Robert Alexy is perhaps Germany's leading theorist of law and of constitutional rights. His writings possess a broad significance for liberal democracies everywhere. The book consists of 21 tightly integrated essays, all of which have been published before but some of which are published here for the first time in English. Together, they offer the reader a systematic theory which brings to completion Alexy's formidable contribution to legal thought. The book ranks as a major contribution which undoubtedly merits careful scrutiny from anyone with an interest in jurisprudence, human rights or legal argumentation.

In this review, I will not endeavour to summarise the contents of a complex book. Alexy's work is all too often discussed within the narrow context of contemporary debates between legal positivism and anti-positivism. But Alexy's most fundamental theme is law's basis in reason. To appreciate the real importance of his contribution, it is helpful to set it against the background of Germany's transformation and reconstruction during the second half of the last century. Only at the end of my review will I address the narrower issue of Alexy's anti-positivism by examining an argument that has been prominent in the Anglo-American response to his work.

Alexy was born in Germany in 1945, at a time when his country needed to make a decisive turn away from much of its past: not only the barbarism of the Third Reich, but also the juridical and philosophical assumptions that had rendered the Weimar Republic vulnerable to that barbarism. A stable liberal democracy needs more than appropriate institutions: it also needs a framework of ideas within which those institutions can function appropriately and be defensible to reason. In addition to all of its other problems, the Weimar Republic lacked such a framework. Within constitutional theory there was, for example, a marked emphasis upon the notion of the state, conceived as the locus of a unified political will standing (both morally and politically) above society, economy and even the Constitution. There was nothing inherently malign about this understanding, but it exhibited features which could be exploited by those of malign intent. This possibility came to fruition within the shadow of Max Weber. For Weber's thought included strong elements of subjectivism. Carl Schmitt was to show how subjectivism, particularly when combined with the idea of the state as embodying a unified political will, could subvert liberal democracy.

In a world of pure subjectivity, without moral reason, there can be no rationally grounded common good, but only the clash of individual desires. In the absence of reasoned conclusions upon which diverse reflective subjects can converge, unity can be attained only by subjective uniformity. In such a context, a unified political will requires a high degree of homogeneity in the populace. At the same time, an unqualified subjectivism denies the possibility of moral error, and consequently erodes the tolerance which might oppose enforced homogeneity. For tolerance depends in part upon the acknowledgement that prevailing ideas might be mistaken. Far from underpinning tolerance (as people sometimes naively imagine) moral subjectivism places tolerance on a par with intolerance: each is seen as an ungrounded choice. Furthermore, a culture that emphasises subjectivity tends to equate the importance of a moral value with the intensity with which it is asserted. The strategic value thereby attached to uncompromising stridency risks turning liberal society into what Leo Strauss called “a seminary of intolerance”.

One does not escape moral subjectivism simply by seeing its potential corrosiveness and wishing it away. What is needed is a measured assessment of the part that reason can still play in our law and in our lives. Alexy seeks to provide precisely such an assessment, and it is here that the real importance of his work lies.

Before the publication of the present book, Alexy's contribution was principally associated with three books, all published in English translations by Oxford University Press: A Theory of Legal Argumentation (Oxford 1989); A Theory of Constitutional Rights (Oxford 2002); and The Argument from Injustice (Oxford 2002). These books explored discrete topics, but nevertheless embodied a unified theoretical viewpoint which was further developed in a very large number of essays scattered across a variety of journals in both German and English. That viewpoint now finds its mature and systematic expression.

Alexy's first book suggested that the rationality of legal argumentation is best revealed by a turn from argument understood as a semantic relation between norms and propositions to argument as a process or activity: argument as discourse. This was not at all to suggest a sociological or psychological approach, but an acknowledgement of the deep normative constraints, implicit within discourse, that structure the exchange of arguments. Discourse theory (as developed by Habermas, Apel and Alexy) is, fundamentally, a way of answering the suggestion that all reasoned arguments must ultimately rest upon dogmatism (in the form of supposedly self-evident or indubitable certainties), or upon circularity, or upon an infinite regress of justifications. The response to this trilemma views statements as justifiable by reference to a rule-governed procedure of discussion. Since the upshots of reasoned discussion will depend to some extent upon the intellectual starting points of the discussants, an open and appropriately regulated discussion will commonly lead to a diversity of rational possibilities, while also ruling out a host of discursive impossibilities. For the purposes of social cooperation, the relative indeterminacy of reason must therefore be overcome by the institution of law. At the same time, the interpretation and application of law must itself be informed by rational discourse. On this account, therefore, the relationship between positive law and rational discourse in some respects resembles more traditional understandings of the relationship between positive law and natural law, wherein positive law lends determinacy to the requirements of natural law, while natural law lends determinacy to our interpretations of positive law. Discourse theory is intended to be sustainable within the outlook of those who, like Alexy, believe that traditional natural law theory rests upon what he calls “unsustainable presuppositions”.

