1. Introduction
Legal philosophy is generally divided into two philosophical domains: normative jurisprudence and analytical jurisprudence. Normative jurisprudence aims at a rational evaluation and criticism of existing laws and legal institutions. While one can practice normative jurisprudence by appealing to economic or other non-moral standards, the evaluative criteria normative jurisprudence employs are first and foremost moral criteria specifying what law ought to be (Murphy and Coleman Reference Murphy and Coleman1990: 1). In contrast to normative jurisprudence, analytical jurisprudence does not seek a normative analysis of law. Analytical jurisprudence is theoretically explanatory and descriptive (Kramer Reference Kramer2012: 126). It accounts for what law is rather than what law ought to be.
Central to analytical jurisprudence is the question of whether and, if so, how law is related to morality. In response to this question, legal positivists defend what is usually called ‘the separability thesis’, which states that there is no necessary connection between morality and law (Coleman and Leiter Reference Coleman, Leiter and Patterson2010: 228). More narrowly, the separability thesis maintains that norms need not accord with the requirements of morality to be properly regarded as laws or legally valid.Footnote 1 On the other hand, natural law theorists believe that the nature of law cannot be explained without appealing to moral principles.Footnote 2 They argue, in John Finnis’ words, that ‘… an understanding of law presupposes a practical understanding (i.e. an understanding of the point, the good) of community, justice and rights, and authority−as reasons for choice and action’ (Finnis Reference Finnis1986: 492).Footnote 3 The divide between the traditions of legal positivism and natural law theory is the dominant framework in addressing the question of the relation between morality and law in analytical jurisprudence.Footnote 4
Kant develops a series of moral principles that he thinks we should employ to evaluate and rationally criticize existing laws. According to Kant, these moral principles determine to which extent a regime is morally legitimate. The most important principle among them is the Universal Principle of Right. According to the Universal Principle of Right, an action that is not compatible with the external freedom of others is wrong and laws that permit or require such an action are morally illegitimate. The Universal Principle of Right is closely connected to Kant’s idea of ‘innate right to freedom’, which Kant defines as ‘independence from being constrained by another’s choice’ (MM, 6: 237).Footnote 5 All this means that Kant defends a relatively clear position in normative jurisprudence. The Universal Principle of Right and the innate right to freedom, among others, are normative sources to criticize existing laws. Kant defends a broadly liberal political morality that incorporates crucial republican elements.
The amount of research concerning Kant’s position within analytical jurisprudence and his potential contribution to that major jurisprudential area fall far behind the amount of research dedicated to Kant’s position in normative jurisprudence. This paper is an attempt to remedy this shortcoming in the current literature. The main issue in this paper is to which extent Kant’s views about the relation between morality and law should be considered as an instance of natural law theory or legal positivism. Robert Alexy is one of the few philosophers who addressed this issue in some of his works. My strategy is to evaluate Alexy’s interpretation of Kant, which he developed in Alexy (Reference Alexy2019) published in this journal. Alexy believes that Kant defends a version of natural law theory that puts moral limits on legal validity. More specifically, according to Alexy, Kant endorses the thesis that, if a norm is radically unjust, it cannot be regarded as a law even if it is enacted and executed by actual legal authorities. I show that Kant does not adopt this thesis. I argue that Kant defends the positivist separability thesis that rules need not meet moral requirements to be properly regarded as legal norms.
I proceed as follows. In Section 2, I critically discuss Alexy’s tripartite classification of different types of natural law theory. Since Alexy’s interpretation of Kant’s legal philosophy is based on this classification, we first need to discuss it. In Sections 3, 4, 5, and 6, I analyse Alexy’s argument for his interpretation that Kant puts moral limits on the conditions under which a rule can be a legal norm. Alexy’s interpretation draws on three cases Kant addresses in his different works on moral and legal philosophy. They concern what Kant calls ‘inner morality’, anti-enlightenment contracts, and contracts of slavery. I show that Alexy’s analysis of these three cases does not suffice to justify his interpretation. In Section 7, I consider how my interpretation of Kant’s legal philosophy sheds light on its connections with the positivist theories of Hans Kelsen and H. L. A. Hart. In Section 8, I critically comment on Alexandre Trivisonno’s interpretation of Kant.
2. Three types of natural law theory
2.1 Exclusive non-positivism
The first type of natural law theory in Alexy’s classification is ‘exclusive non-positivism’. This type of natural law theory endorses the motto ‘lex iniusta non est lex’, or in its English translation ‘an unjust law is no law’. According to exclusive non-positivism, moral merit is a necessary condition of legal validity and, hence, the positivist separability thesis must be rejected. This form of natural law theory excludes all moral defects from the consideration of legal validity and embraces the idea that ‘… every moral defect, every injustice yields legal invalidity’ (Alexy Reference Alexy2012a: 5).Footnote 6
Alexy thinks that Kant does not adopt exclusive non-positivism. He points out that this type of natural law theory has a crucial shortcoming, which can be explicated if we consider an objection Jeremy Bentham raises against William Blackstone’s version of exclusive non-positivism. According to Blackstone, if a social norm is incompatible with the natural law, which he thinks is the source of morality, that norm cannot be a law (Blackstone Reference Blackstone and Stern2016: 35). Bentham finds Blackstone’s view ‘dangerous’ (Bentham Reference Bentham and Harrison1988: 95). Benthams’s reason for this is that Blackstone’s view has the tendency ‘… to impel a man, by the force of conscience, to rise up in arms against any law whatever that he happens not to like’ (Bentham Reference Bentham and Harrison1988: 94–5). To put this objection in Hart’s words, if Blackstone is right, we face ‘the danger that law and its authority may be dissolved in man’s conception of what law ought to be …’ (Hart Reference Hart1958: 598).
Bentham’s view may appear rather crude, but it is based on a sound premise about moral disagreement. To see this, consider Alexy’s analysis of what he calls ‘the problem of practical knowledge’. The problem of practical knowledge refers to the fact that even fully conscientious individuals who seek to solve social problems solely on moral grounds may disagree about what morality requires. As Alexy puts it, ‘there are a great many practical questions in which no agreement can be arrived at, not even between reasonable persons’ (Alexy Reference Alexy, George and George2017: 322). Even if we appeal to the same moral values or principles, our conclusions may differ. Hence, disagreement among conscientious individuals over the best solution to at least complex moral problems about justice seems unavoidable.
