2. Eutopia

Utopias and dystopias have been used in philosophy and literature as tools of criticism that stem largely from a sense of injustice. As Orwell (Reference Orwell2014) describes his political and aesthetic writing in his essay Why I Write,

Writers like Orwell deploy utopias or dystopias as “strategies for addressing difficulties human beings face in determining what morality and justice require and in realizing these demands in worldly circumstances” (Holtman, Reference Holtman2003, 77). Utopian projects, according to Sarah Holtman, are useful not only insofar as they exemplify our political and social aims—for instance, Kant’s cosmopolitan state is a civil union in which external freedoms can coexist in the most perfect way—but also because they help us to identify the obstacles that our current societies must navigate to realize them (Holtman, Reference Holtman2003, 84).

However, a utopiaFootnote ³ is often understood as an ideal plan that is difficult or even impossible to realize, and utopias are frequently characterized as illusions, dreams,Footnote ⁴ and fictions. Scholars critical (Baier, Reference Baier1985; O’Neill, Reference O’Neill and Evans1988) of utopian theories and their use of abstract concepts and principles are right in emphasizing not only the difficulty or impossibility of applying them to concrete cases but also the errors they might lead to, for instance, to name only two possibilities, misrepresenting the status quo or imposing from above a notion of the good place that is both too specific and arbitrary. These utopian theories might well be hardly distinguishable from dystopias. A notorious example is Kurt Vonnegut’s thought experimentFootnote ⁵ in the short story “Harrison Bergeron,” which describes a futuristic late 21st-century American society that considers equality to be the only absolute value. He describes the citizens as follows: “They were not only equal before God and the law. They were equal every which way. Nobody was smarter than anybody else. Nobody was better looking than anybody else. Nobody was stronger or quicker than anybody else” (Vonnegut, Reference Vonnegut2010, 7). The identification of something as an absolute good—in this case, the idea that everyone is equal to everyone else in all respects—transforms what was meant to be a utopia into a dystopian society. Once a particular conception of the good life is established as definitive and no alternatives are admitted, freedom becomes impossible. However, although these criticisms directed at utopian idealizations have legitimate grounds, they risk the complete rejection of the usefulness of idealizations. Therefore, I believe that reformulating “utopia” as “eutopia” (εὔτοπος, “good place” in Greek)Footnote ⁶ can help free these idealizations from their common and immediate association with mere daydreaming as well as with the dystopias they might generate. “Eutopia” emphasizes the positive normative dimension of an ideal without carrying these pejorative connotations. By adopting this term, I seek to dissociate the idea of the good place from the widespread assumption that it is necessarily unrealizable. That a plan to constitute a good place might be challenging to realize does not make it a mere fable.

There are at least two related ways in which Kant can help us imagine a eutopia. One is to look for exemplifications of ideal constitutions within his theory—namely, the ethical community and perpetual peace. The other is to focus on his anthropological theory (concerning the predispositions to the good in human nature) and use it to frame an image of eutopia. I claim that the two are connected, because what makes the former cases of eutopia is that they represent a social and political order that secures the social, material, and institutional conditions for the flourishing of Kant’s three predispositions to the good, under some constraints. I am not claiming that Kant’s theory did this successfully; its eurocentrism, racism, and paternalismFootnote ⁷ signal its potential as the foundation for a dystopia in which only certain people can access and benefit from the conditions required for the flourishing of the predispositions.Footnote ⁸ However, if we agree with his account of the predispositions to the good and we believe that an idea of eutopia is needed—at least, as a critical tool to read our status quo—then we can still make productive use of his theory.

3. A Kantian Eutopia

In Religion Within the Limits of Mere Reason, Kant, discussing whether human nature is good or bad, provides an answer by introducing the original predispositionsFootnote ⁹ to the good and the propensity to evil. The propensity to evil, although presented as a universal characteristic of our species (RGV 6:25, 30, 32–33) that cannot be eradicated (RGV 6:31), can nevertheless be thought of as acquired, insofar as it is contracted through free choice (RGV 6:29). In a different way, the original predispositions to the good—which are the foundations of the dispositions (the reasons we adopt a maxim)—are called “original” because they “belong to the possibility of human nature” (RGV 6:28). That is to say, if we had to describe the constitutionFootnote ¹⁰ of the being human, we would have to use the three original predispositions. These, as has already been pointed out, are directed toward the good; as Kant writes, “All these dispositions in man are not only (negatively) good (not in conflict with the moral law), but they are also dispositions to good (promote the pursuit of it)” (RGV 6:28).

