Begging the Question is a fallacy that occurs when the conclusion of an argument is contained in the premises used to support it. Hence, the argument is said to beg the question it purports to prove. Alternatively, it may be said to go in circles. As the result of this pattern is an argument in which support for the conclusion assumes its own truth, it effectively provides no substantive basis upon which to accept the truth of the conclusion.
In most cases, the premise will be sufficient from that of the conclusion to make recognition difficult for those engaged in the conversation to recognize it. In others, the argument may be sufficiently complex that a speaker fails to notice (or hopes their audience won’t notice) they have stuck their conclusion back into the premises of the argument. In still others, the truth of the conclusion is assumed tacitly by other premises within the argument. Either way, it often takes some reflection to see that the conclusion matches one of the premises of the argument in question.
Take for example the following arguments:
“I know god exists, because the Bible tells me so, and I know the Bible is correct, because it is the word of God.”
“God does not exist. That’s just a myth!”
In the first case, the notion that Bible is the word of god assumes that God exists, so the conclusion of the argument is assumed by the premise offered in support of his existence. Hence, the argument is circular in virtue of an implied premise that matches the conclusion.
In the second, the notion that God is just a myth assumes that he is not real in the first place, so an argument dismissing belief in God on this basis assumes that he is not real to begin with. So, if the second statement is understood to be a reason for believing the first, the result is a circular argument.
Circular argumentation (or begging the question) is an incredibly common fallacy. The problems with this fallacy are actually rather central to the nature of logic and reasoning itself, particularly insofar as they illustrate the practical significance of providing a reason to believe something in the first place.
Oddly Interactive Problem: As noted above, what makes a circular argument a fallacy is the failure to provide any reasons to believe the conclusion which are not dependent on the conclusion itself. As some have noted, (Perelman and Olbrechts-Tyteca, for example pp. 112-114), this not strictly speaking a failure of logic. It is a failure of rhetoric. By some logical tests (e.g. truth tables), a circular argument seems to pass with flying colors. So, why isn’t it valid? Some would actually say that it is valid, though still fallacious. Others might just say it is invalid. Either way, the problem is the argument produces no new reason to believe its conclusion, hence the argument fails to accomplish what people normally use arguments for; it fails as a means of persuasion. It is as much a failure of social interaction as it is a failure of reasoning.
“Begs the question“: In discussing a belief or claim, one might hear someone say; “this begs the question of…” Of course this is roughly equivalent to suggest that the matter “raises the question of…” This bothers some people to no end, because a raising a question is not the same as committing the logical fallacy of begging the question. On the other hand, the usage often carries some implication that a specific answer to the question they wish to raise has already been assumed by those advocating the belief or claim which triggered their comment. This isn’t quite equivalent to the fallacy of begging the question, but it does bear a certain family resemblance, so to speak. The usage does not, strictly speaking, match common logical definitions of the fallacy, but isn’t entirely devoid of sense. In any event, language usage varies.
Circularity of Reasoning: There is an interesting problem in epistemology insofar as we can find a degree of reasoning in many theories, perhaps even most. …possible all of them? Likewise if you examine people’s world views in general, you will likely find a degree of circularity in the relationship between their basic premises about how the world works and what it means to know something and the particular conclusions they draw about the world around them. What separates the circularity of reasoning on such a grand scale and that of a circular argument is the scope of the subject matter. Whether or not that is sufficient to resolve any of the problems in question is another question, but one does sometimes hear people talk about whether or not a given instance of circular reasoning is vicious. Presumably, a ‘yes’ answer means trouble, A ‘no’ gets you a pass. Whether or not the distinction can be made on the basis of a non-circular argument is another question, as is any question about whether or not the circularity of the distinction would itself be vicious.
Reflexivity can be a real bitch!
Synonyms: I have seen some folks distinguish begging the question from circular argumentation. The wikipedia entries in question currently do so emphasizing the notion that a circular argument begins with the conclusion it purports to prove whereas the entry on begging the question merely suggests the conclusion is assumed in the premises. there is certainly room to draw a significant distinction there, but the usage is not standardized. In practice, most people seem to use these terms interchangeably.
Tautology: Circular argumentation shares a lot in common with tautology, enough so that the two are often confused with one another. A tautology may be described as an assertion that is true by every possible variation of the truth value of its components. If I say, “It is safe to go outside, unless it is not,” that statement is true for all possible truth values, because its individual components are contradictory. One will always be true and one will always be false. So, my statement to the effect that one or the other is true will always be true, regardless of the facts. By way of contrast, If I say, “Either Bob has my Pen or Bill has it,” then if neither of them has it, my statement is false. This is the way most assertions work. Falsehood is at least possible. A tautology is true regardless of the particulars. Another way of putting it would be to say that it is true by virtue of its logical form (e.g. A or not A). The problem with tautologies is that they don’t tell us much about the real world, so to speak. They might be used on occasion to help us organize information, but they do not commit a speaker to any specific account of the facts.
I have seen the difference between a tautology and a circular argument explained in a few different ways, but the most clear explanation that I am aware of is to think of a tautology as a feature of a single statement whereas a circular argument is a feature of an argument.