The fact that moral disagreement is a fact of our social lives shows that exclusive non-positivism is problematic. Exclusive non-positivism regards harmony with morality as a necessary condition of legal validity. This means that, if exclusive non-positivism is correct, a social norm that is a valid legal rule according to a person may be rejected by another individual as legally invalid since they might conscientiously disagree about whether that norm satisfies the moral principles they take to be among the necessary conditions of legal validity. This further implies that, if exclusive non-positivism is generally endorsed by the members of a community and they disagree about the moral status of an official rule, social incoordination problems might ensue. Alexy captures this point when he states that ‘[e]xclusive non-positivism gives too little weight to the factual or real dimension of law. Owing to the controversial nature of many moral issues, it would amount to anarchism’ (Alexy Reference Alexy2012a: 5). I believe that Alexy’s objection against exclusive non-positivism based on the existence of conscientious moral disagreement is cogent. I also believe, however, that a similar objection should be raised against the type of natural law theory Alexy himself endorses and attributes to Kant. I now turn to that type of natural law theory.
2.2 Inclusive non-positivism
The second type of natural law theory in Alexy’s classification is ‘inclusive non-positivism’. Inclusive non-positivism is the view that ‘… moral defects undermine legal validity if and only if the threshold of extreme injustice is transgressed. Injustice below this threshold is included in the concept of law as defective but valid law’ (Alexy Reference Alexy2010: 177, emphasis added). Alexy defends inclusive non-positivism. According to this type of natural law theory, moral defects in law admit degrees and the existence of moral defects leads only to legal defectiveness insofar as they do not reach the degree of extreme or unbearable injustice, but once that degree is reached, legal validity is lost.Footnote 7 Inclusive non-positivism is expressed by the Radbruch formula that ‘extreme injustice is no law’ (Alexy Reference Alexy2002: 40–62; see also Alexy Reference Alexy and Dyzenhaus1999, Radbruch Reference Radbruch2006: 7).
Alexy argues that Kant adopts inclusive non-positivism. I shall argue below that Alexy’s interpretation of Kant as an inclusive non-positivist is wrong. I only would like to point out now that inclusive non-positivism is a problematic view, even on Alexy’s own criteria. Recall Alexy’s challenge against exclusive non-positivism drawing on the problem of practical knowledge. Alexy argues that exclusive non-positivism is problematic because even fully conscientious people disagree about what morality requires. Given the existence of conscientious moral disagreement among individuals, if we put moral limits on what law is, as exclusive non-positivism does, which norms are legally valid depends upon which moral principles one happens to adopt. The problem with inclusive non-positivism is that conscientious disagreement can also arise when different individuals make judgements as to whether the degree of extreme injustice is reached in a particular case.
Consider Alexy’s own version of inclusive non-positivism. Alexy defines extreme injustice in terms of cases in which human rights are violated and argues that legal validity is lost in these cases.Footnote 8 The weakness of this view is that people often disagree about what human rights require in particular situations even in cases in which we try our best to remain conscientious. This is confirmed by Alexy’s own characterization of the essential features of human rights. Among the properties of human rights, Alexy includes abstractness (Alexy Reference Alexy2021: 150–2). Alexy thinks that the abstractness of human rights implies that there is a gap between the principles expressing human rights and their application in concrete cases. He states, for instance, that ‘[i]t is easy to agree that all have a right to good health, but on the question of what that means in a concrete case, protracted controversy is possible’ (Alexy Reference Alexy2021: 144, emphasis added). Therefore, if the existence of conscientious disagreement is a reason to reject exclusive non-positivism, it is equally a reason to reject inclusive non-positivism.
2.3 Super-inclusive non-positivism
The third type of natural law theory about the relation between law and morality in Alexy’s classification is ‘super-inclusive non-positivism’. In contrast to exclusive and inclusive non-positivism, super-inclusive non-positivism holds that moral defects never undermine legal validity. This version of natural law theory ‘… includes all authoritatively issued and socially efficacious norms in spite of their moral defects in the class of legally valid norms’ (Alexy Reference Alexy, George and George2017: 328). In other words, super-inclusive non-positivism does not include compliance with morality among the conditions of legal validity.
One might question whether super-inclusive non-positivism is really an instance of natural law theory at all since it does not seem to be committed to any necessary connection between law and morality. Alexy thinks that super-inclusive non-positivism is a type of natural law theory because it endorses what he calls a ‘qualifying connection’ between law and morality. A qualifying connection between law and morality refers to the idea that a moral defect in a legal rule is also necessarily a legal defect (Alexy Reference Alexy and Dyzenhaus1999: 24). What distinguishes super-inclusive non-positivism from legal positivism is its commitment to this necessary connection between moral defectiveness and legal defectiveness.Footnote 9
Alexy believes that super-inclusive non-positivism suffers from the opposite shortcoming exclusive legal positivism has. According to Alexy, exclusive non-positivism is unreasonably biased in favour of what he calls ‘the ideal dimension of law’ and does not give sufficient importance to ‘the real dimension of law’. Alexy’s idea is that exclusive non-positivism simply overlooks the fact that there are immoral social norms that are enacted and enforced by real human institutions. And he argues that super-inclusive non-positivism is unreasonably biased against the ideal dimension of law since it allows that even radically unjust norms can be legally valid (Alexy Reference Alexy2008: 290). A proper evaluation of Alexy’s criticism of super-inclusive non-positivism would go far beyond the boundaries of this paper. I shall only stress that super-inclusive non-positivism avoids the problem I laid out above that exclusive and inclusive non-positivism suffer from.
We saw that the existence of conscientious disagreement about morality undermines both exclusive and inclusive non-positivism. These versions of natural law theory lead to situations in which what law requires in a particular case cannot be settled even by reasonable individuals and this is incompatible with the univocality of law. We should add to this that exclusive non-positivism is also problematic due to its account of the effects of moral defects on legal validity. Exclusive non-positivism states that all moral defects in social norms undermine their legal validity. This is incompatible with the fact that there are clear cases of law that are morally defective. What is more, if we assume, as exclusive non-positivism does, that every moral defect undermines legal validity, then we must reject as legally invalid almost all laws we normally regard valid since most laws have at least minimal moral defects. Obviously, it is very hard to find a legal rule that is morally perfect in all relevant respects. These problems that exclusive and inclusive non-positivism face arise from their commitment to the idea that there are moral requirements for legal validity. Without making such a commitment, super-inclusive non-positivism faces none of them.
