Why does the author of Lifeboat Ethics choose to begin his essay with this lifeboat metaphor?

The author of "Lifeboat Ethics" begins with the lifeboat metaphor to illustrate the challenges of resource distribution and moral responsibility in a world with limited resources. This metaphor effectively conveys the precarious situation of wealthy nations versus impoverished ones, emphasizing the ethical dilemmas involved in aiding those in need while considering the sustainability of resources. By framing the discussion in this way, the author aims to provoke critical thinking about the implications of generosity and the potential consequences of overextending aid.