''Ignotum per ignotius'' (

Latin Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...

for "the unknown by the more unknown") describes an explanation that is less familiar than the concept it would explain. An example would be: "The oven felt hot because of

Fourier's Law Conduction is the process by which heat is transferred from the hotter end to the colder end of an object. The ability of the object to conduct heat is known as its ''thermal conductivity'', and is denoted . Heat spontaneously flows along a tem ...

." It is unlikely that a person unfamiliar with the hotness of ovens would be enlightened by a reference to a fundamental law of physics. Another example would be referencing

Rayleigh scattering Rayleigh scattering ( ), named after the 19th-century British physicist Lord Rayleigh (John William Strutt), is the predominantly elastic scattering of light or other electromagnetic radiation by particles much smaller than the wavelength of the ...

as an explanation for why the sky is blue, when a more apt explanation would be simply that air is blue. That said, since these explanations could enlighten people in theory, ''ignotum per ignotius'' is not strictly a logical fallacy; it is just a criticism of an argument on rhetorical grounds, stating that such an argument is not useful in a particular context.

''Ignotum per æque ignotum''

''Ignotum per æque ignotum'', meaning "the unknown by the equally unknown", is a related form of

fallacy A fallacy is the use of invalid or otherwise faulty reasoning, or "wrong moves," in the construction of an argument which may appear stronger than it really is if the fallacy is not spotted. The term in the Western intellectual tradition was intr ...

in which one attempts to prove something unknown by deducing it from something else that is also not known to be true.

Galileo Galileo di Vincenzo Bonaiuti de' Galilei (15 February 1564 – 8 January 1642) was an Italian astronomer, physicist and engineer, sometimes described as a polymath. Commonly referred to as Galileo, his name was pronounced (, ). He was ...

, ''

Dialogue Concerning the Two Chief World Systems The ''Dialogue Concerning the Two Chief World Systems'' (''Dialogo sopra i due massimi sistemi del mondo'') is a 1632 Italian-language book by Galileo Galilei comparing the Copernican system with the traditional Ptolemaic system. It was transl ...

'', Day 2.

References

{{DEFAULTSORT:Ignotum Per Ignotius Latin logical phrases Ignorance

''Ignotum per æque ignotum''

See also

References