LOGIC l "Begging the Question" l John J. Parsons l Bible Teaching University l NIGHT SCHOOL

Begging the Question

Also Known as: Circular Reasoning, Reasoning in a Circle, Petitio Principii. Begging the Question is a fallacy in which the premises include the claim that the conclusion is true or assume that the conclusion is true. That is, the truth of the conclusion is assumed by the premises. Note that in most cases some sort of phraseology is employed that conceals the fact that the premise is merely a restatement of the conclusion (and the conclusion is therefore used to support the premise of the argument!).   Example: Capital punishment is justified for the crimes of murder and kidnapping because it is quite legitmate and appropriate that someone be put to death for having committed such hateful and inhuman acts. (Hurley, 153) Conclusion: Capital punishment is justified for the crimes of murder and kidnapping Premise: It is quite legitimate and appropriate that someone be put to death for having committed such hateful and inhuman acts. Note that the conclusion, that capital punishment is "justified" is the same thing as saying that it is "legitimate and appropriate" - and is therefore a restatement of the conclusion in a slightly different way. This "argument" therefore argues in a circle, since the premise supports the conclusion, and the conclusion supports the premise.   GM makes the best cars in the world today. We know this since they have the very best design engineers. The reason they have the best design engineers is because they can afford to pay them more than other car manufacturers. Obviously, they can afford to pay them more because they make the finest cars in the world. (adapted from Hurley, op cite.) In this example, the conclusion ("GM makes the best cars in the world") is stated first. The truth of this depends on each link of the chain - and ultimately on the first premise (stated last) which merely rephrases the conclusion. In this case it is easy to see why this is called "circular reasoning."   This sort of "reasoning" typically has the following form. Premises in which the truth of the conclusion is assumed true. Claim C (the conclusion) is true. This sort of "reasoning" is fallacious because simply assuming that the conclusion is true (directly or indirectly) in the premises does not constitute evidence for that conclusion. Obviously, simply assuming a claim is true does not serve as evidence for that claim. This is especially clear in particularly blatant cases: "X is true. The evidence for this claim is that X is true." More Examples: Bill: "God must exist." Jill: "How do you know." Bill: "Because the Bible says so." Jill: "Why should I believe the Bible?" Bill: "Because the Bible was written by God."   "If such actions were not illegal, then they would not be prohibited by the law."   "The belief in God is universal. After all, everyone believes in God."   Interviewer: "Your resume looks impressive but I need another reference." Bill: "Jill can give me a good reference." Interviewer: "Good. But how do I know that Jill is trustworthy?" Bill: "Certainly. I can vouch for her."   Since I'm not lying, it follows that I'm telling the truth.   We know that God exists, since the Bible says God exists.   What the Bible says must be true, since God wrote it and God never lies.   Since firefighters must be strong men willing to face danger every day, it follows that no woman can be a firefighter." (Although arguments of this sort are formally valid because it is impossible for their conclusions to be false if their premises are true, they fail to provide logical support for their conclusions, which have already been accepted without proof at the outset.) Resolution: Show that in order to believe that the premises are true we must already agree that the conclusion is true. References: Barker: 159, Cedarblom and Paulsen: 144, Copi and Cohen: 102, Davis: 33; Hurley, 152. << Return

Hebrew for Christians Copyright © John J. Parsons All rights reserved.

LOGIC l "Appeal to Ignorance" l (Burden of Proof) l John J Parsons l Bible Teaching University l NIGHT SCHOOL

