Diogenes Laërtius · fl. 3rd century CE
Lives of Eminent Philosophers 7.78 — Diogenes Laërtius on the Stoics
Translation by R. D. Hicks (1925)
Diogenes Laërtius, Lives of Eminent Philosophers 7.78
Reported speech · Diogenes Laërtius on the Stoics
Of conclusive some are denoted by the common name of the whole class, “conclusive proper,” others are called syllogistic. The syllogistic are such as either do not admit of, or are reducible to such as do not admit of, immediate proof in respect of one or more of the premisses; e.g. “If Dion walks, then Dion is in motion; but Dion is walking, therefore Dion is in motion.” Conclusive specifically are those which draw conclusions, but not by syllogism; e.g. the statement “It is both day and night” is false: “now it is day; therefore it is not night.” Arguments not syllogistic are those which plausibly resemble syllogistic arguments, but are not cogent proof; e.g. “If Dion is a horse, he is an animal; but Dion is not a horse, therefore he is not an animal.”
Cite this passage
Diogenes Laërtius, Lives of Eminent Philosophers 7.78 (on the Stoics), tr. R. D. Hicks (1925)
https://whatwouldstoicsdo.com/passage/lives-of-the-stoics/7.78
Diogenes Laërtius, Lives of Eminent Philosophers, Book VII, tr. R. D. Hicks (Loeb, 1925). Text: Perseus Digital Library (CC BY-SA 4.0). Sources and licences
In plain English
AI-written notesSorts conclusive arguments into syllogistic and merely conclusive types, and gives an example of a faulty argument that only looks like a syllogism, concluding that Dion is not an animal because he is not a horse. Logic terminology.
Older wording
- “syllogistic”
- — in the form of a syllogism, a standard valid argument
- “cogent”
- — convincing, logically strong
- “conclusive proper”
- — arguments that prove a conclusion but not by a standard syllogism
Themes and situations
- Judgements and impressions
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