Korsgaard is an advocate of
animal rights. She was a
vegetarian for over 40 years and is now a
vegan. In 2018, Korsgaard authored
Fellow Creatures: Our Obligations to Other Animals which argues that
Kantian ethics supports animal rights. She has also given several lectures about animal rights, including the 2014 Uehiro Lectures on The Moral and Legal Standing of Animals. In these lectures, Korsgaard argues that importance is tethered to a creature who finds it important. While according to this view there is no "free-floating" untethered importance, there is absolute importance, which occurs when something is important to all beings. Therefore, to Korsgaard, the statement that animals are universally less important than humans is not incorrect, but incoherent. She distinguishes between the evaluative or functional
good, where something is good because it is able to perform its function well, and the final good, where an end or a life is good. Final goods are what make things important, and a thing possesses the final good if things can be good or bad for that thing. She also distinguishes between ordinary objects such as knives, for which being sharpened is good in the sense that it helps the knife achieve its function of cutting well, organisms, which have a function to tend to their and their species' own well-functioning, and animals, a particular kind of organism which represent the world to themselves and act using this representation for the function of self-maintenance. This representation enables the animal to have self-maintenance not only as a functional good, but also as a final good. Therefore, final goods need not come from
people, but from any animal. Korsgaard defines people as "normative self-governed beings" and says that the rational capacity to evaluate oneself and reflect on one's motives makes people different from animals. This means that while non-person animals are not responsible for their actions and do not have duties to other animals, people are and do. Further, she distinguishes between two different kinds of ends-in-of-themselves: • Something is an end-in-of-itself in the
active sense if it is capable of legislating ends that one must respect. • Something is an end-in-of-itself in the
passive sense if things that are good for it are good absolutely. Clearly the active sense implies the passive sense, but Korsgaard departs from Kant in claiming that the converse fails. In fact, the choice to set a value on an end is made merely because one desires the end, because it is good with respect to the being making the choice; in other words, because it is a being with the final good. Therefore, when universalized using the
formula of universal law, the being is committed to valuing the ends of all beings with the final good (animals). In other words, all animals are passive ends-in-of-themselves, but non-person are not active ends-in-of-themselves. ==Selected publications==