Begging the question

Bust of Aristotle, whose Prior Analytics contained an early discussion of this fallacy

Begging the question (or petitio principii) is a logical fallacy in which the proposition to be proved is assumed implicitly or explicitly in the premises. Begging the question is related to the fallacy known as circular argument, circulus in probando or circular reasoning. The first known definition in the West is by the Greek philosopher Aristotle around 350 BC, in his book Prior Analytics, where he classified it as a material fallacy.

History

The term was translated into English from the Latin in the 16th century. The Latin version, Petitio Principii (petitio: petition, request; principii, genitive of principium: beginning, basis, premise of an argument), literally means "a request for the beginning or premise." That is, the premise depends on the truth of the very matter in question.

The Latin phrase comes from the Greek en archei aiteisthai in Aristole's Prior Analytics II xvi:

"Begging or assuming the point at issue consists (to take the expression in its widest sense) in failing to demonstrate the required proposition. But there are several other ways in which this may happen; for example, if the argument has not taken syllogistic form at all, he may argue from premises which are less known or equally unknown, or he may establish the antecedent by means of its consequents; for demonstration proceeds from what is more certain and is prior. Now begging the question is none of these. [...] If, however, the relation of B to C is such that they are identical, or that they are clearly convertible, or that one applies to the other, then he is begging the point at issue.... [B]egging the question is proving what is not self-evident by means of itself...either because predicates which are identical belong to the same subject, or because the same predicate belongs to subjects which are identical."

Fowler's Deductive Logic (1887) argues that the Latin origin is more properly Petitio Quæsiti which is literally "begging the question".

Definition

Them: The Bible says that God exists. Me: But what makes you think that everything in the Bible is true? Them: Well, it's the word of God. Me: How do you know that? Them: It says so right here in the Bible.

There are two errors in the the title of this book by Robert M. Martin.

The fallacy of petitio principii, or "begging the question", is committed "when a proposition which requires proof is assumed without proof." More specifically, petitio principii refers to arguing for a conclusion that has already been assumed in the premise. The fallacy may be committed in various ways.

When the fallacy of begging the question is committed in a single step, it is sometimes called a hysteron proteron, as in the statement "Opium induces sleep because it has a soporific quality". Such fallacies may not be immediately obvious in English because the English language has so many synonyms; one way to beg the question is to make a statement first in concrete terms, then in abstract ones, or vice-versa. Another is to "bring forth a proposition expressed in words of Saxon origin, and give as a reason for it the very same proposition stated in words of Norman origin", as in this example: "To allow every man an unbounded freedom of speech must always be, on the whole advantageous to the State, for it is highly conducive to the interests of the community that each individual should enjoy a liberty perfectly unlimited of expressing his sentiments."

When the fallacy of begging the question is committed in more than one step, it is sometimes referred to as circulus in probando or reasoning in a circle.

"Begging the question" can also refer to making an argument in which the premise "is different from the conclusion ... but is controversial or questionable for the same reasons that typically might lead someone to question the conclusion."

Related Fallacies

Begging the question is related to the Fallacy of Circular Reasoning. The distinction between the two concepts is as follows: Circular Reasoning is the basing of two conclusions each upon the other (or possibly with more intermediate steps). That is, if you follow a chain of arguments and conclusions (a proof or series of proofs), one of the conclusions is presumed by an earlier conclusion. Begging the question can occur within one argument and consequent conclusion. In strict sense, Begging the question occurs if and only if the conclusion is implicitly or explicitly a component of an immediate premise. It is usually accepted, though, to use the term begging the question in place of circular argument.

Begging the question is also related to the Fallacy of many questions--a fallacy of technique that results from presenting evidence in support of a conclusion that is less likely to be accepted than merely asserting the conclusion.

A specific form of this is reducing an assertion to an instance of a more general assertion which is no more known to be true than the more specific assertion:

• All intentional acts of killing human beings are morally wrong.
• The death penalty is an intentional act of killing a human being.
• Therefore the death penalty is wrong.

If the first premise is accepted as an axiom within some moral system or code, this reasoning is a cogent argument against the death penalty. If not, it is in fact a weaker argument than a mere assertion that the death penalty is wrong, since the first premise is stronger than the conclusion.

Modern usage controversy

More recently, to beg the question has been used as a synonym for "to raise the question", or to indicate that "the question really ought to be addressed". For example, "This year's budget deficit is half a trillion dollars. This begs the question: how are we ever going to balance the budget?"

Using the term in this way, although common, is considered incorrect. but has nonetheless come into sufficiently widespread use. This usage is the result of confusion over the translation of petitio principii, which literally translates as "assuming the starting point." However, petitio also means begging; as a result, the phrase "'this begs the question' seems to mean that this begs us - asks us earnestly, entreats us - to raise and consider the question."

Arguments over whether such usage should be considered incorrect are an example of debate over linguistic prescription and description.

See also

• Ambiguity
• Fallacy of many questions
• Fallacies of definition
• Catch-22
• Circular definition
• Regress argument (diallelus)

References

• Cohen, Morris Raphael, Ernest Nagel, and John Corcoran. An Introduction to Logic. Hackett Publishing, 1993. ISBN 0872201449.
• Davies, Arthur Ernest. A Text-book of Logic. R.G. Adams and Company, 1915.
• Follett, Wilson. Modern American Usage: A Guide. Macmillan, 1966. ISBN 080900139X.
• Gibson, William Ralph Boyce, and Augusta Klein. The Problem of Logic. A. and C. Black, 1908.
• Kahane, Howard, and Nancy Cavender. Logic and contemporary rhetoric : the use of reason in everyday life. Cengage Learning, 2005. ISBN 0534626041.
• Kilpatrick, James. "Begging Question Assumes Proof of an Unproved Proposition." Rocky Mountain News (CO) 6 April 1997. Accessed through Access World News on 3 June 2009.
• Martin, Robert M. There are two errors in the the title of this book: a sourcebook of philosophical puzzles, problems, and paradoxes. New York: Broadview Press, 2002. ISBN 1551114933.
• Mercier, Charles Arthur. A New Logic. Open Court Publishing Company, 1912.
• Mill, John Stuart. A system of logic, ratiocinative and inductive: being a connected view of the principles of evidence, and the methods of scientific investigation. J.W. Parker, 1851.
• Safire, William. "On Language: Take my question please!." The New York Times 26 July 1998. Accessed 3 June 2009.
• Schiller, Ferdinand Canning Scott. Formal logic, a scientific and social problem. London: Macmillan, 1912.
• Welton, James. A Manual of Logic. W.B. Clive, 1905.