3. Alexy’s interpretation of Kant’s natural law theory
Alexy (Reference Alexy2008) argues that Kant should be considered as a natural law theorist who thinks that ‘… legal validity is no way at all affected by moral defects or moral incorrectness’ (p. 288). According to this reading, Kant thinks that immorality in law means only that it is legally defective, not that it is legally invalid. In 2008, Alexy thought, in other words, that Kant defends super-inclusive non-positivism. Alexy argued in 2010 as well that ‘[a] version of super-inclusive non-positivism … is to be found in Kant’s combination of the postulate of “unconditional submission” under positive law with the idea of a necessary subjugation of positive law to non-positive law’ (Alexy Reference Alexy2010: 176).Footnote 10 However, later Alexy (Reference Alexy2019) revised his interpretation. He did not change his view that Kant is a natural law theorist, but he dropped his reading of Kant as a super-inclusive non-positivist. I will now focus on Alexy’s later reading.
Alexy thinks that injustice is a degreed notion. According to him, there are cases of mild as well as extreme injustice. As we saw above, the form of natural law theory Alexy himself defends adopts the idea that legal validity is lost when a rule is extremely unjust. In Alexy’s reading of Kant’s legal philosophy in 2019, Kant agrees that justice is a condition of legal validity. That being said, Alexy argues that Kant’s view on this issue differs from his own in a significant respect. According to Alexy, Kant believes that only very extreme injustice is no law (Alexy Reference Alexy2019: 505). Alexy’s reading draws on three cases Kant addresses in his different works on moral and legal philosophy. The first concerns Kant’s notion of ‘inner morality’. The second and third cases focus on what Kant calls ‘null and void’ contracts. Alexy’s analysis of these issues aims to show that Kant puts moral limits on legal validity. I argue that Alexy fails to establish this thesis.
4. ‘Inner morality’ and legal validity
In the Appendix to the second edition of the Doctrine of Right, Kant states the following imperative: ‘Obey the authority who has power over you (in whatever does not conflict with inner morality [in allem, was nicht dem inneren Moralischen wiederstreitet])’ (MM, 6: 371). This imperative lies at the basis of Alexy’s ‘exemption-clause argument’ (Alexy Reference Alexy2019: 504). According to this argument, in stating this imperative, Kant endorses Radbruch’s view that law has an outermost moral border and maintains that norms that conflict with inner morality cannot be legally valid (pp. 504–5). Alexy states:
One can assume that Kant’s ‘conflict with inner morality’ is a stronger threshold than Radbruch’s ‘intolerability’. The structure, however, is the same. This makes it possible to capture the similarities as well as the differences with an outermost border formula attributed to Kant that runs as follows: Very extreme injustice is no law. (Alexy Reference Alexy2019: 505)
I believe that this imperative cannot be considered as evidence of Kant’s alleged inclusive non-positivism since it is not about legal validity at all. It is rather about the conditions under which our duty to obey existing law is undermined by immorality. In citing this imperative as implying a certain view about the relation between legal validity and morality, Alexy confuses the question of legal validity with that of the obligation to obey laws. It is perfectly consistent to think that, even though a social norm is legally valid, one ought not to obey it. This point is clearly developed by Hart, who thinks, as a legal positivist, that immorality in a law is compatible with that law’s being legally valid. Hart states:
[we] should preserve the sense that the certification of something as legally valid is not conclusive of the question of obedience, and that, however great the aura of majesty or authority which the official system may have, its demands must in the end be submitted to moral scrutiny. (Hart Reference Hart1994: 210)
What we can infer from Kant’s imperative is that we are obliged to obey a law only if it is in accordance with inner morality, not that laws that conflict with inner morality are actually not laws.
Kant refers to the notion of inner morality in the Religion within the Boundaries of Mere Reason as well.Footnote 11 In a passage in Book III of the Religion, Kant makes a distinction between an ‘ethical community’ and a ‘juridical community’ (R, 6: 98).Footnote 12 With respect to the juridical community, Kant makes three crucial claims. First, the laws of a juridical community are given by ‘the mass of people joining in a union’ (ibid.). Second, Kant states what he calls the ‘principle of all external right’, which is almost identical to the Universal Principle of Right (ibid.).Footnote 13 Third, and more important for my purposes here, the laws of a juridical community concerns only overt behaviour (6: 99). Here, Kant connects his distinction between a juridical and an ethical community to his notion of inner morality. He argues:
… [the rules in an ethical community] are exclusively designed to promote the morality of actions (which is something internal, and hence cannot be subject to public human laws) whereas these public laws (and in this they constitute a juridical community) are on the contrary directed to the legality of actions, which is visible to the eye, and not to (inner) morality which alone is at issue here. (R, 6: 99)
The key point in this passage is that, according to Kant, inner morality is not a matter of juridical laws but only ethical norms. Kant’s point that inner morality concerns solely ethical issues supports my interpretation that, in the above imperative in the second edition of the Metaphysics of Morals, Kant does not put forward a view about legal validity since, as a moral notion that concerns only inner ethical conduct, the notion of inner morality cannot ground a claim about legal validity.
Moreover, believing that it is not exactly clear what Kant means by inner morality in the Appendix to the second edition of the Metaphysics of Morals, Alexy draws on a note from Kant’s Reflexionen zur Rechtsphilosophie (Alexy Reference Alexy2019: 504). That note says:
Force, which does not presuppose a judgment having the validity of law [vor welche kein rechtskräftig Urteil vorher geht] is against the law [unrechtmäßig], consequently [the people] cannot rebel except in the cases which cannot at all come forward in a civil union, e.g., the enforcement of religion, compulsion to unnatural sins [unnatürlichen Sünden], assassination, etc., etc. (Refl 8051, 19: 594)
Like the imperative in the Appendix to the second edition of the Metaphysics of Morals, this passage is about the conditions under which it is morally permissible to disobey laws and legal authorities. If political force is employed for purposes like religious coercion, coercion to unnatural sins, and assassination, one is morally allowed to disobey. The fact that one has no moral obligation to obey a law that promotes these purposes does not necessarily entail that it is not legally valid or no law at all. Hence, contrary to Alexy’s intentions, this note does not show that Kant’s notion of legal validity involves moral requirements. One may believe that one has no moral obligation to obey an unjust law or one can alternatively resist that law. In both cases, the legal validity of the legal rule in question is not necessarily affected.
5. Enlightenment and ‘null and void’ contracts
The second case Alexy considers is in a passage in ‘What is Enlightenment?’. That passage begins with the following question:
[S]hould not a society of clergymen … be authorized to bind itself by oath to a certain unalterable creed, in order to carry on an unceasing guardianship over each of its members and by means of them over the people, and even to perpetuate this? (WIE, 8: 38)
Kant argues that such a contract is impossible. He states:
such a contract, concluded to keep all further enlightenment away from the human race forever, is absolutely null and void [null und nichting], even if it were ratified by the supreme power, by imperial diets and by the most solemn peace treatises. (WIE, 8: 39)
Alexy uses this passage to argue that, according to Kant, a contract that precludes enlightenment is legally invalid even though it is concluded in accordance with existing legal and institutional procedures (Alexy Reference Alexy2019: 507–8).
