---
title: "Is-Ought Problem (Hume's Guillotine) Explained"
description: "The is-ought problem says facts alone cannot prove values; Hume's Guillotine blocks deriving an \"ought\" from an \"is.\" Key for UPSC GS4 ethics and metaethics."
url: "https://modeldiplomat.com/learn/glossary/is-ought-problem"
---

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Model Diplomat Research Team · Last reviewed June 22, 2026

TL;DR

- The is-ought problem holds that no purely descriptive premise about what is can logically entail a prescriptive conclusion about what ought to be.
- What is the difference between the is-ought problem and the naturalistic fallacy?
- Did Hume coin the phrase 'Hume's Guillotine'?
- Has anyone successfully derived an 'ought' from an 'is'?
- Why does the is-ought problem matter for ethics case studies in UPSC GS4?

[Civil Service & Diplomatic Exams](https://modeldiplomat.com/learn/civil-services/glossary)Updated June 22, 2026

The is-ought problem holds that no purely descriptive premise about what is can logically entail a prescriptive conclusion about what ought to be.

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