In particular, the first original predisposition, the predisposition to animality (Tierheit), considers the human as a living being: it refers to a natural and mechanical self-love, realized by self-care, and the preservation of the species and life in community. The second, the predisposition to humanity (Menschheit), has to do with the pursuit of happiness and the choice of means, through an instrumental use of our rationality, to achieve it. The third original predisposition, to personality (Persönlichkeit), is defined as “the susceptibility of respect for moral law as a motive, sufficient in itself, of the will” (RGV 6:27). In other words, the predisposition to personality indicates the subjective ground for the subject’s adoption of the moral law as the sole motive: if I am to adopt the moral law, I must be capable of adopting it, and the “germ” that explains this possibility is the predisposition to personality. The peculiarity of the original predisposition to personality consists in the fact that, unlike the others, it cannot be corrupted: as Kant explains, “There must be present in our nature a predisposition upon which absolutely no evil can be grafted” (RGV 6:28). Although we do not always act morally, the incorruptibility of the original predisposition to personality means that we can always change our current way of going about life—that is, we can change our maxims.

Now, if the human being can be described as attempting to develop their predispositions while constantly struggling with their propensity to evil, then the eutopia correspondent to this anthropology should be a place in which there are material, social, and institutional conditions that provide the best terrain for both the flourishing of these predispositions and the struggle against the propensity to evil. To help in the struggle against the propensity to evil, Kant introduces the ethical community. Because, as we see the discussion of the ethical community in the later text, we humans constantly compare ourselves with others and corrupt one another, a eutopia would offer a place in which we could influence one another toward the good. Because freedom is not only internal—that is, it does not concern only our maxims and our pursuit of virtue—but also external—it concerns our actions and exercise of power in the world—certain constraints are needed to organize the exercise of everyone’s external freedom in the most harmonious way such that we are at least on the pathFootnote ¹¹ toward eutopia. The determination of concrete constraints or laws regulating the use of external freedom must be grounded on three fundamental principles: first, the universal principle of right, which states that an action is right if “it can coexist with everyone’s freedom in accordance with a universal law” (MS 6:230); second, the principle of publicity: a law must be capable of being freely willed by those subject to it and therefore cannot depend upon secrecy (WA 8:39; ZeF 8:381)Footnote ¹²;and third, legislation must conform to the maxims of the common human understanding, that is, the most general principles governing correct judgment and protecting us against prejudice and error (KU 5:294ff.; Log 9:57; Anth 7:228–229).

My purpose here is not to examine these three principles in detail, nor to discuss Kant’s Doctrine of Right as a whole; rather, I call attention to the extension of the Doctrine of Right to the international sphere, namely through both the preliminary articles of perpetual peace and the theory of the ethical community. I argue that the eutopian models presented therein are best understood as ideas in the strict Kantian sense: products of reason that provide both a normative standard for criticism and a goal for political and social practice. They enable us, on the one hand, to identify deficiencies in existing institutions—for example, the absence of the material conditions necessary for the flourishing of the three human predispositions—and, on the other hand, to orient efforts toward their progressive realization. Because ideas, as concepts of reason, cannot be exhibited directly in sensibility, they require analogues of schemata: sensible, though necessarily imperfect, representations that make them practically meaningful. I shall now turn to these theoretical notions before showing how they illuminate the two Kantian eutopias examined in this article: the ethical community and perpetual peace.

4. Schematism

Schematism has often been considered the most complex and obscure part of the Critique of Pure Reason. Hegel refers to schemata as artificial, lifeless constructions (Hegel, Reference Hegel1968, vol. 7, 36); Herder regards them as a fiction among fictions (Herder, Reference Herder1799, 418); Schopenhauer states that no one has ever been able to make sense of the schematism (Schopenhauer, Reference Schopenhauer1844, 574). In my view (Scaglia, Reference Scaglia2020, Reference Scaglia, Clusa, Laos, Martínez, Oroño, Reyna, Scaglia and Straulino2024), however, schematism can and should be regarded as a fundamental step in Kant’s inquiry, first and foremost because it is this section of the Critique that addresses the conditions of possibility of experience (and not just of thought). Let me clarify this by distinguishing schemata from concepts, focusing on pure concepts in particular.

