A prosleptic syllogism (; from
Greek
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Greece
Anything of, from, or related to Greece, a country in Southern Europe:
*Greeks, an ethnic group.
*Greek language, a branch of the Indo-European language family.
**Proto-Greek language, the assumed last common ancestor ...
πρόσληψις ''proslepsis'' "taking in addition") is a class of
syllogism
A syllogism ( grc-gre, συλλογισμός, ''syllogismos'', 'conclusion, inference') is a kind of logical argument that applies deductive reasoning to arrive at a conclusion based on two propositions that are asserted or assumed to be true ...
s that use a prosleptic proposition as one of the premises.
The term originated with
Theophrastus
Theophrastus (; grc-gre, Θεόφραστος ; c. 371c. 287 BC), a Greek philosopher and the successor to Aristotle in the Peripatetic school. He was a native of Eresos in Lesbos.Gavin Hardy and Laurence Totelin, ''Ancient Botany'', Routle ...
.
"History of Logic: Theophrastus of Eresus"
in Encyclopædia Britannica Online
An encyclopedia (American English) or encyclopædia (British English) is a reference work or compendium providing summaries of knowledge either general or special to a particular field or discipline. Encyclopedias are divided into article ...
.
Figures
Prosleptic syllogisms are classified in three figures, or potential arrangements of the terms according to the figure of the prosleptic proposition used.
* First figure: "A is universally predicated of everything that is universally predicated of G"
* Second figure: "Everything predicated universally of A is predicated universally of G"
* Third figure: "A is universally predicated of everything of which G is universally predicated"
Consequently, a third figure prosleptic syllogism would read "A is universally affirmed of everything of which G is universally affirmed; G is universally affirmed of B; therefore, A is universally affirmed of B." ("All G are A; all B are G; therefore, all B are A" or "Statement A is always true of everything for which statement G is always true; statement G is true of all things B; therefore, statement A is true of all things B.")
Notes
References
* William & Martha Kneale
''Prosleptic Propositions and Arguments''
in M. S. Stern, Albert Hourani, Vivian Brown (eds.), ''Islamic Philosophy and the Classical Tradition'', London: Bruno Cassireer, 1972, pp. 189-207.
Arguments
Term logic
Syllogism
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