Mark Timmons is Professor of Philosophy at the University of Arizona. He is the co-editor of Kant on Practical Justification: Interpretive Essays (OUP, 2013) and Reason, Value, and Respect: Kantian Themes from the Philosophy of Thomas E. Hill, Jr. (OUP, 2015) and author of Significance and System: Essays on Kant's Ethics (OUP, 2017), and Kant's Doctrine of Virtue (OUP, 2021).