Martha Nussbaum has claimed that it is possible for a moral agent to be confronted, through no fault of his own, with an irresolvable conflict between his moral duties; and cites Kant as someone who takes the opposing view. Kant did indeed take the view that conflict between duties was inconceivable, but Nussbaum has failed to grasp his main reason for doing so, namely the principle that ‘ought’ implies ‘can’. When that principle is properly understood it can be seen that a Kantian account, or one drawing upon Kantian resources, can make more sense of our being confronted, seemingly, by incompatible duties than the account Nussbaum herself offers.