There are three points to be considered about ‘What is Enlightenment?’ to evaluate Alexy’s interpretation of it. First, this passage fails to support Alexy’s interpretation. Second, Kant’s distinction between public and private uses of reason in ‘What is Enlightenment?’ shows that he endorses the separability thesis. Third, in ‘What is Enlightenment?’, Kant also endorses the more radical positivist thesis that it is a good thing about laws that their legal validity does not necessarily depend on whether they accord with morality. I shall now discuss these issues. After this discussion, I will move onto the third case Alexy draws upon in his interpretation of Kant as an inclusive non-positivist.
5.1 Illegitimacy of anti-enlightenment contracts
First, how should we interpret Kant’s claim in ‘What is Enlightenment?’ that contracts that preclude humanity from achieving enlightenment are ‘null and void’? I suggest that here Kant is concerned not with legal invalidity but only with moral illegitimacy. In other words, the most plausible way to make sense of Kant’s claim is to think that, according to Kant, these contracts are null and void not in a legal sense but only in the moral sense that they are morally illegitimate and hence ought not to be made. The rest of the passage in which the ‘null and void’ accusation appears favours this interpretation. In the rest of that passage, Kant focuses solely on overtly prescriptive issues about moral authorization and moral permissibility rather than descriptive issues connected to legal validity. For instance, Kant claims that, if a contract makes enlightenment impossible, succeeding generations are ‘… perfectly authorized to reject such decisions as unauthorized and made sacrilegiously’ (WIE, 8: 39, emphases added). He also argues in the same passage thus:
… it is absolutely impermissible to agree, even for a single lifetime, to a permanent religious constitution not to be doubted publicly by anyone and thereby, as it were, to nullify a period of time in the progress of humanity toward improvement and make it fruitless and hence detrimental to posterity. (WIE, 8: 39, emphasis added)
Therefore, what Kant has in mind when he says that anti-enlightenment contracts are null and void is that we are morally authorized to reject them as illegitimate since it is morally impermissible to agree to them, not that they are legally invalid.
This interpretation is further supported if we consider the general principle that lies at the basis of Kant’s claim that contracts making enlightenment impossible are null and void. Kant states that principle in the same passage. It says that ‘what a people may never decide upon for itself, a monarch may still less decide upon for a people’ (WIE, 8: 40). Kant’s idea is that, since a people can never decide for itself that it can never achieve enlightenment, this principle entails that a ruler cannot impose such a decision on it. Kant elaborates on this principle in some of his other works on moral and legal philosophy.
In ‘On the Common Saying: That May Be True in Theory, but It Is of No Use in Practice’, Kant refers to this principle as ‘the universal principle by which a people has to appraise its rights’ and emphasizes its two crucial features (TP, 8: 304).Footnote 14 First, it can only be used negatively (ibid.). Kant’s idea is that one can appeal to this principle to find out not what is to be legislated but what is not to be legislated.
The second feature of this principle is much more important for my interpretation. This principle can be appealed to solely in cases in which existing laws are silent on an issue. Hence, if there is no existing law demanding that a certain religious dogma be respected without change and revision, we may assume that it is not a legal requirement to stick to a religious dogma to be preserved without revision. Kant adds that ‘in all cases, however, where something of this sort was nevertheless arranged by the supreme legislation, general and public judgments could be passed on it, but resistance to it in word or deed could never be summoned’ (TP, 8: 305). Kant’s view is that citizens must enjoy a spirit of freedom by making public use of reason to share their opinions about existing state policies, especially if they impede enlightenment, but if these policies are officially adopted as laws, their status as an impediment to enlightenment does not alter the fact that they ought to be obeyed and, hence, are legally valid.
5.2 Public and private uses of reason in ‘What is Enlightenment?’ and legal positivism
Moving onto the second issue to be considered in ‘What is Enlightenment?’, the textual evidence in this text for my interpretation that, according to Kant, legal validity is not necessarily a matter of morality extends far beyond what Kant says about anti-enlightenment contracts. My interpretation appears even more convincing if we consider Kant’s distinction between public and private uses of reason, which lies at the heart of ‘What is Enlightenment?’.
Kant thinks that enlightenment is achieved only if we are free to make public use of reason (WIE, 8: 37). He argues that individuals must be allowed to make full use of their freedom to express their opinions and to share them with the public if enlightenment is to be a real possibility.Footnote 15 Kant states, on the other hand, that the private use of reason ‘… is that which one can make of it in a certain civil post or office with which he is entrusted’ (ibid.). Kant’s idea here is that, when an individual occupies an official position within an institution, she can use her reason only under certain externally imposed official limits on the basis of which that institution functions. One of Kant’s examples is a clergyman who is hired by a religious institution to deliver a class on a religious topic. According to Kant, the clergyman is bound to deliver the class ‘… in accordance with the creed of the church he serves, for he was employed by it on that condition’ (8: 38). In his official position, the clergyman is in a passive position and can only make use of his private reason by performing his official duties.
The fact that the private use of reason always depends upon a set of official practices and principles that are not open to questioning is of pivotal importance to understanding Kant’s legal positivism in ‘What is Enlightenment?’ The message Kant wants to convey in his discussion of the distinction between the private and public uses of reason is that, while we have full freedom to publicly criticize the official requirements we are subject to, we cannot but obey them. This general point also applies to each citizen in relation to legal authorities. Kant states the following about our legal duty to pay taxes and our right to publicly criticize them:
A citizen cannot refuse to pay the taxes imposed upon him; an impertinent censure of such levies when he is to pay them may even be punished as a scandal (which could occasion general insubordination). But the same citizen does not act against the duty of a citizen when, as a scholar, he publicly expresses his thoughts about the inappropriateness or even injustice of such decrees. (WIE, 8: 37)
What Kant says in this passage can be perfectly formulated in terms of the positivist distinction between what law is and what law ought to be. In making public use of reason, we may criticize existing legal rules by making judgements about how they ought to be, but the fact that we find them morally deficient does not entail that they are not really laws and that we are free to disobey them. Like a clergyman who is expected to teach the dogmas of a religion, citizens are passive when it comes to their obedience to legal rules. Citizens are passive in the sense that, whatever their moral assessment of them, they cannot but recognize the validity of the legal rules they are subject to and obey them. This entails the positivist separability thesis that moral merit is not a necessary condition of legal validity.