Appeal to Ignorance

When the premises of an argument affirm that nothing has been proved about something, and the conclusion makes a definite assertion about that thing, the argument commits an appeal to ignorance.   Examples: People have tried for centuries to prove the claims of astrology, but no one has ever succeeded. Therefore we must conclude that astrology is a lot of baloney.   People have tried for centuries to disprove the claims of astrology, but no one has ever succeeded. Therefore we must conclude that astrology is a valid way of experiencing the world. This fallacy is also sometimes called "Burden of Proof," since the burden of proof is placed on the wrong side. Another version occurs when a lack of evidence for side A is taken to be evidence for side B in cases in which the burden of proof actually rests on side B. In many situations, one side has the burden of proof resting on it. This side is obligated to provide evidence for its position. The claim of the other side, the one that does not bear the burden of proof, is assumed to be true unless proven otherwise. The difficulty in such cases is determining which side, if any, the burden of proof rests on. In many cases, settling this issue can be a matter of significant debate. In some cases the burden of proof is set by the situation. For example, in American law a person is assumed to be innocent until proven guilty (hence the burden of proof is on the prosecution). As another example, in debate the burden of proof is placed on the affirmative team. As a final example, in most cases the burden of proof rests on those who claim something exists (such as Bigfoot, psychic powers, universals, and sense data). Examples: Bill: "I think that we should invest more money in expanding the interstate system." Jill: "I think that would be a bad idea, considering the state of the treasury." Bill: "How can anyone be against highway improvements?"   Bill: "I think that some people have psychic powers." Jill: "What is your proof?" Bill: "No one has been able to prove that people do not have psychic powers."   "You cannot prove that God does not exist, so He does."   You cannot prove that God exists, therefore He doesn't.   Arguments of this form assume that since something has not been proven false, it is therefore true. Conversely, such an argument may assume that since something has not been proven true, it is therefore false. (This is a special case of a false dilemma, since it assumes that all propositions must either be known to be true or known to be false.) As Davis writes, "Lack of proof is not proof." (p. 59) More Examples: Since you cannot prove that ghosts do not exist, they must exist.   Since scientists cannot prove that global warming will occur, it probably won't.   Fred said that he is smarter than Jill, but he didn't prove it, so it must be false.   Proof: Identify the proposition in question. Argue that it may be true even though we don't know whether it is or isn't. References: Copi and Cohen: 93, Davis: 59 << Return

Hebrew for Christians Copyright © John J. Parsons All rights reserved.

LOGIC l "Informal Fallacies" l John J. Parsons l University of the Bible l NIGHT SCHOOL

