Challenging a renowned Harvard professor's take on human morality. Christine Korsgaard teaches philosophy at Harvard. She strongly believes that Immanuel Kant's idea that we should act "in ways that respect the preferences and projects of others" could be extended to our relationship with animals, thus resulting in a significant behavioural change. For Peter Godfrey-Smith, however, that's a failed argument. In this piece, the University of Sydney professor explains why.