In Kant, all concepts are abstract, insofar as they are general representations, but some concepts can be used concretely (Log 9:99)—that is, they have empirical use, insofar as they refer to objects of possible experience. Pure concepts, or categories, constitute a special class of concepts that, although they do not derive from experience, are meaningful only in relation to experience. Categories are the universal and necessary rules of thinking; they express the formal universal structure of our thought, without which it would be impossible to make any kind of judgment. Considered alone—that is, apart from their cooperation with sensibility—pure concepts (i.e., categories) allow for the thought of a logical object, sometimes addressed to as an object in general—namely, the highest genus of all objects (A290/B346). Such summus genus of all objects, however, is not a possible object of experience, represented in time and space, but rather the mere thought of a formal unity according to the categories.

Schemata, in contrast to concepts, are conditions that allow us to perceive certain objects in all their complexity, their relations, and their possible properties. They are not pure concepts of the understanding but rather their temporal translations, which represent the cooperation of both sensibility and understanding, insofar as their forms are considered. That is to say, although, for example, the category of substance is the condition necessary for thinking about something that is always a subject and never an attribute (A147/B186), it is not sufficient to constitute a condition of experience because it lacks the temporal character necessary for constituting experience. According to this interpretation, then, pure concepts are not, in themselves, the conditions of experience but only of thought. Kant clarifies,

Given that our kind of cognition needs experience—and not just mere thinking—and that experience is always, at least, given in time, something must be represented as permanent in time to be an object of possible experience. As fundamental rules for the unity of thinking, then, categories require the cooperation of sensibility and its pure form of time to be meaningful—that is, to have some content beyond that of a merely logical object. Categories therefore need to be restricted to the form of time.Footnote ¹³ From this kind of temporal translation of categories, the list of schemata is derived. It is not my aim here to explain in detail how each schema works or how they differ from one another; rather, I limit myself to explaining how the transcendental determination of schemata constitutes experience.

This transcendental schematic determination means, first of all, that a variety of perceptions forms a whole (a musical theme, a book, or even the plot of a dream). This whole is made available to the imagination, which guides the recognition of sensory data. Second, this perception is not disordered; rather, it is organized temporally. Finally, there is a transcendental determination when temporal apprehension takes place according to an objective rule of unity, that is to say, according to the categories. Thus, these time relations have an intersubjective validity grounded in pure concepts (see Allison, Reference Allison2004, 216–217). Although categories refer to logical objects, schemata refer to possible objects of experience. The level of schematic transcendental structures is the most basic, and it is presupposed in all kinds of experience, including experiences of objects whose natures we do not yet know, which we cannot yet clearly define or identify for the lack of a more specific apparatus of empirical concepts. In this sense, this is not an idealist proposal defending the impossibility of experiencing what we cannot determine through empirical concepts. Rather, it is a form of transcendental idealism that sees in the schemata the minimal conditions of experience.

As it is developed in the following sections, the notion of a schema helps us understand why Kant’s political ideas of the ethical community and perpetual peace are better understood as eutopias rather than utopias. In the case of the ethical community, for example, partial societies, including the visible church, can be understood as intermediate steps toward the realization of the ethical community. Similarly, Kant’s idea of perpetual peace reveals a distinctly eutopian dimension. The mere existence of laws whose implementation cannot be immediate because of the prevailing political circumstances shows that Kant is not simply presenting an ideal yet unrealizable world. Rather, he opens—albeit within certain limits—a path that begins from the actual world: an imperfect world devastated by the wars of his time and resistant to reforms that can initially be realized only through partial steps toward better political and social forms of coexistence. This point is crucial for understanding Kant’s political projects from a eutopian perspective. To imagine a eutopia does not merely mean envisioning a perfect moral, social, or political order; rather, it means dealing constantly with imperfection and conceiving of the existing order as a starting point and as a stage in a possible progression toward a better one.

Having clarified what schemata are, we can now explore a conceptual notion that is essential to our inquiry: ideas.