5.3 Kant’s normative legal positivism in ‘What is enlightenment?’
The third issue to consider in ‘What is Enlightenment?’ concerns Kant’s endorsement of normative legal positivism, i.e. the view that it is a good thing about laws that their legal validity does not necessarily depend on their moral status. In his article ‘Kant’s Legal Positivism’, Jeremy Waldron argues that Kant defends normative legal positivism (Waldron Reference Waldron1996: 1540). In his reading of Kant, Waldron does not consider ‘What is Enlightenment?’, but I believe that there are points there that support Waldron’s reading.
To see Kant’s normative legal positivism in ‘What is Enlightenment? we need to look at the passage at the beginning of which Kant says that for enlightenment ‘… nothing is required but freedom’ (WIE, 8: 36). In this passage, Kant also acknowledges the obvious fact that ‘there are restrictions on freedom’ and asks, rather surprisingly, ‘… what sort of restriction hinders enlightenment, and what sort does not hinder but instead promotes it?’ (WIE, 8: 37, emphasis added). The surprising aspect of this question is its second part. In asking which sort of restriction on freedom promotes enlightenment, Kant assumes that some restrictions on the freedom of thought and expression promote enlightenment and, hence, are good. He states:
I reply: The public use of one’s reason must always be free, and it alone can bring about enlightenment among human beings; the private use of one’s reason may, however, often be very narrowly restricted without this particularly hindering the progress of enlightenment. (WIE, 8: 37)
Here, Kant first responds to the first part of the question by claiming that restrictions on the public use of reason hinder enlightenment. Then, he replies to its second part by saying that restrictions on private reason need not hinder enlightenment. Recall, however, that the second part of the question asks which restriction on freedom does not hinder but rather promotes enlightenment. Hence, Kant thinks that some restrictions on private reason promote enlightenment, and we already know that the kind of restriction on private reason Kant has in mind concerns judgements about the appropriateness of the legal rules we are subject to in our official relation to them. It turns out, therefore, that, according to Kant, that we do not make moral judgements in our official positions about the moral appropriateness of official rules, simply accepting them as legally valid and obeying them, is a good thing and promotes enlightenment.
6. Kant on slavery contracts
The third case Alexy draws upon in his interpretation of Kant is about yet another type of contract, i.e. contracts of slavery. Kant states in the Metaphysics of Morals:
… a contract by which one party would completely renounce its freedom for the other’s advantage would be self-contradictory, that is null and void [null und nichtig], since by it one party would cease to be a person and so would have no duty to keep the contract but would recognize only force. (MM, 6: 283, emphasis added)
According to Alexy, this passage lends a compelling reason to think that Kant puts moral constrains on legal validity (Alexy Reference Alexy2019: 507). He thinks that, in this passage, Kant argues that contracts of slavery are legally invalid or ‘null und nichtig’ because slavery is an immoral practice. In other words, in Alexy’s reading, Kant thinks that the reason why contracts of slavery are legally invalid is a moral reason, i.e. their immorality.
If Kant does think that the nullity of contracts of slavery arises from moral reasons, Alexy is correct that Kant puts moral conditions on legal validity. Although Alexy does not consider it, it appears that one can find such a moral reason for the legal invalidity of contracts of slavery in the formula of universal law (FUL) of the Categorical Imperative, which states: ‘act only in accordance with that maxim through which you can at the same time will that it become a universal law’ (G, 4: 421). FUL is applied in two steps. First, it demands that our maxims be universalizable without any contradiction in conception. There are maxims that cannot be consistently conceived as universal laws. In Kant’s words, ‘some actions are so constituted that their maxim cannot even be thought without contradiction as a universal law of nature’ (G, 4: 424). The second step involves a contradiction in the will. Some maxims can be thought of as universal laws but cannot be consistently willed as universal laws. These maxims suffer not from conceptual contradictions when universalized but from a contradiction the will has with itself (G, 4: 424).
Since Kant thinks that FUL shows that actions are immoral because they involve a contradiction and he says in the passage quoted at the beginning of this section from the Metaphysics of Morals that slavery contracts are self-contradictory, one can conclude that, according to Kant, the Categorical Imperative identifies such contracts as immoral and, hence, they are null and void due to moral reasons. For all the appearances, however, this reading is mistaken. I suggest that, in the passage in the Metaphysics of Morals in which Kant argues that contracts of slavery are null and void, he argues that such contracts are null and void not because of moral reasons but because of their sheer impossibility. Contracts of slavery are impossible since they are conceptually incoherent. The form of conceptual incoherence that contracts of slavery involve is distinct from the inconsistencies that immoral maxims lead to when they are universalized, and understanding this type of conceptual incoherence enables us to see that what lies at the basis of Kant’s claim that such contracts are null and void is not a moral consideration. To clarify my interpretation of Kant’s characterization of contracts of slavery as simply conceptually incoherent and how this type of incoherence is distinct from the inconsistencies in morally unworthy maxims, I shall appeal to O’Neill’s insightful account of Kant’s universalizability test in her ‘Consistency in Action’.
O’Neill notes that FUL demands from autonomous agents ‘… to impose a certain consistency on their actions if they are to avoid what is morally unacceptable’ (O’Neill Reference O’Neill1990: 81–2). O’Neill’s idea is that actions performed on non-universalizable maxims suffer from a particular type of incoherence. I noted the two forms of incoherence of morally unworthy maxims have. However, O’Neill notes that not all types of incoherence arise from attempts at universalization. In other words, there are ways in which our actions express incoherence even without universalizing their maxims. The key to understanding why Kant does not consider contracts of slavery as null and void for moral reasons lies in grasping how our maxims can be incoherent even without universalizing them.
O’Neill suggests that there are basically two ways in which a maxim may be incoherent without universalizing. First, there may be an internal inconsistency within a maxim (O’Neill Reference O’Neill1990: 89). Second, contradictions may exist between our intentions that are more specific than our maxims or between a specific intention and a maxim (ibid.). These two types of incoherencies resemble the incoherencies that arise in cases in which we attempt universalizing morally unworthy maxims that cannot be universalized. For this reason, to distinguish these two sets of incoherencies from each other, O’Neill uses the labels ‘conceptual inconsistency’ and ‘volitional inconsistency’ for incoherency maxims may have even without universalizing (ibid.).
