This paper traces the evolution of Philippa Foot's way of thinking about moral issues, going beyond her particular opinions and philosophical positions to examine her methodology. Guided by a continuous struggle against the limits of what moral philosophy sees as a legitimate statement, her work is much more coherent than the author herself seems to have thought. Philippa Foot looked for a natural raison d'être to morality-one that would ensure its reality-without always being sure what "natural" means. Her work evolved around this theme across three distinct periods. To begin, she was simply a realist. Then, she drew close to David Hume and his refusal to give a definitive and universal foundation for morality. Finally, she ended her philosophical work by adopting Neo-Aristotelianism. Her contribution to moral philosophy was twofold. Her first philosophical stances were made in dialogue with expressivism to advance a metaethics. She later moved on to practical ethics, or rather a general reflection on the variety of normativities engaged in difficult life decisions. While sympathetic to this struggle, the present text will not simply follow all the choices made by Foot. It may indeed be the case that contemporary moral philosophy cannot, and should not, propose such wide-ranging conceptions. Working on the grammar of morality means working on its conceptual errors, its flawed definitions, and its unacknowledged presuppositions rather than providing a general anthropology, which requires a different methodology. Moral philosophy as grammar should probably concentrate the critical work. The practical consequence of this effort leads to elucidating the decisions made on a case-by-case basis as much as possible.