5. Ideas

Unlike the pure concepts of the understanding—which in their cooperation with sensibility through the schemata constitute the possibility of experience—ideas are defined as concepts of reason that transcend experience (A320/B377). Ideas cannot have any correspondence in the realm of objects of possible experience: Kant explains, “I understand an idea to be a necessary concept of reason to which no congruent object can be given in the senses” (A327/B383).

The Critique of Pure Reason, Critique of Practical Reason, and Critique of the Power of Judgment identify various kinds of ideas: from transcendental ideas—concepts “of the totality of conditions for a given conditioned thing” (A322/B379), given by the nature of reason itself (A327/B384)—to practical and aesthetic ideas. Ideas, in their theoretical use, serve as guides to organize our inquiry according to the highest possible unity; that is, they provide direction for systematizing our cognitions in the most coherent way. In discussing Plato’s ideas, regarded as archetypes, Kant explains that they are models (e.g., the idea of virtue). We can find examples of these models in experience, although such examples are never fully adequate to the ideas themselves. This lack of empirical adequacy, however, does not mean that such ideas are mere deceptions or illusions: in Kant’s words, “That no human being will ever act adequately to what the pure idea of virtue contains does not prove in the least that there is something chimerical in this thought. For it is only by means of this idea that any judgment of moral worth or unworth is possible” (A315/B372).

The idea of virtue is a necessity for reason: we do not need empirical evidence to confirm its realityFootnote ¹⁴ because it is not a concept that aims at representing an object of experience. Rather, the idea of virtue represents a moral status, a status that is per se intelligible. Because of this idea, it is possible to judge moral worthiness: when our moral judgments are structured in such a way that the moral law has priority over other incentives, such as self-love, then we are on the right path toward virtue and moral perfectibility. However, virtue is not the only idea that does not require an empirical ground. Another example that can fit our account of eutopia (at least according to some interpretations) is the Platonic republic—or, more generally, the idea of a perfect political constitution as Kant describes it:

What is particularly significant about this passage is that it confirms precisely the point I have been defending regarding utopia. The term “utopia” is frequently associated with dreams, illusions, or impossible ideals, and precisely because it lacks an empirical counterpart, it is often dismissed as politically or philosophically irrelevant. Kant, however, argues the opposite. The idea of a perfectly rightful constitution is a necessary idea of reason: without an idea that sets before us the goal of a constitution in which the greatest possible freedom is united with universal law, we would have no standard by which to guide political progress. Such an idea serves both as a regulative goal and as a critical standpoint from which existing institutions can be assessed. To dismiss it as a mere dream would therefore be deeply harmful, for it would deprive us not only of the motivation to improve our political and social institutions but also of one of our most important critical tools for recognizing their deficiencies. Just as the idea of perfect virtue enables us to evaluate our own moral conduct, the idea of a perfectly just constitution provides the normative standard by which existing constitutions can be judged. Having clarified these conceptual tools, I now turn to their use in two Kantian eutopias: the ethical community and perpetual peace.

6. The Idea of the Ethical Community and Its Schema

The first example I want to consider is the often-neglected description of an ethical community in the Religion Within the Boundaries of Mere Reason. This work can be read both as an experiment comparing Christian doctrine with a system of pure religion according to reason and as a complement to Kant’s ethics insofar as it develops what we shall see to be the social dimension of ethics. It is divided into four books that were originally conceived as separate essays. The first is devoted to original sin, radical evil, and the original predispositions toward the good; the second concerns the struggle between the evil and the good principles within human nature; the third addresses the victory of the good principles; and the fourth deals with priestcraft as both proper and counterfeit service. As Pasternack interprets them, the first two books concern the journey of the individual toward the Highest Good, whereas the last two concern the social and historical dimensions of its realization (see Pasternack, Reference Pasternack2014, 6–12). At the same time, although the first and last books focus on corruption (radical evil and counterfeit service), the second and third concern redemption. More precisely, although the second book introduces the revolution of the heart (RGV 6:47; 6:67; 6:75) by which the individual changes their fundamental disposition from evil to good, the fourth describes the ethical community, on which I now focus.