O’Neill’s discussion of conceptual inconsistency is more important for my purposes than her consideration of volitional inconsistency. To put it briefly, volitional inconsistencies result from acting on maxims that are incompatible with what O’Neill calls ‘the Principles of Rational Intending’ (O’Neill Reference O’Neill1990: 91). The most important principle of rational intending is Kant’s Principle of Hypothetical Imperatives, which says that ‘whoever wills the end also wills (insofar as reason has decisive influence on his actions) the indispensably necessary means to it that are within his power’ (G, 4: 417). A maxim is volitionally inconsistent when it involves willing an end without willing the necessary means to achieve it.
Maxims that suffer from conceptual inconsistency express, in O’Neill’s terms, an impossible aspiration (O’Neill Reference O’Neill1990: 89). O’Neill states:
An agent’s maxim might be said to involve a conceptual inconsistency if the underlying intention was, for example, both to be successful and to be unworldly, or alternatively, to be both popular and reclusive, or both to care for others and always to put his or her own advantage first, or both to be open and frank with everybody and to be a loyal friend or associate, or both to keep a distance from others and to have intimate personal relationships. (O’Neill Reference O’Neill1990: 89)
The problem with such maxims is that they involve commitments that cannot be realized simultaneously. Obviously, maxims that are defective due to volitional or conceptual inconsistency fail FUL’s universalizability test. However, the way they fail FUL is essentially different from the way in which, say, a maxim of lying promise fails it. A maxim of lying promise fails FUL not because it is internally inconsistent but because it is inconsistent with its universalized counterpart. Such a maxim involves an inconsistency only if one attempts universalizing it. Making a lying promise is morally impermissible because of an inconsistency that arises only after one attempts universalizing it. The inconsistency of maxims that involve conceptual or volitional inconsistency arises because of a much more fundamental incoherence, which can be recognized even before one tries to universalize them. This is most apparent in conceptually inconsistent maxims. Conceptually inconsistent maxims are not universalizable not because they are immoral but simply because they do not make any sense. The question of whether conceptually inconsistent maxims are morally worthy or not does not even arise. To go back to an example O’Neill gives, it does not make any sense to ask whether the maxim of being both successful and otherworldly is morally worthy simply because it is fundamentally irrational. For these reasons, we should say not that such conceptually inconsistent maxims are immoral but rather that they are irrational and devoid of any sense. Their irrationality is different from the irrationality that Kant thinks morally unworthy maxims such as the maxim of a lying promise exhibit.
I suggest that, when Kant says in the Metaphysics of Morals that contracts of slavery are impossible and hence null and void, what he has in mind is mere conceptual inconsistency. This can be easily seen in the maxims adopted by the parties to such a contract. Consider the maxim of becoming a slave through a contract. It involves two inconsistent intentions that cannot be simultaneously realized. That maxim assumes that the ‘slave’ will have certain contractual rights as well as responsibilities arising from the fact that she is a person participating in a contractual relationship, but it also says that this same ‘person’ will be a tool that by its nature has no rights and responsibilities. In other words, a maxim of becoming a slave through a contract assumes both that an individual is to be treated as a thing and that she is a person subject to the provisions of the contract. It goes against the fact that a thing cannot at the same time be regarded as a person. Obviously, this inconsistency is a basic failure of rationality. Kant confirms this reading when he states that ‘no one can bind himself to this kind of dependence, by which he ceases to be a person, since it is only as a person he can make a contract’ (MM, 6: 330, emphasis added). Kant believes that contracts of slavery are null and void because they suffer from a very fundamental form of irrationality that arises without any attempt at universalization, not because they are immoral. Therefore, the fact that Kant says that contracts of slavery are null and void does not provide any evidence for Alexy’s thesis that, according to Kant, social norms can be legally invalid because of their immorality.
6.1 Kant on the relation between irrationality and immorality
My criticism of Alexy’s interpretation of Kant’s claim that contracts of slavery are null and void depends on the view that, according to Kant, not all instances of irrationality involve immorality. One can challenge the relevance of the distinction between conceptual and volitional inconsistency by arguing that, in Kant’s moral philosophy, irrationality equals immorality. If correct, this would undermine my interpretation of Kant’s claim about the nullity of contracts of slavery because I suggest that these contracts lead to irrationality without immorality.
It is a serious mistake to think that, according to Kant, irrationality equals immorality. To show this, I shall now briefly analyse some crucial features of Kant’s conception of a maxim and the Principle of Hypothetical Imperatives. This analysis will also serve to clarify further the above discussion about how maxims can be incoherent without universalizing them.
Consider Kant’s definition of maxim. In the Groundwork of the Metaphysics of Morals, Kant characterizes a maxim by saying that it is a subjective principle of action which ‘… contains the practical rule determined by reason conformably with the conditions of the subject (often his ignorance or also his inclinations) …’ (G, 4: 421, emphasis added).Footnote 16 That a maxim is determined by reason means that maxims must meet certain rational requirements and avoid irrationality when they are formed. What are the requirements of reason that must be met by a maxim? As Paul Guyer emphasizes, the principle of non-contradiction is a fundamental principle of reason as such (see Guyer Reference Guyer2019). Guyer is obviously correct. Kant states in the Critique of Pure Reason that ‘whatever the content of our cognition may be … the general though to be sure only negative condition of all judgments whatsoever is that they do not contradict themselves’ (A150/B189). Although the principle of noncontradiction is only negative in the sense that it is solely a necessary condition and not a sufficient condition of truth, all judgements must conform to it. And, since the principle of noncontradiction expresses a demand of reason, failure to comply with it amounts to irrationality.
Maxims that suffer from conceptual inconsistency are irrational in exactly this sense. Turning back to O’Neill’s example, a maxim that includes both the intention to keep distance from others and the intention to have intimate personal relationships violates the principle of noncontradiction and hence are fundamentally irrational. But does this case of irrationality involve immorality? Before considering Kant’s answer to this question, it should be noted that the correct answer to it is obviously negative. Epistemologically, we can adopt the normative principle that one must avoid holding beliefs that contradict each other. Such a principle is reasonable, but failing to follow it does not by itself constitute any immorality. A person whose belief system somehow includes the belief that Socrates is mortal and the belief that Socrates is immortal is not doing anything immoral simply because he holds these beliefs.
Kant agrees that failure to meet the principle of non-contradiction need not involve any immorality. To see this, recall Kant’s view that the object of moral evaluation is our maxims. Maxims are inputs to the test expressed by FUL. This means that, before a maxim can be a candidate for the test of FUL, it must first have a certain rational form. Only after a maxim has the required rational form can FUL be applied to it. And part of that rational form is constituted by the principle of non-contradiction. The maxims that appear among O’Neill’s examples of conceptually incoherent maxims do not have that rational form because they violate the principle of non-contradiction. Therefore, they cannot even be morally evaluated through FUL. Their irrationality arises before any immorality is identified through the employment of the Categorical Imperative. O’Neill’s examples for the conceptually incoherent maxims and the maxim that underlies contracts of slavery are irrational only in this way.