The study of legal argumentation was followed by a rich and carefully developed analysis of constitutional rights, treating rights (in line with proportionality doctrine) as “optimisation requirements” to be balanced against other considerations. This book, A Theory of Constitutional Rights, is certainly Alexy's most widely read and influential contribution. But, although he presents it as a study of German law, it has a much wider philosophical significance. Furthermore, the argument of the book sits tightly and systematically with the broader jurisprudential views that Alexy has developed and refined across the entirety of his career. Those broader jurisprudential views shaped his third book, The Argument from Injustice, which is a robust and insightful defence of Gustav Radbruch's insistence that extremely unjust enactments should not be treated as law (the so-called “Radbruch formula”).

In more recent years, Alexy's very numerous papers in learned journals have been developing some new aspects to his thought. These evolved naturally from Alexy's earlier work, and serve to strengthen the links with the outlook of Radbruch. The earlier work presented law's role as that of giving determinacy to the requirements of reason; and, on that basis, it was suggested that law necessarily makes a “claim to correctness”. Alexy now deepens that idea by suggesting that law has a “dual” nature: it possesses both a real dimension (involving its character as posited and effective) and an ideal dimension (involving a claim to serve justice). Without this dual nature, law could not fulfil its role. Moreover, the dual nature of law is explicitly or implicitly present “in all fundamental questions of law”. For that reason, it is “the single most essential feature of law, and it shows why legal positivism is an inadequate theory of the nature of law” (p. 50).

Contemporary legal positivists have expressed puzzlement in relation to Alexy's theory. Some have doubted whether law is the sort of thing that makes claims at all. Others (such as Raz) have themselves ascribed claims to law by placing those claims in the mouths of law's officials. They suggest that nothing incompatible with positivism follows from law's claims. For, they point out, law can claim to be just without actually being just. Consequently, the injustice of the law can provide no reason for denying its status as law, even if a claim to serve justice is inherent in law's nature. Indeed, it has been suggested that law's claim to serve justice reinforces legal positivism rather than offering a refutation of that position. Raz has himself argued that law, through its officials, claims to be morally binding. But, in Raz's view, the law does not in fact possess the morally binding force that it claims.

In reflecting upon this argument, consider the type of grossly unjust regime that might fall foul of the Radbruch formula. Is it really plausible to suggest that such a regime claims to serve justice, even though its enactments evince a casual disregard for justice's most basic requirements? Since a claim to serve justice must pragmatically imply at least an intention to be just, and some concern for justice, it can scarcely be combined with an evident willingness to disregard even the most basic considerations of justice. Gross departures from justice therefore call into question the system's claim to serve justice. And, if that claim is an integral part of law's nature, the departure must detract from the legality of the system as well as from its justice.

The positivist response to Alexy's argument seems to assume that claims to justice (or moral bindingness) can be ascribed to law on the basis of relatively discrete features of legal practice. Raz, for example, seems at times to be suggesting that a claim to moral bindingness is unavoidably present within the language of rights and duties used by law's officials. This analogises the situation to one where, in my otherwise completely normal life, I repeatedly claim (in conversation, emails and letters) that I am Napoleon. On such an approach, even the most iniquitous system might still make a claim to justice or moral bindingness, just as Mr. Humdrum might claim to be Napoleon in spite of his modest and unassuming lifestyle, and his temporal location 200 years after Napoleon's death.

However, when treated as detachable in this way from the wider context, the discrete features invoked (i.e. the language of rights and duties, in our example) appear to be deeply opaque or ambiguous. What exactly does Humdrum mean by saying that he is Napoleon? Since his claim sits so oddly with his circumstances, we hesitate to treat it as bearing its meaning upon its face. What exactly do the judges mean when they speak of rights and duties? Even if legal rights and duties may generally be viewed as a species of moral right or duty (as Raz claims), this may not be true within a legal system that has manifestly abandoned the pursuit of justice. Might not the obvious injustice of the law drain the vocabulary of its normal moral resonance, converting it into a purely technical language that applies the rules without any claim to justice or moral bindingness?

If these interpretative issues could somehow be overcome, a further problem would remain. For, if “claims” can be ascribed to law on the basis of relatively narrow features, independently of the wider context within which those features exist, it is unlikely that any such claims could be regarded as integral to law's nature. When depicted as depending exclusively upon relatively discrete features abstracted from a wider context, the claims of law come to seem superficial and contingent. Perhaps (as Christoph Kletzer has pointed out) any system of norms (such as the rules of a tennis club) could make the relevant claims, without this affecting the system's nature in other respects. And, as Finnis has pointed out, a system resembling law in all other respects might choose to make no such claims. Consequently, it could be difficult to treat such claims as essential features of law's nature.

Law does not make claims. But the practices making up a legal order nevertheless express an idea: the idea of law. Those practices are oriented towards the idea of law in much the same way that the relationship of friendship is oriented towards the idea of friendship. Those who are friends value their friendship, and guide their conduct by respect for that value. When they no longer honour the value of friendship, they are no longer friends. Similarly, a system of governance that entirely abandons its concern with justice ceases to be a system of law. For legal thought must be guided by the idea of law, and that is an idea that is intimately bound to justice. In this imperfect world, the demands of legality and of justice may sometimes conflict. But, nevertheless, each is fully attainable only in conjunction with the other. Substantial departures from justice (falling outside the range of good faith moral disagreement but not amounting to a wholesale abandonment of justice as an aspiration) can seriously detract from legality. In such contexts, to honour the value of law, one must sometimes apply the Radbruch formula.