Principia Ethica
Principia Ethica (1903) by G.E. Moore is a cornerstone of analytic ethics, demanding precision about what “good” means and warning against the naturalistic fallacy.
Core Idea
Moore argues that “good” is a simple, unanalyzable property: any attempt to define it in natural terms (pleasure, desire, evolutionary fitness) commits the naturalistic fallacy. His “open question argument” tests this — for any proposed definition (“good = pleasant”), it remains an open, sensible question to ask “but is the pleasant actually good?”, showing the terms aren’t identical.
Why It Matters for Critical Thinking
A discipline of conceptual clarity: the open-question argument is a reusable tool for exposing smuggled definitions and demanding that key terms be pinned down before an argument can do any work.