There are other cases of irrationality that Kant thinks do not involve any immorality. Turning back to Kant’s definition of a maxim, a maxim is a subjective principle ‘conformably with the conditions of the subject (often his ignorance or also his inclinations)’ (G, 4: 421n). Part of Kant’s idea here is that our maxims incorporate our inclinations and refer to their objects as the willed ends of our actions. In other words, at that stage of action in which we form a maxim, an end of inclination must be willed and must become part of the maxim. And Kant’s emphasis on the fact that our maxims conform to our conditions brings to the fore the Principle of Hypothetical Imperatives, which requires, as we saw earlier, that when we will an end in action, we must also will the necessary means available under the conditions in which we act. Since an end must be willed in the formation of a maxim, the Principle of Hypothetical Imperatives is an integral part of maxim formation. Just like the principle of noncontradiction, it is a rational requirement that must already be met at the stage in which we form a maxim to achieve a willed end before any question of immorality can be raised. This is to say that failure to comply with the Principle of Hypothetical Imperatives in the formation of a maxim leads to irrationality even before we can make any moral judgement about it through the Categorical Imperative. Such a failure is an instance of irrationality without immorality.
These points about Kant’s view concerning the relation between irrationality and immorality do not, of course, dispute the clear fact that, according to Kant, immorality is a form of irrationality. We see this in the Groundwork when Kant argues that the Categorical Imperative arises from pure reason (G, 4: 389). Since the Categorical Imperative demands that we act on universalizable maxims, that demand is a demand of reason. When we act on maxims that cannot be universalized, we act not only immorally but also irrationally.
7. Kant, Kelsen, and Hart
Having established that Kant adopts the positivist separability thesis, I shall now consider whether legal positivists themselves would consider Kant as a representative of legal positivism and which form of legal positivism Kant’s legal theory would be compatible with. My discussion of Kant’s normative legal positivism provides an answer to this question. Waldron is a leading legal positivist who adopts legal positivism in its normative variant and thinks that Kant also endorses normative legal positivism. This means that there is at least one prominent legal positivist who considers Kant as a legal positivist. As I argued above, Kant’s legal philosophy is not only compatible with normative legal positivism, but it also adopts it.
One might still ask whether classical legal positivists such as Kelsen and Hart would consider Kant as a legal positivist. This question is especially interesting in relation to Kelsen since Kelsen acknowledges Kant as an inspiration while refraining from counting Kant’s legal philosophy as an instance of legal positivism. He states that Kant’s ‘… philosophy of law is a typical application of the natural law doctrine’ (Kelsen Reference Kelsen1949b: 493). What inspires Kelsen in Kant’s philosophy is not Kant’s legal philosophy but his theoretical philosophy. As Stanley Paulson lays out, Kelsen uses a neo-Kantian transcendental argument to develop his pure theory of law which Kelsen thinks offers a third alternative to traditional legal positivism and natural law theory (see Paulson Reference Paulson1992, Reference Paulson2000).
That Kelsen distances himself from Kant’s legal philosophy makes sense because Kelsen is committed to ethical non-cognitivism. Kelsen states that ‘the problem of values is in the first place the problem of conflict of values, and this problem cannot be solved by means of rational cognition’ (Kelsen Reference Kelsen1957: 4). The problem of values, Kelsen argues, can be addressed only in terms of emotional factors. This is obviously in deep contrast with Kant’s legal theory. It is central to Kant’s legal philosophy that there are objective moral principles that are binding independently of our emotions.
Furthermore, Kelsen contrasts Kant’s theoretical philosophy with his legal philosophy in relation to legal positivism by arguing that ‘Kant, whose philosophy of transcendental logic was preeminently destined to provide the groundwork for a positivistic legal and political doctrine, stayed, as a legal philosopher, in the rut of the natural law doctrine’ (Kelsen Reference Kelsen1949a: 444). As this paper shows, Kelsen’s view that Kant’s legal philosophy must not be regarded as an instance of legal positivism involves a serious mischaracterization of Kant’s legal philosophy. Kant embraces the separability thesis and, to that extent, his legal philosophy is compatible with Kelsen’s positivism.
We should note that Kelsen’s understanding of natural law theory is also problematic. According to Kelsen, ‘all followers of the natural-law doctrine’ assert that ‘the positive law is … valid only insofar as it corresponds to the natural law’ (Kelsen Reference Kelsen1949b: 488, emphasis added). If this characterization of the natural law tradition is correct, all natural law theorists believe that moral merit is a necessary condition of legal validity. However, as Alexy’s classification of different versions of natural law theory shows, there are natural law theorists who do not think that morality is a necessary condition of legal validity.Footnote 17
Kelsen’s reading that, according to Kant, moral merit is a necessary condition of legal validity is implausible because he does not pay attention to the positivist aspects of texts like ‘What is Enlightenment?’. We see a similar problem in Eugenio Bulygin’s analysis of the Kantian dimensions of Kelsen’s legal theory. Bulygin argues that two incompatible groups of ideas guide Kelsen’s thought. On the one hand, a positivistic set of ideas lead Kelsen to embrace theses like the separation between ‘is’ and ‘ought’; on the other hand, a Kantian set of ideas is present in Kelsen’s theory (Bulygin Reference Bulygin, Bernal, Huerta, Mazzarese, Moreso, Navarro and Paulson2015: 237). Among them is a conception of validity as a binding force. The concept of validity as a binding force involves the idea that, if a norm is valid, ‘it is justified and ought therefore to be obeyed’ (p. 250). Bulygin rightly argues that the concept of validity as a binding force is incompatible with legal positivism because, according to legal positivism, the acceptance of a legal norm by an official as legally valid does not entail that it is obligatory (p. 246). As this paper shows, whatever the source of the conception of validity as a binding force in Kant’s theoretical philosophy, Kant’s legal philosophy is not committed to the view that the acceptance of a legal norm entails that it is justified and ought to be obeyed. In issues of legal philosophy such as legal validity, Kant’s legal philosophy should be given more weight than his theoretical philosophy.