Informal Fallacies

The interpretation of a Biblical text is only as good as the underlying logic that supports it. God made man in His image (tzelem) and likeness (demut), and therefore made him with rationality and the ability to correctly reason about things. The Lord Jesus the Messiah is described as the "Logos" or "logic" of God, and we are called to follow Him as His talmidim (students or disciples). You simply cannot properly begin to properly read the various texts of Scripture without first being grounded in the basics of clear thinking. This section lists some common errors in thinking that afflict all of us since the fall of Adam in Gan Eden. By familiarizing yourself with these forms of reasoning you may guard yourself from making the same sorts of errors (as well as to catch errors in the thinking of others who purport to be speaking the truth). For a brief introduction of the subject, click here. Fallacies of Presumption  These arguments illicitly assume the truth of their conclusion: Appeal to Ignorance: (ad Ignorantiam) Because something is not known to be true, it is assumed to be false (or conversely).   Begging the Question: (Petitio Principii) The truth of the conclusion is already assumed in the premises.   Complex Question: Two unrelated points are conjoined as a single proposition.   False Dilemma: Two choices are given when in fact there are three (or more) options.   Hegelian Fallacy It is assumed that the middle position between two extremes must be correct simply because it is the middle position. Named after the philosopher G. W. Hegel (1770-1831), the target of Soren Kierkegaard's ruthless (and prophetic) irony.   Pseudo-Tolerance: The assumption that "I must respect all opinions" (or some variation) ends the need for further consideration of an issue.   Relativist Fallacy: A person rejects a claim by asserting that the claim might be true for others but is not for him/her.   Who is to say? Affecting a skeptical attitude with the rhetorical "Who is to say?" question is supposed to "prove" that there is no way to decide whether any position or view is better than another. Assumes that the truth is unknowable.   Non Sequiturs The term non sequitur literally means "it does not follow." In this section we describe fallacies which occur as a consequence of invalid arguments: Affirming the Consequent: Any argument of the form: If p then q, q, therefore p.   Denying the Antecedent: Any argument of the form: If p then q, not p, therefore, not q.   Inconsistency: Asserting that contrary or contradictory statements are both true.   Missing the Point (Ignoratio Elenchi) An argument in defense of one conclusion instead proves a different conclusion.   Changing the SubjectThe fallacies in this section change the subject by discussing the person making the argument instead of discussing reasons to believe or disbelieve the conclusion. Attacking the Person: (ad hominem) (a) the person's character is attacked (abusive) (b) the person's circumstances are noted (circumstantial) (c) the person does not practice what is preached (tu quoque)   Appeal to Authority: (ad verecundiam) The fact that some sort of authority states something does not, in general, serve as evidence that the claim is true. This is especially true if: (a) the authority is not an expert in the field (b) experts in the field disagree (c) the authority was joking, drunk, or in some other way not being serious (d) the authority in question is not named (anonymous authority)   Style Over Substance: The manner in which an argument (or arguer) is presented is felt to affect the truth of the conclusion.   Red Herring: An irrelevant topic is presented in order to divert attention from the original issue.   Genetic Fallacy: A perceived defect in the origin of a claim or thing is taken to be evidence that discredits the claim or thing itself.   Poisoning the Wells: Trying to discredit what a person might later claim by presenting unfavorable information.   Straw Man: Attack an argument different from (and weaker than) the opposition's best argument.   Appeals to Ulterior Motives The fallacies in this section have in common the practice of appealing to emotions or other psychological factors. In this way, they do not provide reasons for belief. Appeal to belief: The fact that many people believe a claim does not, in general, serve as evidence that the claim is true.   Appeal to Common Practice: The fact that most people do X is used as "evidence" to support the action or practice.   Appeal to (fearful) Consequences: You are warned of unacceptable consequences.   Appeal to Emotion: The substitution of various means of producing strong emotions in place of evidence for a claim.   Appeal to Flattery: Flattery is used in the place of evidence for accepting a claim.   Appeal to Force: Creating fear in people does not constitute evidence for a claim.   Appeal to Novelty: It is assumed that something is better or correct simply because it is new.   Appeal to Popularity: (ad Populum) A proposition is argued to be true because it is widely held to be true.   Appeal to Pity: (ad Misericordiam) You are persuaded to agree by sympathy.   Appeal to Ridicule: Mocking a claim does not show that it is false.   Appeal to Tradition: It is assumed that something is better or correct simply because it is older, traditional, or "always has been done."   Bandwagon: Peer pressure and threat of rejection do not constitute evidence for accepting or rejecting a claim.   Guilt by Association: A person rejects a claim because it is pointed out that people she dislikes accept the claim.   Prejudicial Language: Value or moral goodness is attached to believing the author.   Inductive FallaciesInductive reasoning consists of inferring from the properties of a sample to the properties of a population as a whole. Accident: A generalization is applied when circumstances suggest that there should be an exception.   