Utilitarianism
John Stuart Mill · 1863
"The right action is whichever produces the greatest net happiness for the greatest number of people affected — an act is judged entirely by its consequences, not by the intentions behind it or any rule it follows."
Mill's utilitarianism, building on Bentham's earlier, cruder version, judges morality purely by outcomes: an action is right in proportion to how much aggregate happiness it produces and wrong in proportion to how much unhappiness it produces, with everyone's happiness counted equally regardless of who they are. Mill's key refinement over Bentham was insisting pleasures differ in quality, not just quantity — intellectual and moral pleasures rank higher than purely physical ones, famously summarized as it being better to be a human dissatisfied than a pig satisfied.
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Meditations
"Peace of mind comes from rigorously separating what's in your control — your judgments, intentions, reactions — from what isn't — external events, other people, outcomes, even your own body — and directing all effort at the former while accepting the latter without resistance."