Idem per idem

Idem per idem ( Latin for "the same thing by the same") is the Latin name for the logical error that is that in the definition of a concept that even in definable expression (Definiens) occurs. Some authors use idem per idem synonymously with tautology when the definition is identical . The word meaning of both expressions is also identical: Latin idem = ancient Greek τό αυτό = German the same .

If a concept is not determined by itself, but a sentence is proven by itself, the error is not idem per idem , but a circular argument . Both are special cases of the Petitio Principii .

Concept history

Karl Christian Friedrich Krause formulates the first "Basic Law of Definition":

“The first requirement is: what is to be defined must not appear again in the definition (terminus definitus non debet ingredi definitionem) , because if this were, one would not find out what that is to be defined, the same would be explained by the same, idem per idem, as they say. "

Krause provides two examples:

“For example, the term: reason should be defined , since one usually says: the reason of something is that by which this something is. But you don't get to know anything because it is defined idem per idem ; one has only inserted another word instead of reason , i.e. i. the word: by , which is synonymous with reason , or when one should define the space, and one says: the space is the form according to which the physical is next to and with each other, here is explained idem per idem ; because you then understand the word: next to , spatially. "

Friedrich Ueberweg distinguishes the error idem per idem “where the term to be defined either expressly or veiled in the definition” from the diallele (circulus sive orbis in definiendo), “where A through B and B through A, or A through B, B by C, C by D etc. and D or any subsequent term is again defined by A […] ”.

Heinrich Schmidt does not use idem per idem , but uses a different definition of dialleles : "... [1] Circular conclusion, ... [2] also any declaration that includes what is to be explained [...] in the declaration. "(circle definition, see above)

literature

GS Ogden: Idem Per Idem: Its Use and Meaning. In: Journal for the Study of the Old Testament. Volume 17, No. 53, 1992, pp. 107-120.
Marek Piela: Four topics in modern Hebrew grammar. In: Studia Linguistica Universitatis Iagellonicae Cracoviensis. Volume 125, 2008, pp. 121-132 ( full text on academia.edu).

swell

↑ Eg Rudolf Eisler : Dictionary of Philosophical Terms. 2nd edition Berlin 1904: "Tautology [...] or errors of the idem per idem , ie the circle definition [...]" (vol. 2, p. 484).
↑ Also Heinrich Schmidt (.... Philosophical Dictionary merits v Heinrich Schmidt 14th edition, revised and supplemented ed u v Georgi Schischkoff Stuttgart 1957......) Noted: "tautology is also the circular definition" (p 589) which he defines (under diallels ) as "any definition that includes what is to be explained in the explanation in an open or hidden way" (p. 111).
↑ ^a ^b Karl Christian Friedrich Krause: The doctrine of knowledge and knowledge, as the first introduction to science. Lecture for educated people from all backgrounds. Dietrich'sche Buchhandlung, Göttingen 1836, p. 502.
↑ Friedrich Ueberweg: System of logic and history of logical teachings. 2nd Edition. Adolph Marcus, Bonn 1865, p. 128.
^ Heinrich Schmidt: Philosophical dictionary. Justified v. Heinrich Schmidt. 14th edition, reviewed a. adds u. ed. v. Georgi Schischkoff. Stuttgart 1957., p. 111.

[1] Eg Rudolf Eisler : Dictionary of Philosophical Terms. 2nd edition Berlin 1904: "Tautology [...] or errors of the idem per idem , ie the circle definition [...]" (vol. 2, p. 484).

[2] Also Heinrich Schmidt (.... Philosophical Dictionary merits v Heinrich Schmidt 14th edition, revised and supplemented ed u v Georgi Schischkoff Stuttgart 1957......) Noted: "tautology is also the circular definition" (p 589) which he defines (under diallels ) as "any definition that includes what is to be explained in the explanation in an open or hidden way" (p. 111).

[Krause-1836-502-3] Karl Christian Friedrich Krause: The doctrine of knowledge and knowledge, as the first introduction to science. Lecture for educated people from all backgrounds. Dietrich'sche Buchhandlung, Göttingen 1836, p. 502.

[4] Friedrich Ueberweg: System of logic and history of logical teachings. 2nd Edition. Adolph Marcus, Bonn 1865, p. 128.

[5] Heinrich Schmidt: Philosophical dictionary. Justified v. Heinrich Schmidt. 14th edition, reviewed a. adds u. ed. v. Georgi Schischkoff. Stuttgart 1957., p. 111.