On a Rousseauian note, Kant claims that human beings influence one another in such a way that they become instruments of evil:

In an ethical state of nature, where human beings are not associated under ethical laws, we inevitably drift toward evil because we are constantly comparing ourselves according to external standards (money, recognition, success, etc.). These comparisons lead us to regard the standards as the only goals in life, disregarding our deepest intentions. Given the inevitability of social pressure, Kant aims to turn things around: because we cannot avoid influencing one another, we should positively influence one another and help each other in the pursuit of virtue. That is, we should strive to build an ethical community, “an association of human beings merely under the laws of virtue” (RGV 6:94). Although Kant’s practical theory is often regarded as exalting individualism, in these passages, he clearly states that virtue cannot be achieved without a collective striving toward it: “This highest moral good will not be brought about solely through the striving of one individual person for his own moral perfection but requires rather a union of such persons into a whole toward that very end” (RGV 6:97). This association of the whole of humanity under the law of virtue is also called an invisible church, which serves as a model or archetype for historically existing churches. Following the table of the categories, Kant ascribes to the invisible church the features of (1) universality (quantity), understood as a necessary principle of morality that does not allow for divisions and schisms; (2) purity (quality), a way of orienting that admits only moral incentives, not superstitious and other heteronomous principles; (3) freedom (relation) both among the members of the invisible church and in its relation to political power; and (4) an unchangeable constitution (modality), with the exception of its administration, which must adapt to historical changes (RGV 6:101–102).

This ethical community is described by Kant as an “idea,” which has “objective reality in human reason (in the duty to join such a state), even though we cannot subjectively ever hope of the good will of human beings that these will work harmoniously toward this end” (RGV 6:94–95). As mentioned previously when discussing Kant’s comments on the idea of a perfect state, the ethical community is necessary insofar as reason produces it by projecting a maximum of unity of virtue in an imagined (not yet realized) object: the ethical community itself. This, however, does not mean that we humans can expect our wills to cooperate in pursuit of the ethical community; indeed, given the lack of transparency of our own hearts (GMS 4:407), we cannot even be sure that our own wills will be directed toward this end. Still, because reason produces the idea of the ethical community, we must regard it as both a real possibility and a duty imposed by reason.

Now, if the ethical community is the goal—the idea insofar as it is conceived as a community including all of humanity—and it cannot be realized in its totality at any determinate time, then intermediate steps or mediating phases are required to achieve it. This is where the notion of a schema comes into play:

Partial societies—that is, societies in which the whole of humanity does not yet belong to the ethical community (or to a league of nations aiming at perpetual peace)—can be regarded as schemata, insofar as they function as a kind of middle term between the ethical state of nature and the ethical community. Using an analogy, if the ethical community is the pure concept (in this case a concept of reason, i.e., an idea) and the ethical state of nature corresponds to sensibility (an imagined raw condition lacking unity and laws), then the partial societies striving toward the whole of the ethical community are middle terms. Like schemata, they are both sensible and intellectual: they are limited and finite communities (like sensibility, which does not provide totality), but they are united under a law of virtue that, just as the categories do, provides them with unity.

If one were to ask which kind of community or church Kant had in mind while writing about such a partial society, the answer is clear: the Christianity of his time. We can derive as much from the following passage:

Here, it is important to emphasize that precisely because they are not yet the full realization of the idea (the ethical community), these communitiesFootnote ¹⁵—as well as the actual state of Christianity in Kant’s time—are mere analogies of a schema and not properly schemata. As Kant explains in a footnote, because ideas are products of reason to which everything sensible (i.e., everything that is schematized) is inadequate, we can never take a sensible object to be an adequate representation of an idea. In Kant’s example—which also applies to the partial societies that are on the path toward the ethical community—the Son of God who sacrifices himself for the love of humanity should not be taken as a sensible object perfectly adequate to the idea of virtue but rather as a mere analogy of it:

In other words, our reason needs to imagine a path toward virtue, but this does not mean that the imagined path is an object of experience perfectly adequate to the idea we are pursuing. However, given the introduction of the notion of analogy, one might wonder why Kant speaks of schematism rather than symbolism. Symbols, unlike schemata, are indirect presentations or exhibitions of a concept by means of analogy (KU 5:352). In Kant’s example, a body is a symbolic representation of a monarchic state because it is constituted by the organization of its members: even if both a monarchy and a body have a head, this head does not rule over the rest of the members despotically by making them mere inert tools at its service.

