Circular reasoning

A vicious circle, circle proof, logical circle, Diallele or hysteron proteron ( ancient Greek, literally the later before the ancients ), is a testament bug where the conditions contain the to be proved so. Thus, it is claimed to show a message through deduction by the message itself is used as a prerequisite. He is also called the vicious circle.

Here, a theory is derived in an argument by inference from premises whose validity is just as questionable as that of the thesis, even if they sound credible or give the impression to be independent of the acceptance of the theory valid. This represents a violation of the principle of sufficient reason dar. The self-reference can also be done in several stages, so that the circular reasoning careless observer, or even the author himself, remains hidden.

Circular arguments are only mistake a legitimate form of logical inference; the logical circle is the fifth of the five tropes of Agrippa and element of Münchhausen trilemma. If it is used in the eristic or Elenktik, so it is a special case of begging the question.

Examples

The Bible is God's Word, for it is written " all Scripture is inspired by God."

This argument cites the second letter to Timothy LUT from the New Testament; because the New Testament is a part of the Christian Bible, so the Bible's authority is established by a quotation from the Bible. The Bible thus draws its authority from the word of God itself Moreover, it is in the quote just an argumentum ad verecundiam because it comes from a specific letter of the Apostle Paul, that is a logically compelling rhetorical figure. Thus, one could indeed argue that reasoning is not self-referential: The canon of the Christian Bible did not exist when Paul wrote the second letter to Timothy. But therefore the author of the letter would probably have meant by " all Scripture " the Tanach.

Molière's doctors

Molière ridiculed in one of his comedies aptly this type of logical errors: The father of a mute daughter wants to know why his daughter is dumb. " Nothing is easier ," replied the doctor, " it depends on the lost power of speech. " "Of course, of course," replied the father, " but please tell me, for what reason she has lost the power of speech? " Then the doctor " All of our best writers tell us that which depends on the inability to speak the language. "

Self confirmatory witness

" For example, if a court finds a witness was credible, but refers only to the testimony of the witness himself to its credibility, it just goes, there is at least the suspicion that was here before the verdict about the credibility of the witness. before his statement was further considered " ( Joerden: logic in the law)