Would Hart accept Kant’s legal philosophy as an instance of legal positivism? This question is more difficult since Hart, contrary to Kelsen, does not belong to the Kantian tradition. I believe, however, that it can be answered, at least indirectly, if we consider the distinction between inclusive legal positivism and exclusive legal positivism. This distinction arises from how legal positivists construe the separability thesis. All legal positivists believe that laws do not necessarily reproduce the requirements of morality. However, legal positivists disagree among themselves about whether there can be legal systems in which conformity with some moral criteria is a precondition of legal validity. Inclusive legal positivists believe that legal validity can sometimes depend on morality. Exclusive legal positivists deny this and argue that moral merit can never be a precondition of legal validity. Hart is an inclusive legal positivist as he thinks that ‘[i]n some systems, as in the United States, the ultimate criteria of legal validity explicitly incorporate principles of justice or substantive moral values …’ (Hart Reference Hart1994: 204).
We may shed light on the question of whether Hart would accept Kant as a legal positivist if we discover the extent to which Kant endorses inclusive legal positivism. I have already argued that Kant is a normative legal positivist. Since normative legal positivism is the view that laws ought to be such that their legal validity does not depend on considerations of moral merit, it assumes that legal validity can depend on considerations of moral merit. In other words, normative legal positivism presupposes inclusive legal positivism. Therefore, assuming that Hart takes inclusive legal positivism as the proper version of legal positivism, he would qualify Kant as a legal positivist to the extent that Kant presupposes the truth of inclusive legal positivism. Nevertheless, normative legal positivism does not only presuppose inclusive legal positivism, but it also prescribes exclusive legal positivism. Normative legal positivists believe that, even though legal validity may depend on considerations of moral merit, they argue that it ought never to be so (see Campbell Reference Campbell1998, Reference Campbell, Campbell and Goldsworthy2000, Reference Campbell2016; Schauer Reference Schauer, Spaak and Mindus2021). To the extent that Hart refrains from considering legal positivism as a normative account of how law ought to be, he would not count Kant as a legal positivist and Kant’s legal philosophy would not be compatible with his theory.
8. Kant’s super-inclusive non-positivism
If my analysis of Alexy’s interpretation is correct, Kant endorses the positivist separability thesis. Note that Kant’s endorsement of the separability thesis does not entail that he is not a natural law theorist since the separability thesis is compatible with super-inclusive non-positivism. While I believe that Kant adopts a version of super-inclusive non-positivism, elaboration of how Kant develops his own super-inclusive non-positivism goes beyond this paper. However, before I conclude, I shall briefly comment on Trivisonno’s interpretation. Drawing on Alexy’ tripartite classification, Trivisonno also thinks that Kant is a super-inclusive non-positivist (see Trivisonno Reference Trivisonno2011, Reference Trivisonno, Bellantuono and Lara2018). I believe that there is a significant problem in Trivisonno’s interpretation.
Trivisonno’s interpretation of Kant is based on a distinction between two connections between law and morality: a theoretical connection and the practical effects of this connection on legal validity. The latter is about the effects of moral defects on legal validity. If one believes that there is such a connection between law and morality, one holds that moral demerit leads to legal invalidity. On the other hand, Trivisonno says that a theoretical connection between law and morality stands for a ‘foundational and material connection’ (Trivisonno Reference Trivisonno, Bellantuono and Lara2018: 49). According to Trivisonno, if one holds that there is a theoretical connection between law and morality, one is committed to the idea that ‘the content of law has to be in accordance with morality’ (p. 49).
I find this distinction problematic because it is very hard to see its usefulness. Consider the fact that Trivisonno takes over this distinction from Alexy’s distinction between a classifying connection and a qualifying connection. A classifying connection between law and morality concerns the effects of moral demerits on legal validity. If one defends the existence of a classifying connection between law and morality, one endorses the idea that moral demerit leads to legal invalidity (Alexy Reference Alexy2012a: 6). As I mentioned above, a qualifying connection, according to Alexy, refers to the idea that moral defects in legal norms lead to a legal defect, not to legal invalidity (Alexy Reference Alexy and Dyzenhaus1999: 24).
The problem with Trivisonno’s distinction concerns the theoretical connection which he sees as corresponding to Alexy’s qualifying connection. Alexy uses the notion of a qualifying connection to characterize a feature of natural law theories that distinguishes them from legal positivism. He states that ‘non-positivism begins by defending a qualifying connection’ (Alexy Reference Alexy2012b: 104). According to Alexy, by endorsing the existence of a qualifying connection between law and morality, all natural law theorists believe that there is a necessary connection between moral defects and legal defectiveness. Alexy’s notion of a qualifying connection serves a useful distinguishing purpose since legal positivists reject the existence of any such necessary connection between law and morality. This rejection is simply part of their legal positivism.
Contrary to his intentions, Trivisonno’s notion of a theoretical connection between law and morality does not serve to establish any feature of natural law theory that would distinguish it from legal positivism (Trivosonno Reference Trivisonno, Bellantuono and Lara2018: 55). Recall that Trivisonno’s theoretical connection between morality and law stands for the idea that law must be in accordance with morality. As a legal positivist, Hart emphasizes that the positivist distinction between what law is and what law ought to be does not mean that legal positivism is not committed to any moral principle we can use to criticize existing laws (Hart Reference Hart1958: 595). This means that Hart thinks that there is a theoretical connection between law and morality in Trivisonno’s sense. Therefore, Trivisonno’s notion of a theoretical connection between law and morality does not suffice to distinguish natural law theory from legal positivism. Similarly, since there are natural law theorists who accept the separability thesis, concentrating on what he calls the practical effects of a theoretical connection between law and morality does not serve that purpose either. For these reasons, it is hard to understand why Trivisonno does not use Alexy’s distinction between a classifying connection and a qualifying connection and replaces it with a distinction of his own.
9. Conclusion
I would like to note that Kant’s views about the sheer conceptual inconsistency of contracts of slavery should not be confused with his clear moral stance against the practice of slavery in his moral philosophy. Consider first the formula of humanity of the Categorical Imperative. It explicitly condemns slavery because slavery is the most obvious case in which one is treated merely as a means. And FUL prohibits the practice of slavery as well. When universalized, the maxim of becoming a slave leads to a contradiction in conception since, in a world in which everyone is a slave, no one is a slaveholder, and this undermines the very practice of slavery (O’Neill Reference O’Neill1990: 96). Kant’s legal philosophy also identifies slavery as wrongful. Slavery is clearly inconsistent with our sole innate right to freedom (MM, 6: 237). It is the practice of slavery that Kant condemns morally, not contracts of slavery. The latter are simply irrational without immorality.
Acknowledgements
I thank Matthias Kaufmann, Kenneth R. Westphal, Mario Brandhorst, Heiner Klemme, Christoph Horn, and Hüseyin Kuyumcuoğlu for their help in developing this paper. I am grateful to two reviewers of Kantian Review for their insightful comments on an earlier draft.
