What is at stake in the dispute between moral objectivism and subjectivism is how we are to give a rational grounding to ethical first principles or basic commitments. The search is for an explanation of what if anything makes any commitments good. Subjectivisms such as Blackburn's quasi-realism can give any set of commitments no ‘rational grounding’ in this sense except in considerations about internal consistency. But this is inadequate. Internal consistency is not sufficient for ethical rationality, since a set of obviously bad commitments could be internally consistent. Nor is it necessary, since a set of obviously good commitments could be internally inconsistent. I therefore argue for an objectivist view of the grounding of commitments, taking them to be attitudes which get their rationality, or lack of it, from their responsiveness to natural human needs and well-being. Since this view is objectivist, it avoids the problems which face subjectivism.