1. The core fallacies
8. The fallacy of ignoratio elenchi, or irrelevant conclusion, is indicative of misdirection in argumentation rather than a weak inference. The claim that Calgary is the fastest growing city in Canada, for example, is not defeated by a sound argument showing it is not the biggest city in Canada. A variation of ignoratio elenchi, known under the name of the straw man fallacy, occurs when an opponent’s point of view is distorted in order to make it easier to refute. For example, in opposition to a proponent’s view that (a) industrialization is the cause of global warming, an opponent might substitute the proposition that (b) all ills that beset mankind are due to industrialization and then, having easily shown that (b) is false, leave the impression that (a) too is false. Two things went wrong: the proponent does not hold (b), and even if she did, the falsity of (b) does not imply the falsity of (a).
There are a number of common fallacies that begin with the Latin prefix ‘ad’ (‘to’ or ‘toward’) and the most common of these will be described next.
2. History of Fallacy Theory
Isaac Watts in his Logick; or, The Right Use of Reason (1724), furthered the ad-argument tradition by adding three more arguments: argumentum ad fidem (appeal to faith), argumentum ad passiones (appeal to passion), and argumentum ad populum (a public appeal to passions). Like Locke, Watts does not consider these arguments as fallacies but as kinds of arguments. However, the Logick does consider sophisms and introduces “false cause” as an alternative name for causa non pro causa which here, as in the Port-Royal Logic, is understood as a fallacy associated with empirical causation. According to Watts it occurs whenever anyone assigns “the reasons of natural appearances, without sufficient experiments to prove them” (1796, Pt. III, 3 i 4). Another sophism included by Watts is imperfect enumeration or false induction, the mistake of generalizing on insufficient evidence. Also, the term ‘strawman fallacy’ may have its origins in Watts’s discussion of ignoratio elenchi: after having dressed up the opinions and sentiments of their adversaries as they please to make “images of straw”, disputers “triumph over their adversary as though they had utterly confuted his opinions” (1796, Pt. III 3 i 1).
3. New approaches to fallacies
3.6 Dialectical/dialogical approaches to fallacies
Walton divides fallacies into two kinds: paralogisms and sophisms. A paralogism is “the type of fallacy in which an error of reasoning is typically committed by failing to meet some necessary requirement of an argumentation scheme” whereas “the sophism type of fallacy is a sophistical tactic used to try to unfairly get the best of a speech partner in an exchange of arguments” (2010, 171; see also 1995, 254). Paralogisms are instances of identifiable argumentation schemes, but sophisms are not. The latter are more associated with infringing a reasonable expectation of dialogue than with failing some standard of argument, (2011, 385; 2010, 175). A further distinction is drawn between arguments used intentionally to deceive and arguments that merely break a maxim of argumentation unintentionally. The former count as fallacies, the latter, less condemnable, are blunders (1995, 235).
Among the informal paralogisms Walton includes: ad hominem, ad populum, ad misericordiam, ad ignorantiam, ad verecundiam, slippery slope, false cause, straw man, argument from consequences, faulty analogy, composition and division. In the category of sophisms he places ad baculum, complex question, begging the question, hasty generalization, ignoratio elenchi, equivocation, amphiboly, accent, and secundum quid. He also has a class of formal fallacies very much the same as those identified by Whately and Copi. The largest class in Walton’s classification is the one associated with argumentation schemes and ad-arguments, and these are the ones that he considers as the most central fallacies. Nearly all the Aristotelian fallacies included find themselves relegated to the less studied categories of sophisms. Taking a long look at the history of fallacies, then, we find that the Aristotelian fallacies are no longer of central importance. They have been replaced by the fallacies associated with the ad-arguments.
4. Current issues in fallacy theory
Recently there has been renewed interest in how biases are related to fallacies. Correia (2011) has taken Mill’s insight that biases are predisposing causes of fallacies a step further by connecting identifiable biases with particular fallacies. Biases can influence the unintentional committing of fallacies even where there is no intent to be deceptive, he observes. Taking biases to be “systematic errors that invariably distort the subject’s reasoning and judgment,” the picture drawn is that particular biases are activated by desires and emotions (motivated reasoning) and once they are in play, they negatively affect the fair evaluation of evidence. Thus, for example, the “focussing illusion” bias inclines a person to focus on just a part of the evidence available, ignoring or denying evidence that might lead in another direction. Correia (2011, 118) links this bias to the fallacies of hasty generalization and straw man, suggesting that it is our desire to be right that activates the bias to focus more on positive or negative evidence, as the case may be. Other biases he links to other fallacies.