# Sound deductions can serve an unsound premise

Commentary on Orthodoxy by G. K. Chesterton.

On [CH03.P006](https://glosses.org/orthodoxy/pg16769-r1/CH03.P006/#char=166,265): "It was not meant to attack the authority of reason; rather it is the ultimate purpose to defend it."

The apparent reversal depends on a distinction between the ability to draw conclusions and the trustworthiness of the starting point. A useful comparator is Locke's account of madness in *An Essay Concerning Humane Understanding*, II.xi.13. Locke says that people suffering delusions may retain their inferential ability: they can "argue right from wrong Principles." Someone who imagines himself a king consequently demands royal treatment; someone who believes himself glass protects himself from breakage. Logical consistency does not establish that the premise is true. [Locke, II.xi.13, first-edition witness, printed p. 71](https://en.wikisource.org/wiki/Page:An_Essay_Concerning_Humane_Understanding_-_Locke_(1690).djvu/87).

The comparison also checks Chesterton's formulation. Locke explicitly assigns a role to violent imagination in forming these mistaken premises. He therefore supports the narrower distinction between correct inference and sound judgment, rather than Chesterton's comparative claim that reason is more dangerous than imagination. Read in that light, Chesterton's defence need not withdraw his criticism: reasoning can operate inside a delusion while the authority of reason remains something to preserve. The wider claim that the modern world threatens that authority is a further argument, not a result established by the example of madness.

The *Essay* first appeared in December 1689 with a 1690 title page; the linked witness is Wikisource's transcription of the London, Thomas Basset, 1690 edition, not a modern psychological account. This is a conceptual comparison, not evidence that Chesterton borrowed from Locke.

## Sources

- [John Locke, An Essay Concerning Humane Understanding (London: Thomas Basset, 1690), Wikisource transcription](https://en.wikisource.org/wiki/Page:An_Essay_Concerning_Humane_Understanding_-_Locke_(1690).djvu/87), Book II, chapter XI, section 13; printed p. 71; scan sequence 87
- [English Philosophical Texts Online: Locke, Essay II.xi](https://englishphilosophy.org/locke/ehu/2/11), Editorial copytext notice (1700 fourth edition) and section 13; notice supplies December 1689 publication date

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