Two Revolutions in the Philosophy of Norms In the twentieth century two revolutionary turns were accomplished in the philosophical research on norms and normativity: The first was the creation of a full-fledged deontic logic, a decade-long development which went through stages1 before it culminated in the publication of the essay “Deontic Logic” by Georg Henrik von Wright in 1951. The second was the conceiving of the idea of a constitutive rule
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