I believe that the answer to the question of why Kant alludes to schematism rather than symbolism lies in the fact that, at least in the case of the ethical community, the partial societies or the visible church are not merely analogies that help us to understand what an ethical community would look like. Rather, they must be taken as middle terms or intermediate steps toward it.Footnote ¹⁶ In this sense, the partial societies are somewhat more than analogical representations: they are actual steps toward the realization of the ethical community. This point is again important for understanding how they can be interpreted from a eutopian perspective. To imagine a eutopia does not mean merely to dream about a perfect moral, social, and political constitution but rather to regard our status quo as a step toward it. We must believe that we are already on the path toward the realization of the idea—even if our current condition is still far from it—to realize it. In other words, we must take responsibility: we must care for our world to make it better.

7. Ideas in Toward Perpetual Peace

I now focus on a second eutopian example that makes use of the notion of idea: the project presented in Toward Perpetual Peace.

Kant’s essay can be read as an attempt to defend the pacifist project of the Abbé de Saint-Pierre (Reference de Saint-Pierre1713, Reference de Saint-Pierre1717) against the criticisms of another major pacifist of the time, Rousseau. In his Jugement sur le projet de paix perpétuelle, Rousseau accuses Saint-Pierre of failing to present practical means for realizing peace in Europe. Kant aims to do better by presenting a clear account of the main conditions required for the realization of perpetual peace. These conditions are set out in the preliminary articles, which are divided into strict laws (leges strictae; numbers 1, 5, and 6), which have to be applied independently of particular circumstances, and wide laws (leges latae; numbers 2–4), the applications of which may be postponed due to particular historical circumstances, though not to an indefinite or nonexistent date (ZeF 8:347).

I do not discuss the preliminary articles in detail; instead, I offer a few examples of how they can be interpreted from a eutopian perspective, understood as measures aimed (although Kant never states this explicitly) at creating the best possible conditions for the flourishing of humans’ three original predispositions.

A first example is the third preliminary article, which calls for the abolition of standing armies (ZeF 8:345). Such an abolition not only prevents physical harm and thereby contributes to the preservation of our predisposition to animality but also safeguards our humanity by preventing human beings from being treated as mere means. As Kant writes, “Being hired to kill or to be killed seems to involve a use of human beings as mere machines and tools in the hands of another (a state), and this cannot well be reconciled with the right of humanity in our own person” (ZeF 8:345). The “right of humanity in our own person” may be understood as a reformulation of the formula of humanity, according to which persons must never be treated merely as means. In the terminology of the Religion, this requirement is grounded in the predisposition to personality: human beings are constitutively susceptible to respect for the moral law, and being employed as instruments of war is fundamentally at odds with this predisposition.

Further examples can also be drawn from the first and sixth preliminary articles. The former states that “no treaty of peace shall be held to be such if it is made with a secret reservation of material for a future war” (ZeF 8:344), whereas the latter maintains that “no state at war with another shall allow itself such acts of hostility as would have to make mutual trust impossible during a future peace” (ZeF 8:347). From a eutopian perspective, both articles aim to secure the conditions under which the predisposition to personality can flourish. Secret reservations in peace treaties violate the duty of truthfulness, which Kant describes as “the greatest violation of a human being’s duty to himself regarded merely as a moral being” (MS 6:429). Public deception, no less than private lying (although this is not here in question), has its costs: it undermines the moral conditions of social life by eroding the mutual trust on which peaceful coexistence depends. Likewise, acts of hostility that make future reconciliation impossible destroy the very conditions under which an ethical community could emerge.

Moreover, both articles express the principle of publicity, which, as argued previously, functions as a negative test of the legitimacy of political maxims. If a treaty or political reservation can only be maintained in secret, this is because it serves heteronomous and particular interests rather than principles that could be publicly justified before all rational agents. In this respect, the prohibition of secret clauses is not merely a prudential requirement for lasting peace but also a moral condition for the realization of a political order compatible with autonomy.

Although the preliminary articles formulate the negative conditions for the possibility of perpetual peace by prohibiting practices that undermine the flourishing of the predispositions, the definitive articles provide its positive institutional counterpart. They can be understood as successive approximations to the eutopian idea of perpetual peace. As with the ideas of reason discussed in the Critique of Pure Reason, perpetual peace is not a description of an existing state of affairs but a regulative ideal. The definitive articles therefore identify the juridical and political conditions through which this idea can progressively acquire objective reality. Rather than depicting an already existing political order, they establish the institutional framework that ought to guide humanity’s continual approximation to the highest political good.

