In this book I have proposed a Kantian view which includes animals in moral concern, not by adding a new line of reasoning to the existing Kantian corpus, but by making changes to Kant’s conception of moral concern. The resulting system, called Kantianism for Animals, retains core features of Kant’s views in moral philosophy: As rational beings, we autonomously impose the moral law on ourselves. This law marks out two ends as obligatory, namely others’ happiness and our own moral perfection. From these obligatory ends, we can derive materially specific duties. In these respects, nothing at all has been changed about Kant’s philosophy. However, Kantianism for Animals is a somewhat unorthodox version of Kantianism in three respects:

First, it views the Formula of Humanity, along with other formulations of the Categorical Imperative, not as a substantive moral principle, but purely as a formal principle of autonomous willing. It is not a principle to which we should turn in order to arrive at specific ethical action-guidance. Frankly, the Categorical Imperative plays only a minor role if our interest lies in determining what a good will wills, not how it wills. To arrive at specific action-guidance, we should move from the idea of a good will to the doctrine of obligatory ends, and from there to specific ethical duties. The crucial question when it comes to animals is therefore not ‘Are they ends in themselves?’, but rather, ‘Should their happiness be promoted as part of the obligatory ends?’ As I hope to have shown, it is much easier to argue for an affirmative answer to the latter question than to the former.

Secondly, any ‘second-personal’ element has been removed from Kant’s system. The existence of duties towards others does not depend on the capacity to ‘constrain’ each other under a mutually shared moral law. Kantianism for Animals locates the normative basis of our duties in the autonomy of the moral agent alone, with none of the normative work being left to any supposed authority of others. Duties are directed ‘towards’ others, on the alternative view I have put forward, simply in the sense that they are duties derived from the obligatory end of the happiness of others. So the directionality of our duties hinges on what they ask us to do and why. Admittedly, this conception does not produce exactly the same upshots as more second-personal approaches when it comes to moral practices like consenting, apologising, and forgiving. But the differences are smaller than one might expect, and they are not obviously objectionable.

Third, some changes were made to Kant’s conception of duties to others. The type of duty to others which could only plausibly hold vis à vis human beings—duties of respect—was recategorised as a duty to self, merely regarding others. It is basically a duty not to exalt ourselves above others, and this duty we must observe even in our beneficence towards others. Finally, an expansion was made to Kant’s conception of animal agency. Although animals do not pursue their happiness as a matter of instrumental reason, they have a greater extent of goal-orientation than Kant acknowledged. The goals they pursue also indicate their happiness, even if they are not purposefully chosen as means to happiness. Hence, duties of love towards animals, like Kant’s duties of love to human beings, demand primarily that we help along another’s self-chosen endeavours. This retains the anti-paternalistic flavour of Kant’s account of beneficence.

One aim of this book was to show that the deviations it takes to make Kantianism include animals in moral concern are more peripheral than one might think. We need not abandon the core of Kant’s system, such as the view that morality arises from autonomy, not pleasure and pain, or compassion. The most substantial point of disagreement with Kant is on an issue he himself only considers in passing, namely his account of interpersonal ethical obligation. As long as we insist that such obligation exists only given mutual ‘necessitation’ or ‘constraint’ under a shared moral law, animals will inevitably be excluded from the moral universe. But nothing more central in Kant’s ethical system forces us to adopt this view. With the purely first-personal view, an alternative is open to us. So Kant is much closer to including animals in moral concern than animal ethicists often suppose.

The other aim was to provide a novel system to animal ethicists that helps them reflect on our moral relations to animals. Kant’s moral philosophy amounts to more than a claim. It comprises its own set of questions, answers, notions, distinctions, and arguments. It lays different emphases and tells different stories than other approaches. My hope is that having this approach in the philosophical toolbox will help to advance the thought of animal-friendly ethicists and philosophically interested animal advocates.

At the outset of this book, I have characterised its approach as constructive and revisionist, and I have presupposed a radical agenda. It is an approach that treats Kant not as a philosophical authority, but as a philosophical resource. Hopefully, the project can serve as a proof of concept for this kind of approach to the canon. In principle, one can apply it to any and all philosophers, particularly to those whose thought is usually understood to be highly systematic, but inimical to the moral claims of animals. Why not take the same approach to Spinoza, for example?Footnote 1 Or Habermas?Footnote 2 Or Rawls?Footnote 3 Having applied the approach to Kant, let me highlight some reasons why this research programme could be worthwhile.

First, recall that one motivating reason for this project was that Kant’s moral philosophy should not be left to those who want to diminish or dismiss the moral claims of animals (see Chap. 1). I hope to have shown that Kant’s exclusion of animals does not stem from what is usually considered to be the core of his system. In particular, the view that morality arises from autonomy does not commit us to Kant’s claim that there can be duties only towards autonomous beings. If we prefer, we can even double down on Kant’s view that the moral law is autonomously self-imposed to remove all second-personal elements from his ethical theory. So it is not in spite of Kant’s view that morality arises from autonomy that we can account for duties towards non-moral beings, but because of it. This shows how a constructive, revisionist, radical approach can help us lay claim to ideas that are usually left to those opposed to stronger concern for animals.

Secondly, the project has shown that a constructive, revisionist, radical approach can also be interesting from an exegetical perspective. Not only does such an approach lead us to emphasise different questions than other contributions to the literature, but it often leads us to consider familiar questions from a different angle and make new connections. Case in point: The literature discusses the question to what extent the Formula of Humanity should be understood as a substantive moral principle (Reath 2013; see Chap. 4). But it was only during the search for Kantianism for Animals that this question turned out to have crucial implications for who matters morally. The further we remove the Categorical Imperative from direct action-guidance, the greater the prospect of including those who do not share the moral law. This also shows how exegetical issues are not always as morally innocent as they seem at first sight.

