Certum est quia impossibile est

{{title-italics}}{{logicnav}}
'''''Certum est quia impossibile est''''' is [[Latin]] for "[This] is certain because [it] is impossible." Its origin is the early [[Christianity|Christian]] philosopher [[Tertullian]] (160-225 CE), where it appears in ''De Carne Christi'', Chapter 5:
<i>
:Crucifixus est dei filius; non pudet, quia pudendum est. 
:Et mortuus est dei filius; credibile prorsus est, quia ineptum est. 
:Et sepultus resurrexit; certum est, quia impossibile.</i>
 
:The [[Christ|Son of God]] was [[Crucifiction|crucified]]: I am not ashamed — because it is shameful. 
:The Son of God died: it is immediately credible — because it is silly.  
:[[Resurrection of Jesus|He was buried, and rose again]]: it is certain — because it is impossible.
: — Translation by Ernest Evans, 1956.

Often misquoted as ''credo quia absurdum'' (I believe because it is absurd), its meaning has long been seen as a rejection of 
[[reality]]
 [[rationalism]] in favor of [[faith]], a view dating back to at least Sir Thomas Browne (1605-1682 CE). However, ''De Paenitentia Chapter 1, verse 2'' shows Tertullian believed nothing of the kind.<ref> http://www.tertullian.org/quotes.htm </ref>

Instead, as John Moffatt observed in 1916,<ref>http://www.tertullian.org/articles/moffat_aristotle.htm </ref> ''certum est quia impossibile est'' is an argument in the tradition of reason (as it existed at the time of Tertullian) in the line of one of [[Aristotle]]'s forms as detailed in ''Rhetoric 2.23.21'':

:21. Another line of argument refers to things which are supposed to happen and yet seem incredible. We may argue that people could not have believed them, if they had not been true or nearly true: even that they are the more likely to be true because they are incredible. For the things which men believe are either facts or probabilities: if, therefore, a thing that is believed is improbable and even incredible, it must be true, since it is certainly not believed because it is at all probable or credible.
: — Translated by W. Rhys Roberts<ref>http://ebooks.adelaide.edu.au/a/aristotle/a8rh/book2.html </ref>

(It possibly should be added that this part of ''Rhetoric'' consists of a listing of all the kinds of argument Aristotle knew of, and thus probably more a descriptive than a proscriptive definition; [[Is–ought problem|that is, describing the form of the argument, but not saying anything more other than that "it is being used to attempt to persuade people and may possibly be valid in certain situations"]].)

Tertullian would thus seem to be using the reasoning of his time to argue in favor of the resurrection of [[Jesus Christ]] by arguing its merit based on the incredibility of it;<ref>http://www.tertullian.org/articles/sider_credo.htm</ref> however, given the greater aims of ''De Carne Christi'', exactly what Tertullian was trying to accomplish in these three lines is not certain.

Beyond that, the incredibility argument as detailed by Aristotle, used by Tertullian, and immortalized in this phrase, has since been abandoned as a reasonable argument. People's [[belief]]s, in and of themselves, are simply not a good indicator of the [[truth]] of any matter. History backs this analysis, as a great many improbable things people have been willing to believe have, in time, proven not to be true. Further, advances in human [[psychology]] and the understanding of how beliefs are formed have undercut Aristotle's basic reasoning in this case. (That being said, the inverse concept, that we should dismiss reports because they are "impossible", also known as [[argument from incredulity]], is not a very good argument itself; just to start with, we may be getting a distorted version of the truth, or one that only ''sounds'' impossible (e.g., the difference between "he lifted a twenty-ton weight" and doing that "with an industrial power-lifter").)

The argument may be paraphrased as, "Christianity is too weird to have been invented." Any who find that line of thinking convincing are advised to consider what it says about other faiths, such as [[Hinduism]] or [[Scientology]].

==See also==
*[[Argument from incredulity]]:  The exact opposite of this argument.
*[[Big Lie]]: Another famous usage of this argument.
==References==
{{reflist|2|90%}}
{{stub|logic}}
{{logfal}}

[[Category:Christianity]]
[[Category:Latin phrases]]
[[Category:Informal fallacies]]

Categories: Christianity, Latin phrases, Informal fallacies