More specifically, the first definitive article establishes that the civil constitution of every state must be republican (ZeF 8:349). According to Kant, perpetual peace can be achieved only among states whose constitutions separate legislative and executive powers and are grounded on three principles: the freedom of the members of society, the dependence of all upon a single common legislation, and the equality of citizens (ZeF 8:349–350). Kant further maintains that such a republic may assume the form of a monarchy,Footnote ¹⁷ provided that the monarch governs through representative institutions. Because political representation can be exercised more effectively when executive authority is concentrated, this constitutional arrangement facilitates the gradual introduction of reforms while preserving republican principles.

From a eutopian perspective, a republican constitution provides the institutional framework within which the predispositions can develop. By contrast, under a despotic constitution, where citizens are denied equality before the law and legislation is determined by the arbitrary will of the ruler, political institutions are more likely to embody heteronomous rather than autonomous principles. Such a political order undermines the conditions required for the flourishing of the predispositions: if equality is not recognized, for example, some individuals may be treated as possessing less worth than others, thereby legitimizing forms of discrimination.

The second definitive article establishes that international rights should be based on a federation of free states (ZeF 8:354). In the same way that individuals must leave the state of nature and enter into a civil constitution, states too must form a Völkerbund, a league of nations that is to be regarded as pacific (foedus pacificum) because it seeks to end all wars. This league, which does not aim to acquire power over states but merely to preserve their freedom, is presented as an idea endowed with objective reality:

Strictly speaking, however, what possesses objective reality here is not the fully realized condition of perpetual peace but the practical possibility of progressively approaching it through the establishment of a federation (see Tundo Reference Tundo1998, 184ff). The federation itself is not the ultimate ideal of reason but a historical approximation of it. The regulative ideal remains a universal juridical community—a Weltrepublik in which the very conditions that give rise to war would gradually disappear: a eutopia in which there are no boundaries and in which, perhaps, even the very idea of a state will have no reason to be. Yet because states are unwilling to renounce their sovereignty,Footnote ¹⁸ reason must content itself with a voluntary league of nations, which is merely the “negative surrogate” of a world republic. Because states do not want to give up their freedom and, in a sense, their identity, we can only aspire to a league as the negative idea of a world republic—that is, a cosmopolitan state of all nations:

A further occurrence of the notion of idea appears in the third definitive article, which concerns the right to cosmopolitanism.Footnote ¹⁹ This right is grounded not in a universal right to hospitality (Gastrecht) but in the more limited right of visitation (Besuchsrecht). Because all human beings inhabit the same spherical earth and “originally no one had more right than another to be on a place on the earth” (ZeF 8:358), every person possesses a right to present themself peacefully to others. The point is not the distribution of property but the possibility of lawful interaction (commercium) among peoples (MS 6:352) and, more fundamentally, the right to have access to full rights wherever one is born. As commercial and political relations become increasingly global, violations of right can no longer remain merely local affairs; an injustice committed in one part of the world affects the juridical order of humanity as a whole:

Kant therefore presents cosmopolitan right not as an optional moral aspiration but rather as a necessary complement to both constitutional and international right.Footnote ²⁰ It extends the juridical order beyond the state and the federation, thereby bringing humanity one step closer to the regulative ideal of perpetual peace.

The final occurrence of the notion of idea appears in Kant’s conclusion, where perpetual peace is described not as a mere wish but as a task imposed by practical reason:

This passage recalls Kant’s remarks in the Critique of Pure Reason concerning the systematic unity of reason. Just as reason necessarily projects the idea of a complete systematic unity in theoretical cognition, practical reason necessarily projects the ideal of perpetual peace as a task that guides political action. From a eutopian perspective, perpetual peace is therefore neither a prediction nor an unattainable daydream; rather, it is a regulative idea that orients historical progress. To dismiss it as a mere dream would be “harmful” (A317/B374), as Kant also says of the ideas of reason, for it would deprive political practice of the normative horizon by which existing institutions can be criticized and progressively reformed.