translated with an introduction by P. Birks and G. McLeod (London) Duckworth, 1994) 2.1.12.
 Justinian Institutes, 2.1.25.
 Justinian Institutes, 2.1.31.
 Justinian Institutes, 2.1.35.
 Ashby v. White (1703) 92 ER 126. Holt’s opinion was an initially dissenting opinion which was upheld by the House of Lords on appeal.
 J. Baker, An Introduction to English Legal History (London: Butterworths, 2002) 431-432.
 Until courts got involved and voting became secret by way of the Ballot Act 1872, elections in England were highly irregular and in many cases corrupt.
 See for example Case C-279/09 DEB Deutsche Energiehandels- und Beratungsgesellschaft mbH v Germany  ECR I-13849 at par. 28. See also Opinion 1/2009  ECR I-1137, par. 70 and Opinion 2/13  ECLI:EU:C:2014:2454, par. 1174.
 Case C-18/94 Barbara Hopkins v. National Power plc  ECR I-2281, Advocate General’s Opinion at .
 I. Kant, Metaphysics of Morals in Practical Philosophy, edited by Allen Wood and translated by Mary Gregor (Cambridge: Cambridge University Press, 1996). For very clear accounts of the Kant’s argument see A. Ripstein, Force and Freedom (Cambridge, Mass.: Harvard University Press, 2011), B. S. Byrd and J. Hruschka, Kant’s Doctrine of Right: A Commentary (Cambridge, CUP, 2010) and J. Ebbinghaus, ‘The Law of Humanity and the Limits of State Power’ 10 Philosophical Quarterly (1953) 14-22.
 Metaphysics of Morals, 6:462
 I. Kant, ‘Theory and Practice’ in Practical Philosophy, ed. by Allen Wood, 8:297.
 Metaphysics of Morals 6:311.
 H. Arendt, On Revolution (London: Penguin, 1977) 198.
 Ibid, 205.
 J. Habermas, Between Facts and Norms: Contributions to a Discourse Theory of Law and Democracy, trans by W. Rehg (Cambridge, The MIT Press, 1996) 28.
 R. Dworkin, Justice for Hedgehogs (Cambridge, Mass.: Harvard University Press, 2011) 19.
 I here summarise some of the arguments I made in my recent book, P. Eleftheriadis, A Union of Peoples: Europe as a Community of Principle (Oxford: Oxford University Press, 2020).
 See S. Weatherill, Law and Values of European Integration (Oxford: Oxford University Press, 2016).