[I]f I am walking past a shallow pond and see a child drowning in it, I ought to wade in and pull the child out. This will mean getting my clothes muddy, but this is insignificant, while the death of the child would presumably be a very bad thing…It makes no moral difference whether the person I can help is a neighbor's child ten yards from me or a Bengali whose name I shall never know, ten thousand miles away.
Peter Singer, "Famine, Affluence, and Morality" (1972)
Injustice anywhere is a threat to justice everywhere. We are caught in an inescapable network of mutuality, tied in a single garment of destiny. Whatever affects one directly affects all indirectly.
Martin Luther King, Jr., "Letter from Birmingham Jail" (1963)
This is a world of compensations…Those who deny freedom to others, deserve it not for themselves; and, under a just God, can not long retain it.
Abraham Lincoln, letter to Henry Pierce and others (1859)
Nothing but such general evils as threaten the whole community can disturb the tranquil sleep of the philosopher, or tear him from his bed. A murder may with impunity be committed under his window; he has only to put his hands to his ears and argue a little with himself, to prevent nature, which is shocked within him, from identifying itself with the unfortunate sufferer.
Jean-Jacques Rousseau, Discourse on the Origin and Basis of Inequality Among Men (1755)