Hasty Generalization: (converse accident) The sample is too small to support an inductive generalization about a population   Unrepresentative Sample: A conclusion is drawn about a population based on a sample that is biased or prejudiced in some manner.   False Analogy: Two objects or events being compared are relevantly dissimilar.   Slothful Induction: The conclusion of a strong inductive argument is denied despite the evidence to the contrary.   Fallacy of Exclusion: Evidence which would change the outcome of an inductive argument is excluded from consideration.   Special Pleading: Claiming to be exempt from certain principles or standards without providing good reasons for the exemption.   Spotlight: A person uncritically assumes that all members or cases of a certain class or type are like those that receive the most attention or coverage in the media.   The Gambler's Fallacy: A person assumes that a departure from what occurs on average or in the long term will be corrected in the short term.   Misleading Vividness: A very small number of particularly dramatic events are taken to outweigh a significant amount of statistical evidence.   Causal FallaciesIt is common for arguments to conclude that one thing causes another. But the relation between cause and effect is a complex one. It is easy to make a mistake. Post Hoc: Because one thing follows another, it is held to cause the other.   Questionable Cause: One event is claimed to cause another just because the events occur together.   Insignificant: One thing is held to cause another, and it does, but it is insignificant compared to other causes of the effect.   Wrong Direction: The direction between cause and effect is reversed.   Complex Cause: The cause identified is only a part of a number of causes of the effect.   Slippery Slope: A series of increasingly unacceptable consequences is drawn.   False Analogies These fallacies occur because the author mistakenly assumes that the whole is nothing more than the sum of its parts. However, things joined together may have different properties as a whole than any of them do separately: Composition: Because the attributes of the parts of a whole have a certain property, it is argued that the whole has that property.   Division: Because the whole has a certain property, it is argued that the parts have that property.   Fallacies of Definition In order to make our words or concepts clear, we use a definition. The purpose of a definition is to state exactly what a word means. A good definition should enable a reader to 'pick out' instances of the word or concept with no outside help. Too Broad: The definition includes items which should not be included.   Too Narrow: The definition does not include all the items which should be included.   Failure to Elucidate: The definition is more difficult to understand than the word or concept being defined.   Circular Definition: The definition includes the term being defined as a part of the definition.   Self-Stultifying Conditions: The definition is self-contradictory.   Fallacies of AmbiguityThe fallacies in this section are all cases where a word or phrase is used unclearly. There are two ways in which this can occur: (1) The word or phrase may be ambiguous, in which case it has more than one distinct meaning; or (2) the word or phrase may be vague, in which case it has no distinct meaning: Equivocation: The same term is used with two different meanings.   Amphiboly: The structure of a sentence allows two different interpretations.   Accent: The emphasis on a word or phrase suggests a meaning contrary to what the sentence actually says.   Fallacies of Explanation An explanation is a form of reasoning which attempts to answer the question "why?" For example, it is with an explanation that we answer questions such as, "Why is the sky blue?" Subverted Support: The phenomenon being explained doesn't exist.   Non-support: Evidence for the phenomenon being explained is biased.   Untestability: The theory which explains cannot be tested.   Limited Scope: The theory which explains can only explain one thing.   Limited Depth: The theory which explains does not appeal to underlying causes.   Syllogistic Fallacies These fallacies pertain to categorical statements based on traditional (Aritotelian) logic. Fallacy of Four Terms: A syllogism has four terms   Undistributed Middle: Two separate categories are said to be connected because they share a common property   Illicit Major: The predicate of the conclusion talks about all of something, but the premises only mention some cases of the term in the predicate   Illicit Minor: The subject of the conclusion talks about all of something, but the premises only mention some cases of the term in the subject   Fallacy of Exclusive Premises: A syllogism has two negative premises   Fallacy of Drawing an Affirmative Conclusion From a Negative Premise: As the name implies   Existential Fallacy: A particular conclusion is drawn from universal premises.     Credits I relied on the following sources to confirm my work for this portion of the Hebrew for Christians web site: Barker, Stephen F., The Elements of Logic. Fifth Edition.McGraw-Hill, 1989 Copi, Irving M. and Cohen, Carl. Introduction to Logic. Eighth Edition. Macmillan, 1990 Purtill, Richard L., Logic for Philosophers. Harper and Row, 1971 Hurley, Patrick, A Concise Introduction to Logic, 7th ed. (Wadsworth, 2000). [My personal favorite for a good overview of the subject.] Engel, S. Morris, With Good Reason: An Introduction to Informal Fallacies (St. Martin's, 1994) Stephen's Guide to the Logical Fallacies Dr. Michael C. Labossiere, the author of a Macintosh tutorial called Fallacy Tutorial Pro 3.0, has graciously agreed to let me use portions of his work to appear on this site. Portions remain © Copyright 1995 Michael C. Labossiere. Dr. Labossiere may be reached at ontologist@aol.com. << Return

Hebrew for Christians Copyright © John J. Parsons All rights reserved.