In my last Friday Fallacy post, I looked at the fallacy of denying the antecedent. There I discussed conditional statements, statements of the form “if P then Q”. Examples would be statements such as “if it is raining then the grass will be wet” or “if the US had not shot Bin Laden then he would still be alive”. I noted that conditionals have an “antecedent” and a … [Read more...]
Apologetics is Alive: People are Hungry for Answers
By Matthew Flannagan. Here in New Zealand, I am often told by evangelical leaders that we now live in a post-modern society, which has moved beyond “arguments” and that Apologetics is an outdated “modernist concept.” They say we need instead to “tell the story” so that people will see the "meta-narrative of scripture"—whatever exactly that means. Last night, Madeleine and I … [Read more...]
Fallacy Friday: Denying the Antecedent
This week I will look at the fallacy of denying the antecedent. Before I can elaborate exactly what is involved in this fallacy, it is important to introduce and analyse some valid arguments that are superficially similar. Modus Ponens One of the very first valid inferences one learns in logic is modus ponens. To use the well worn example that was repeated ad nauseam when I … [Read more...]
Friday Fallacy: Equivocation
In my post on Assessing Arguments I noted that a valid argument is one where it is impossible for the premises to be true and the conclusion false. I gave the following example: Premise: All men are under 10 feet tall; Premise: John is a man; Conclusion: John is under 10 feet tall. This argument is valid because it is impossible for both premises to be true and the conclusion … [Read more...]
Fallacy Friday: Ad Ignorantiam (Arguments from Ignorance)
In the discussion following last week’s Fallacy Friday topic, Ad Populum, LJ asked about the ad ignorantiam fallacy. In particular she wanted to know about its relationship to creationism. I suspect LJ was being sarcastic but despite this it is worth exploring this issue a bit. First, we should recall that a fallacy is not simply a false position on some subject. The fact that … [Read more...]
Fallacy Friday: Ad Populum (Appeals to Popularity)
This week I am going to look at the ad populum fallacy. Ad populum is Latin for “appeal to the people”. This fallacy occurs when a person argues that a particular claim is true because a large number of people accept it. Put crudely it contends that a position is true because it is popular – a majority of people, or a majority of one’s peers accept it. Appeals to what others … [Read more...]
Fallacy Friday: Ad Misericordiam (Appeal to Pity)
This week I will look at the ad misericordiam fallacy, the fallacy of appealing to pity. Perhaps the best example I have come across is one used by my friend Francis Beckwith; In his book Politically Correct Death: Answering Arguments for Abortion Rights, Beckwith cites the following letter to the editor: The fallacy in this letter is not difficult to spot; it is an argument … [Read more...]
Fallacy Friday: Petitio Principii (Begging the Question)
For the last few Fridays I have been publishing a blog series on logical fallacies. This begs the question, what fallacy will I discuss today? The above sentence illustrates how the phrase “begs the question” is commonly misused. To test how pervasive this misuse is I typed “this begs the question” into Google and limited it to New Zealand; every single result on the first … [Read more...]
Fallacy Friday: The Fallacy of False Cause & Post Hoc, Ergo Propter Hoc
This week I will look at the fallacy of false cause and in particular the post hoc, ergo propter hoc fallacy. These fallacies occur when one conflates the fact that two things occur at the same time or in close succession with the conclusion that one caused the other. Post Hoc, Ergo Propter Hoc This neat little clip from the West Wing gives a good example: … [Read more...]
Fallacy Friday: Division and Composition
Today I want to look at two fallacies, the fallacy of composition and the fallacy of division. These two fallacies are related in that they both mistakenly confuse what is true of the parts with what is true of the whole. The Fallacy of Composition The fallacy of composition involves mistakenly reasoning that what is true of all the parts of something is therefore true of the … [Read more...]