This paper looks at the attribution of moral responsibility in the light of Kant's claim that the maxims of our actions should be universalizable. Assuming that it is often difficult for us to judge which actions satisfy this test, it suggests one way of translating Kantian morality into practice. Suppose that it is possible to read each action, via its maxim, as a communication addressed to the world: as an attempt to set the terms on which we should interact with one another. The paper suggests that respect for the actor requires us to take this communication seriously. When we suppose that an action is wrong, we then have a powerful reason to dispute its message: to hold the actor responsible for her deed. Although we are often unreliable judges ‘in our own case’, our mutual attributions of responsibility show us judging together, what the moral law should mean in practice.