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

Begging the question (or petitio principii, "assuming the initial point") is a logical fallacy in which the proposition to be proved is assumed implicitly or explicitly in the premise. Begging the question is related to circular argument, circulus in probando (Latin for "circle in proving") or circular reasoning but they are considered absolutely different by Aristotle.^[1] The first known definition in the West is by the Greek philosopher Aristotle around 350 BCE, in his book Prior Analytics, where he classified it as a material fallacy.

[edit] 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) [of] 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.

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

[edit] Definition

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The fallacy of petitio principii, or "begging the question", is committed "when a proposition which requires proof is assumed without proof."^[2] 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,^[3] as in the statement "Opium induces sleep because it has a soporific quality".^[4] 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.^[4] 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",^[5] 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."^[6]

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^[3] but incorrectly so, if we look at the definition Aristotle gave in Prior Analytics.^[1]

"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."^[7]

.... seldom is anyone going to simply place the conclusion word-for-word into the premises .... Rather, an arguer might use phraseology that conceals the fact that the conclusion is masquerading as a premise. The conclusion is rephrased to look different and is then placed in the premises.

—Paul Herrick, ^[8]

[edit] Related fallacies

In informal situations, the term begging the question is often used in place of circular argument. In the formal context however, begging the question holds a different meaning.^[1] In its shortest form, circular reasoning is the basing of two conclusions by means of which there is demonstrated a reversed premise of the first argument. Begging the question does not require any such reversal.

Begging the question is similar 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, rather 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.

[edit] Modern usage

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. This usage is commonly followed by a colon^{[citation needed]} and the statement of the question. 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 by prescriptive grammarians.^[9] This usage is the result of confusion over the translation of petitio principii, which literally translates as "assuming the starting point".^[10]

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

[edit] See also

[edit] Notes

[edit] References