The view that persons are entitled to respect because they are moral agents is fairly standard in modern day philosophy. What exactly is entailed by respecting persons as moral agents is, however, far less uncontroversial. In this dissertation, one particular aspect of respect for the moral agency of persons takes centre stage: the idea that if people do indeed matter because of their moral agency, then their moral judgments concerning issues by which they are directly affected (in particular those concerning the way they are treated by others) must matter as well. In fact, they matter so much that it is problematic to override or dismiss them, even when they can be shown to be fundamentally flawed, mistaken or otherwise in error ..