In this example, the two choices are presented as the only options, yet the author ignores a range of choices in between such as developing cleaner technology, car-sharing systems for necessities and emergencies, or better community planning to discourage daily driving. Ad hominem: This is an attack on the character of a person rather than his or her opinions or arguments.
In this example, the author doesn't even name particular strategies Green Peace has suggested, much less evaluate those strategies on their merits. Instead, the author attacks the characters of the individuals in the group. Getting on the bandwagon is one such instance of an ad populum appeal. If you were a true American you would support the rights of people to choose whatever vehicle they want.
In this example, the author equates being a "true American," a concept that people want to be associated with, particularly in a time of war, with allowing people to buy any vehicle they want even though there is no inherent connection between the two.
Red Herring: This is a diversionary tactic that avoids the key issues, often by avoiding opposing arguments rather than addressing them. The level of mercury in seafood may be unsafe, but what will fishers do to support their families? In this example, the author switches the discussion away from the safety of the food and talks instead about an economic issue, the livelihood of those catching fish.
While one issue may affect the other it does not mean we should ignore possible safety issues because of possible economic consequences to a few individuals. Straw Man: This move oversimplifies an opponent's viewpoint and then attacks that hollow argument.
In this example, the author attributes the worst possible motive to an opponent's position. In reality, however, the opposition probably has more complex and sympathetic arguments to support their point.
By not addressing those arguments, the author is not treating the opposition with respect or refuting their position. Moral Equivalence: This fallacy compares minor misdeeds with major atrocities, suggesting that both are equally immoral.
In this example, the author is comparing the relatively harmless actions of a person doing their job with the horrific actions of Hitler. Within these two categories, he identified 13 individual fallacies. Through time we have reclassified fallacies using various typologies and criteria. For our purposes, we will focus on formal and informal fallacies.
Skip to main content. Module Four: Delivery of Demonstration Speeches. The one has to do with semantical ambiguity, the other with syntactical ambiguity. However, the way that Aristotle thought of the combination and division fallacies differs significantly from modern treatments of composition and division. For division, Aristotle gives the example of the number 5: it is 2 and 3. But 2 is even and 3 is odd, so 5 is even and odd.
Finally, the fallacy that Aristotle calls form of expression exploits the kind of ambiguity made possible by what we have come to call category mistakes, in this case, fitting words to the wrong categories.
Category confusion was, for Aristotle, the key cause of metaphysical mistakes. There are seven kinds of sophistical refutation that can occur in the category of refutations not dependent on language: accident, secundum quid , consequent, non-cause, begging the question, ignoratio elenchi and many questions.
It turns on his distinction between two kinds of predication, unique properties and accidents Top. What belongs to a thing are its unique properties which are counterpredicable Smith , 60 , i. However, attributes that are accidents are not counterpredicates and to treat them as such is false reasoning, and can lead to paradoxical results; for example, if it is a property of triangles that they are equal to two right angles, and a triangle is accidentally a first principle, it does not follow that all first principles have two right angles see Schreiber , ch.
Aristotle considers the fallacy of consequent to be a special case of the fallacy of accident, observing that consequence is not convertible, i. This fallacy is sometimes claimed as being an early statement of the formal fallacy of affirming the consequent.
The fallacy of secundum quid comes about from failing to appreciate the distinction between using words absolutely and using them with qualification. It is because the difference between using words absolutely and with qualification can be minute that this fallacy is possible, thinks Aristotle. Begging the question is explained as asking for the answer the proposition which one is supposed to prove, in order to avoid having to make a proof of it.
Some subtlety is needed to bring about this fallacy such as a clever use of synonymy or an intermixing of particular and universal propositions Top. VIII, If the fallacy succeeds the result is that there will be no deduction: begging the question and non-cause are directly prohibited by the second and third conditions respectively of being a deduction SR 6 b The fallacy of non-cause occurs in contexts of ad impossibile arguments when one of the assumed premises is superfluous for deducing the conclusion.
The superfluous premise will then not be a factor in deducing the conclusion and it will be a mistake to infer that it is false since it is a non-cause of the impossibility. This is not the same fallacy mentioned by Aristotle in the Rhetoric II 24 which is more akin to a fallacy of empirical causation and is better called false cause see Woods and Hansen Thus with a single answer to two questions one has two premises for a refutation , and one of them may turn out to be idle, thus invalidating the deduction it becomes a non-cause fallacy.
Also possible is that extra-linguistic part-whole mistakes may happen when, for example, given that something is partly good and partly not-good, the double question is asked whether it is all good or all not-good? Either answer will lead to a contradiction see Schreiber , — Despite its name, this fallacy consists in the ensuing deduction, not in the question which merely triggers the fallacy.
Seen this way, ignoratio elenchi is unlike all the other fallacies in that it is not an argument that fails to meet one of the criteria of a good deduction, but a genuine deduction that turns out to be irrelevant to the point at issue.
Each of the other twelve fallacies is analysed as failing to meet one of the conditions in this definition of refutation SR 6. Aristotle seems to favour this second reading, but it leaves the problem of explaining how refutations that miss their mark can seem like successful refutations. A possible explanation is that a failure to contradict a given thesis can be made explicit by adding the negation of the thesis as a last step of the deduction, thereby insuring the contradiction of the thesis, but only at the cost by the last step of introducing one of the other twelve fallacies in the deduction.
