One hypothetical creature could justify taking everything you own

Imagine a being that converts resources into happiness far more efficiently than anyone else — feeding it one meal generates more total joy than feeding a thousand ordinary people. If morality just means maximising total happiness, strict utilitarianism seems to say society should funnel everything to this 'utility monster' instead. Robert Nozick used the thought experiment to argue that pure utilitarianism ignores how resources are distributed between individuals.

— Robert Nozick, Anarchy, State, and Utopia — 1974
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