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Cover of Principia Ethica

Principia Ethica

Written by G. E. (George Edward) Moore

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Ethics

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About this book

"Principia Ethica" by G. E. Moore is a philosophical treatise written in the early 20th century. The work delves into the foundational questions of ethics, particularly focusing on the nature of good and the principles of ethical reasoning. It seeks to clarify essential ethical concepts and questions, distinguishing between what ought to exist for its own sake and what actions ought to be performed. At the start of "Principia Ethica," Moore establishes the premise that ethical confusion often arises from a lack of clarity about the questions being posed, arguing for the necessity of understanding what is meant by 'good' before attempting to define it. He distinguishes between two primary kinds of questions in ethics: those related to the intrinsic goodness of things and those concerning the rightness of actions. Moore contends that ethical propositions regarding what exists for its own sake are indefinable and presents the so-called 'naturalistic fallacy,' which critiques the conflation of moral terms with natural properties. He emphasizes the importance of this distinction as a foundation for serious ethical inquiry.

Reading guide

Themes, characters and key ideas in Principia Ethica, written by Chaptra AI.

  • about 12 hours
  • advanced
  • analytical
  • rigorous
  • foundational

G. E. Moore's "Principia Ethica" is a seminal work of early 20th-century analytical philosophy that fundamentally reshaped meta-ethics. Moore argues that the central concept of 'good' is simple, unanalyzable, and indefinable, akin to the color yellow. He introduces the influential 'naturalistic fallacy,' critiquing attempts to define 'good' in terms of natural properties (like 'pleasant' or 'desired') or metaphysical properties, asserting that such definitions confuse the property itself with something that merely possesses it. The book meticulously distinguishes between questions of intrinsic value (what is good for its own sake) and questions of conduct (what actions are right), laying the groundwork for a rigorous, non-naturalistic approach to ethical inquiry. Ultimately, Moore concludes that the highest intrinsic goods are personal affection and aesthetic enjoyment, offering a positive ethical vision grounded in his meta-ethical foundations.

“If I am asked 'What is good?', my answer is that good is good, and that is the end of the matter. Or if I am asked 'How is good to be defined?', my answer is that it cannot be defined, and that is all I have to say about it.”

Key themes

The Indefinability of 'Good'
Moore's central thesis is that 'good' is a simple, unanalyzable, non-natural property that cannot be defined in terms of any other concept. He argues that any attempt to define 'good' reduces it to something else, missing its unique moral quality. This is supported by his 'open-question argument,' which posits that for any proposed definition X of 'good,' it always remains an open and meaningful question whether 'Is X good?'
The Naturalistic Fallacy
This is the most famous concept introduced by Moore. The naturalistic fallacy is the error of attempting to define the non-natural property 'good' in terms of some natural property (e.g., pleasure, desire, happiness, evolutionary fitness) or a metaphysical property. Moore argues that such definitions confuse the property 'good' itself with something that merely *has* that property, thereby failing to grasp the unique meaning of 'good'.
Intrinsic vs. Instrumental Value
Moore meticulously distinguishes between things that are good in themselves (intrinsic goods) and things that are good only as a means to achieve something else (instrumental goods). He argues that the primary task of ethics is to identify intrinsic goods, as all instrumental goods derive their value from their ability to promote these ultimate goods.

Worth discussing

Is 'good' truly indefinable, as Moore argues, or can it be defined in naturalistic terms without committing a fallacy?

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