To really understand them a much longer engagement with the original text and the secondary sources is necessary. This approach to the fallacies is continued in contemporary research by some argumentation theorists, most notably Douglas Walton who also follows Aristotle in recognizing a number of different kinds of dialogues in which argumentation can occur; Frans van Eemeren and Rob Grootendorst who combine dialectical and pragmatic insights with an ideal model of a critical discussion; and Jaakko Hintikka who analyses the Aristotelian fallacies as mistakes in question-dialogues Hintikka ; Bachman Francis Bacon deserves a brief mention in the history of fallacy theory, not because he made any direct contribution to our knowledge of the fallacies but because of his attention to prejudice and bias in scientific investigation, and the effect they could have on our beliefs.
He spoke of false idols , aphorisms 40—44 as having the same relation to the interpretation of nature that fallacies have to logic. The idol of the tribe is human nature which distorts our view of the natural world it is a false mirror. The idol of the cave is the peculiarity of each individual man, our different abilities and education that affect how we interpret nature.
These three idols all fall into the category of explanations of why we may misperceive the world. The view of The New Organon is that just as logic is the cure for fallacies, so will the true method of induction be a cure for the false idols.
III, xix. The division is not exclusive, with some of the sophisms fitting both classes. Several kinds of causal errors are considered under the broad heading, non causa pro causa and they are illustrated with reference to scientific explanations that have assigned false causes for empirical phenomena.
III, xix 3. Begging the questions is included and illustrated, interestingly, with examples drawn from Aristotelian science. Two new sophisms are included: one is imperfect enumeration, the error of overlooking an alternative, the other is a faulty incomplete induction, what we might call hasty generalization.
Although the discussions here are brief, they mark the entry of inductive fallacies into the pool of present day recognized fallacies. III, xix 1. The other Aristotelian fallacies included are accident, combination and division, secundum quid and ambiguity. The sophisms of everyday life and ordinary discourse are eight in number and two of them, the sophisms of authority and manner, should be noticed.
In these sophisms, external marks of speakers contribute to the persuasiveness of their arguments. Although authority is not to be doubted in church doctrines, in matters that God has left to the discernment of humans we can be led away from the truth by being too deferential. Here we find one of the earliest statements of the modern appeal to false authority: people are often persuaded by certain qualities that are irrelevant to the truth of the issue being discussed.
Thus there are a number of people who unquestioningly believe those who are the oldest and most experienced, even in matters that depend neither on age nor experience, but only on mental insight Bk. III, xx 6. To age and experience Arnauld and Nicole add noble birth as an unwarranted source of deference in matters intellectual Bk. III, xx 8. The authors seem to have the rhetorical flourishes of royal courtiers especially in mind.
It is John Locke who is credited with intentionally creating a class of ad -arguments, and inadvertently giving birth to the class of ad -fallacies. Two of the ad arguments have developed beyond how Locke originally conceived them. His characterization of the ad verecundiam is considered the locus classicus of appeal-to-authority arguments. It seems unlikely, however, that Locke thought we should never rely on the expertise and superior knowledge of others when engaged in knowledge-gathering and argumentation.
This leads us to consider what kind of authority Locke might have had in mind. The argumentum ad hominem , as Locke defined it, has subsequently developed into three different fallacies. To argue that way is not a fallacy but an acceptable mode of argumentation. Henry Johnstone thought it captured the essential character of philosophical argumentation. Recent scholarship suggests that these post-Lockean kinds of ad hominem arguments are sometimes used fairly, and sometimes fallaciously; but none of them is what Locke described as the argumentum ad hominem.
Modern versions of this kind of argument take it as a fallacy to infer a proposition to be true because there is no evidence against it see Krabbe, Reasoning by syllogisms, he maintained, was neither necessary nor useful for knowledge. Was Locke the first to discuss these kinds of arguments? Subsequently more ad -arguments were added to the four that Locke identified see Watts, and Copi, below. Isaac Watts in his Logick; or, The Right Use of Reason , 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. III, 3 i 4. Another sophism included by Watts is imperfect enumeration or false induction, the mistake of generalizing on insufficient evidence. His interest was in political argumentation, particularly in exposing the different means used by parliamentarians and law makers to defeat or delay reform legislation.
Hence, it was not philosophy or science that interested him, but political debate. Fallacies he took to be arguments or topics that would through the use of deception produce erroneous beliefs in people , 3.
These tactics he or his editor divided into four classes: fallacies of authority, danger, delay and confusion. Bentham was aware of the developing ad -fallacies tradition since each of the thirty or so fallacies he described is also labelled as belonging either to the kind ad verecundiam appeal to shame or modesty , ad odium appeal to hate or contempt , ad metum appeal to fear or threats , ad quietem appeal to rest or inaction , ad judicium , and ad socordiam appeal to postponement or delay.
