Logical Fallacies Created by J. Nelson

Ad Hominem (Personal Attack) Arguments of this kind focus not on the evidence for a view but on the character of the person advancing it; they seek to discredit positions by discrediting those who hold them. Example (1) William Dembski argues that modern biology supports the idea that there is an intelligent designer who created life. (2) Dembski would say that because he’s religious. Therefore: (3) Modern biology doesn’t support intelligent design.

Bandwagon Fallacy The bandwagon fallacy is committed by arguments that appeal to the growing popularity of an idea as a reason for accepting it as true. They take the mere fact that an idea suddenly attracting adherents as a reason for us to join in with the trend and become adherents of the idea ourselves. Example (1) Increasingly, people are coming to believe that Eastern religions help us to get in touch with our true inner being. Therefore: (2) Eastern religions help us to get in touch with our true inner being.

Appeal to Antiquity / Tradition Appeals to antiquity assume that older ideas are better, that the fact that an idea has been around for a while implies that it is true. Example (1) Religion dates back many thousands of years (whereas atheism is a relatively recent development). Therefore: (2) Some form of religion is true.

Appeal to Authority An appeal to authority is an argument from the fact that a person judged to be an authority affirms a proposition to the claim that the proposition is true. Example (1) Marilyn vos Savant says that no philosopher has ever successfully resolved the problem of evil. Therefore: (2) No philosopher has ever successfully resolved the problem of evil.

Appeal to Popularity Appeals to popularity suggest that an idea must be true simply because it is widely held. Example (1) Most people believe in a god or ‘higher power’. Therefore: (2) God, or at least a higher power, must exist.

The Moralistic Fallacy The moralistic fallacy moves from statements about how things ought to be to statements about how things are; it assumes that the world is as it should be. Crossing a one way street without looking both ways under the belief that the world works the way it ought to.

The Naturalistic Fallacy An argument whose premises merely describe the way that the world is, but whose conclusion describes the way that the world ought to be Examples (1) Feeling envy is only natural. Therefore: (2) There’s nothing wrong with feeling envy.

Red Herring It is a fallacy of distraction, and is committed when a listener attempts to divert an arguer from his argument by introducing another topic. “You may think that he cheated on the test, but look at the poor little thing! How would he feel if you made him sit it again?”

Weak Analogy Arguments by analogy rest on a comparison. Their logical structure is this: (1) A and B are similar. (2) A has a certain characteristic. Therefore: (3) B must have that characteristic too. The weak analogy fallacy (or “false analogy”, or “questionable analogy”) is committed when the comparison is not strong enough. Example Bananas and telephones are both shaped to fit our face, so bananas must, like telephones, be designed.

Equivocation The fallacy of equivocation is committed when a term is used in two or more different senses within a single argument. (1) The church would like to encourage theism. (2) Theism is a medical condition resulting from the excessive consumption of tea. Therefore: (3) The church ought to distribute tea more freely.

Straw Man Arguments A straw man argument is one that misrepresents a position in order to make it appear weaker than it actually is, refutes this misrepresentation of the position, and then concludes that the real position has been refuted. (1) Trinitarianism holds that three equals one. (2) Three does not equal one. Therefore: (3) Trinitarianism is false.

Affirming the Consequent The fallacy of affirming the consequent is committed by arguments that have the form: (1) If A then B (2) B Therefore: (3) A The first premise of such arguments notes that if a state of affairs A obtained then a consequence B would also obtain. The second premise asserts that this consequence B does obtain. The faulty step then follows: the inference that the state of affairs A obtains. (1) If Zeus was a real, historical figure, but the Catholic Church covered up his existence, then we wouldn’t have any evidence of a historical Zeus today. (2) We don’t have any evidence of a historical Zeus today. Therefore: (3) Zeus was a real, historical figure, but the Catholic Church covered up his existence.

Argument from Ignorance Arguments from ignorance infer that a proposition is true from the fact that it is not known to be false. (1) No one has been able to disprove the existence of God. Therefore: (2) God exists.

Begging the Question / Circular Reasoning An argument is circular if its conclusion is among its premises, if it assumes (either explicitly or not) what it is trying to prove. (1) The Bible affirms that it is inerrant. (2) Whatever the Bible says is true. Therefore: (3) The Bible is inerrant.

Complex Question The complex question fallacy is committed when a question is asked (a) that rests on a questionable assumption, and (b) to which all answers appear to endorse that assumption. "Have you stopped beating your wife?"

Cum Hoc Ergo Propter Hoc The cum hoc fallacy is committed when it is assumed that because two things occur together, they must be causally related. This, however, does not follow; correlation is possible without causation. “People who eat Shredded Wheat tend to have healthy hearts.”

Bifurcation / False Dilemma The bifurcation fallacy is committed when a false dilemma is presented, i.e. when someone is asked to choose between two options when there is at least one other option available. (1) Either a Creator brought the universe into existence, or the universe came into existence out of nothing. (2) The universe didn’t come into existence out of nothing (because nothing comes from nothing). Therefore: (3) A Creator brought the universe into existence.

Hasty Generalization A hasty generalization draws a general rule from a single, perhaps atypical, case. It is the reverse of a sweeping generalization.sweeping generalization (1) My Christian / atheist neighbor is a real grouch. Therefore: (2) Christians / atheists are grouches.

Post Hoc Ergo Propter Hoc The post hoc fallacy is committed when it is assumed that because one thing occurred after another, it must have occurred as a result of it. Mere temporal succession, however, does not entail causal succession. (1) Most people who are read the last rites die shortly afterwards. Therefore: (2) Priests are going around killing people with magic words!

Slippery Slope Slippery slope arguments falsely assume that one thing must lead to another. They begin by suggesting that if we do one thing then that will lead to another, and before we know it we’ll be doing something that we don’t want to do. They conclude that we therefore shouldn’t do the first thing. (1) If you buy a Green Day album, then next you’ll be buying Buzzcocks albums, and before you know it you’ll be a punk with green hair and everything. (2) You don’t want to become a punk. Therefore: (3) You shouldn’t buy a Green Day album.

Sweeping Generalization A sweeping generalization applies a general statement too broadly. If one takes a general rule, and applies it to a case to which, due to the specific features of the case, the rule does not apply. (1) Children should be seen and not heard. (2) Little Wolfgang Amadeus is a child. Therefore: (3) Little Wolfgang Amadeus shouldn’t be heard.

Tu Quoque (Two Wrongs Don’t Make a Right) The tu quoque fallacy is committed when it is assumed that because someone else has done a thing there is nothing wrong with doing it. (1) The Romans kept slaves. Therefore: (2) We can keep slaves too.

‘No True Scotsman’ The no true Scotsman fallacy is a way of reinterpreting evidence in order to prevent the refutation of one’s position. Proposed counter-examples to a theory are dismissed as irrelevant solely because they are counter-examples, but purportedly because they are not what the theory is about. (1) Angus puts sugar on his porridge. (2) No (true) Scotsman puts sugar on his porridge. Therefore: (3) Angus is not a (true) Scotsman. Therefore: (4) Angus is not a counter- example to the claim that no Scotsman puts sugar on his porridge.