In other cases, what is primarily discussed as a problem or difficulty has turned out to be a positive resource for theory-modification. For instance, the literature discusses Thompson’s puzzle mostly as a difficulty for Kantian moral philosophers (Thompson 2004; Fanselow 2008; Darwall 2009; Palatnik 2018; see Chap. 5). In this debate, Kantians have something to lose—the plausibility of their ethical framework—and little to win. But in the present project, the puzzle has inspired the purely first-personal ‘content approach’ to moral directionality. So taking a constructive, revisionist, and radical approach can make visible a surprising creative potential.

Third, I hope that the book’s last part has illustrated what animal ethics has to gain from the modification and repurposing of ethical systems. By asking what it would take to include animals in moral consideration in a system that originally excluded them, we can gain new and unfamiliar perspectives on our moral relations to animals. I have highlighted that Kantianism for Animals can be used to criticise the practical-emotional stances towards animals inherent in our conduct. The framework condemns the stance from which we treat our own ends as overriding our duty to promote the happiness of animals, which leads to a novel, motive-oriented argument against animal use. It also offers novel possibilities because it combines concern for the happiness of others with concern for our own moral perfection, which can help account for the problematic nature of practices which do not directly harm animals. According to the argument I have proposed, eating meat violates a duty to self which we have only because we have duties towards animals. I have also highlighted that the framework has quite distinct upshots for environmental ethicists than other approaches. It enables a zoocentric critique of both anthropocentric and holistic environmentalism that can, at the very least, be an independent and interesting interlocutor position in environmental ethics.

Most fundamentally, however, repurposing Kant for animal ethics has produced a framework with an unfamiliar mission statement. Kantianism for Animals does not primarily aim at investigating what we ought to do, particularly in situations of moral conflict (an issue on which it is, like Kant, admittedly unclear). Kantianism for Animals instead aims to address the predicament of the ordinary moral agent—of feeling the pressure of duty yet being tempted to pursue inclination instead. It responds to this predicament with a positive account of what our duties demand and how they can demand it. It vindicates the duties we already take ourselves to be having most of the time and helps to safeguard us against the corrosive influence of self-serving rationalisations. This shows how reconsidering past philosophers can even reveal new practical purposes for animal ethics itself.

Turning back to Kantian animal ethics, the present project must leave some questions open. For one thing, the Kantian-for-Animals framework inherits some vaguenesses from Kant. Again, it does not give clear guidance on how to deal with moral conflicts, since Kant himself says lamentably little about this topic (Timmermann 2013, 36). So while Kantianism for Animals demands that we promote the happiness of others, it does not spell out what this means in cases where the happiness of one conflicts with the happiness of others. In such cases, there are two things we can do: First, we can take Kant’s silence as a reminder that moral philosophy can do other things besides resolving conflicts between putative duties (see Sect. 2.6); secondly, we can extend and modify the framework further. For instance, one could develop an account of moral conflict-resolution starting from Kant’s claim that duties cannot conflict, only their grounds (MM 6:224.17–21). While this book could only establish the bare bones of Kantianism for Animals, the framework is open to further specifications and modifications.

Admittedly, the project also makes a major omission that it does not inherit from Kant, since it does not cover duties of right (see Sect. 1.3). More work is needed to investigate what options are open to Kantian ethicists to account for legal protections for animals. If we take Kant’s philosophy as-is, it would appear that such protections are undermotivated, especially if they restrict the external freedom of human beings. But surely, the implication must strike many readers as morally repugnant, or indeed as absurd, that legal animal protections ought to be abolished out of respect for a putative freedom to abuse. What is more, the considerations in Chaps. 3 and 10 should caution us against exaggerated enthusiasm for ‘indirect duty’ views. Each time they have been offered, these positions turned out to be full of loopholes and exhibit considerable weaknesses. To secure a robust basis for legal animal protections in Kantianism, we must find some way to establish duties of right towards animals. Hence, there should be an interest on the part of both animal ethicists and Kantian ethicists to devote more attention to this topic.

Another limitation is that the present project proposed a system without doing much to defend it. On the one hand, there may be objections from moral intuition, according to which Kantianism for Animals has unacceptable implications. Seeking a reflective equilibrium between the Kantian framework and moral intuitions was never Kant’s goal, nor was it mine in this book. But to object to some of the framework’s upshots and then modify its claims to find an equilibrium can still be fruitful for theory-formation in animal ethics. Kantianism for Animals is not intended to be the final destination of moral theory. It is another ‘base camp’ from which to launch theoretical expeditions.

On the other hand, there may be theoretical objections from the perspective of other approaches. Though I have pointed out differences between Kantianism for Animals and utilitarianism and various views in animal and environmental ethics (Chaps. 7, 8, 9, and 10), I have not always provided an explanation why it is Kantianism for Animals that should strike us as more compelling. This kind of juxtaposition and comparative evaluation can be just as worthwhile as testing Kantianism for Animals against moral intuitions. The point of this book was to put Kantianism for Animals on the table in the first place.

Finally, it has become clear over the course of this book that there are many more issues on which a Kantian-for-Animals position can be developed. By discussing animal use, meat eating, and environmental protections, I have picked out three issues that are particularly prominent and important. But of course, I have left out many others. What might a Kantian-for-Animals say about animal euthanasia, wild animal suffering, moral education regarding animals, the ethics of captivity, or pet-keeping? I hope to have shown that Kantianism for Animals offers abundant resources to tackle such issues and that the views it produces are often original, stringent, and compelling.