What type of reasoning does the author use? in the life boat eithics

Hardin's metaphor describes a lifeboat bearing 50 people, with room for ten more. The lifeboat is in an ocean surrounded by a hundred swimmers. The "ethics" of the situation stem from the dilemma of whether (and under what circumstances) swimmers should be taken aboard the lifeboat.

Hardin compared the lifeboat metaphor to the Spaceship Earth model of resource distribution, which he criticizes by asserting that a spaceship would be directed by a single leader - a captain - which the Earth lacks. Hardin asserts that the spaceship model leads to the tragedy of the commons. In contrast, the lifeboat metaphor presents individual lifeboats as rich nations and the swimmers as poor nations.