Kantianism
Kantianism is the philosophy of Immanuel Kant, a German philosopher born in Königsberg, Prussia (now Kaliningrad, Russia). The term "Kantianism" or "Kantian" is sometimes also used to describe contemporary positions in philosophy of mind, epistemology, and ethics.
Kantian ethics
Philosopher Onora O'Neill, who studied under John Rawls at ￼Harvard University, is a contemporary Kantian ethicist who supports a Kantian approach to issues of social justice. O'Neill argues that a successful Kantian account of social justice must not rely on any unwarranted idealizations or assumption. She notes that philosophers have previously charged Kant with idealizing humans as autonomous beings, without any social context or life goals, though maintains that Kant's ethics can be read without such an idealization. O'Neill prefers Kant's conception of reason as practical and available to be used by humans, rather than as principles attached to every human being. Conceiving of reason as a tool to make decisions with means that the only thing able to restrain the principles we adopt is that they could be adopted by all. If we cannot will that everyone adopts a certain principle, then we cannot give them reasons to adopt it. To use reason, and to reason with other people, we must reject those principles that cannot be universally adopted. In this way, O'Neill reached Kant's formulation of universalisability without adopting an idealistic view of human autonomy. This model of universalisability does not require that we adopt all universalisable principles, but merely prohibits us from adopting those that are not.