In classical rhetoric and logic, begging the question or assuming the conclusion (Latin: ) is an informal fallacy that occurs when an argument's premises assume the truth of the conclusion. Historically, begging the question refers to a fault in a dialectical argument in which the speaker assumes some premise that has not been demonstrated to be true. In modern usage it has come to refer to an argument in which the premises assume the conclusion without supporting it. This makes it more or less synonymous with circular reasoning.
Some examples are:
People have known for thousands of years that the earth is round. Therefore, the earth is round.
Coca Cola is the most popular soft drink in the world. Therefore, no other soft drink is as popular as Coca Cola.
God possesses all the virtues. Benevolence is a virtue. Therefore, God is benevolent.
The phrase "begs the question" is also commonly used in an entirely unrelated way to mean "prompts a question" or "raises a question".
History
The original phrase used by Aristotle from which begging the question descends is , or sometimes , . Aristotle's intended meaning is closely tied to the type of dialectical argument he discusses in his Topics, book VIII: a formalized debate in which the defending party asserts a thesis that the attacking party must attempt to refute by asking yes-or-no questions and deducing some inconsistency between the responses and the original thesis.
In this stylized form of debate, the proposition that the answerer undertakes to defend is called () and one of the rules of the debate is that the questioner cannot simply ask for it (that would be trivial and uninteresting). Aristotle discusses this in Sophistical Refutations and in Prior Analytics book II, (64b, 34–65a 9, for circular reasoning see 57b, 18–59b, 1).
The stylized dialectical exchanges Aristotle discusses in the Topics included rules for scoring the debate, and one important issue was precisely the matter of asking for the initial thing—which included not just making the actual thesis adopted by the answerer into a question, but also making a question out of a sentence that was too close to that thesis (for example, PA II 16).
The term was translated into English from Latin in the 16th century. The Latin version, , can be interpreted in different ways. (from ), in the post-classical context in which the phrase arose, means or , but in the older classical sense means , or . , genitive of , means , or (of an argument). Literally means or .
The Latin phrase comes from the Greek ( ) in Aristotle's Prior Analytics II xvi 64b28–65a26:
Aristotle's distinction between apodictic science and other forms of nondemonstrative knowledge rests on an epistemology and metaphysics wherein appropriate first principles become apparent to the trained dialectician:
Thomas Fowler believed that would be more properly called , which is literally .
Definition
To (also called ) is to attempt to support a claim with a premise that itself restates or presupposes the claim. It is an attempt to prove a proposition while simultaneously taking the proposition for granted.
When the fallacy involves only a single variable, it is sometimes called a hysteron proteron (Greek for ), a rhetorical device, as in the statement:
Reading this sentence, the only thing one can learn is a new word in a more classical style (soporific), for referring to a more common action (induces sleep), but it does not explain why it causes that effect. A sentence attempting to explain why opium induces sleep, or the same, why opium has soporific quality, would be the following one:
A less obvious example from Fallacies and Pitfalls of Language: The Language Trap by S. Morris Engel:
This form of the fallacy may not be immediately obvious. Linguistic variations in syntax, sentence structure, and the literary device may conceal it, as may other factors involved in an argument's delivery. It may take the form of an unstated premise which is essential but not identical to the conclusion, or is "controversial or questionable for the same reasons that typically might lead someone to question the conclusion":
For example, one can obscure the fallacy by first making a statement in concrete terms, then attempting to pass off an identical statement, delivered in abstract terms, as evidence for the original. One could also "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 here:
When the fallacy of begging the question is committed in more than one step, some authors dub it , or more commonly, circular reasoning.