It discusses authority at length, identifying four conditions for reliable appeals to authority and maintaining that the failure of any one of them cancels the strength of the appeal. This characterization fits well with the way we have come to think of the ad hominem fallacy as a view disparaged by putting forth a negative characterization of its supporter or his circumstances. Bentham places the fallacies in the immediate context of debate, identifying ways in which arguers frustrate the eventual resolution of disagreements by using insinuations of danger, delaying tactics, appeals to questionable authorities and, generally, confusing issues.
Modern argumentation theorists who hold that any impediment to the successful completion of dialogical discussions is a fallacy, may find that their most immediate precursor was Bentham see Grootendorst Whately was instrumental in the revival of interest in logic at the beginning of the nineteenth century and, being committed to deductivism, he maintained that only valid deductive inferences counted as reasoning.
Thus, he took every fallacy to belong to either the class of deductive failures logical fallacies or the class of non-logical failures material fallacies. III, intro. The logical fallacies divide into the purely logical and the semi-logical fallacies. The purely logical fallacies are plain violations of syllogistic rules like undistributed middle and illicit process. The semi-logical fallacies mostly trade on ambiguous middle terms and are therefore also logical fallacies, but their detection requires extra-logical knowledge including that of the senses of terms [ 4 ] and knowledge of the subject matter Bk.
Begging the question fits under the heading of a non-logical, material fallacy in which a premise has been unduly assumed, and ignoratio elenchi is a non-logical, material fallacy in which an irrelevant conclusion has been reached.
The ad -arguments are all placed under the last division as variants of ignoratio elenchi , but they are said to be fallacies only when they are used unfairly. This kind of ad hominem fallacy can be seen as falling under the broader ignoratio elenchi category because what is proved is not what is needed.
The creation of the category of non-logical fallacies was not really a break with Aristotle as much as it was a break with what had become the Aristotelian tradition. Aristotle thought that some fallacies were due to unacceptable premises although these are not elaborated in Sophistical Refutations see section 2.
Mill held that only inductive reasoning counts as inferring and accordingly he introduces new categories as well as a new classification scheme for fallacies. Mill drew a division between the moral and the intellectual causes of fallacies. The former are aspects of human nature such as biases and indifference to truth which incline us to make intellectual mistakes.
These dispositions are not themselves fallacies. It is the intellectual errors, the actual taking of insufficient evidence as sufficient, that are fallacious. The various ways in which this can happen are what Mill took as the basis for classifying fallacies.
Mill divided the broad category of argument fallacies into two groups: those in which the evidence is distinctly conceived and those in which it is indistinctly conceived. Fallacies falling under evidence indistinctly conceived Bk. V, vii were further described as fallacies of confusion. These result from an indistinct conception of the evidence leading to a mistaking of its significance and thereby to an unsupported conclusion.
Some of the traditional Aristotelian fallacies such as ambiguity, composition and division, petitio principii , and ignoratio elenchi , are placed in this category. Although Mill followed Whately closely in his exposition of the fallacies of confusion, he does not mention any ad -arguments in connection with ignoratio elenchi. As for the category of fallacies of evidence distinctly conceived, it too is divided. The two sub-classes are fallacies of ratiocination deduction and fallacies of induction.
The deductive fallacies Bk. V, vi are those that explicitly break a rule of the syllogism, such as the three-term rule. Also included in this category is the secundum quid fallacy. He divided inductive fallacies into two further groups: fallacies of observation V, iv and fallacies of generalization Bk.
Fallacies of observation can occur either negatively or positively. Their negative occurrence consists in non-observation in which one has overlooked negatively relevant evidence. Observation fallacies occur positively when the mistake is based on something that is seen wrongly, i. Such mal-observations occur when we mistake our inferences for facts, as in our inference that the sun rises and sets Bk.
V, iv, 5. Fallacies of generalization, the other branch of inductive fallacies, result from mistakes in the inductive process which can happen in several ways. As one example, Mill pointed to making generalizations about what lies beyond our experience: we cannot infer that the laws that operate in remote parts of the universe are the same as those in our solar system Bk. V, v, 2. Another example is mistaking empirical laws stating regularities for causal laws—his example was because women as a class have not hitherto equalled men as a class, they will never be able to do so Bk.
V, v, 4. Also placed in the category of fallacies of generalization is post hoc ergo propter hoc , which tends to single out a single cause when there are in reality many contributing causes Bk. V, v, 5. V, v, 6. Mill also included what he calls fallacies of inspection, or a priori fallacies Bk. V, iii in his survey of fallacies. These consist of non-inferentially held beliefs, so they fit the belief conception of fallacies rather than the argument conception.
Even the belief in souls or ghosts is considered an a priori fallacy. Such beliefs will not withstand scrutiny, thought Mill, by the inductive method strictly applied. His classificatory scheme is original and comprehensive. Despite these considerations, the Logic is not much referenced by fallacy theorists.
Of the eighteen informal fallacies Copi discusses, eleven can be traced back to the Aristotelian tradition, and the other seven to the burgeoning post-Lockean ad -fallacy tradition. They include affirming the consequent, denying the antecedent, the fallacy of four terms, undistributed middle, and illicit major. Informal fallacies are not characterized as resembling formally valid arguments; they gain their allure some other way.
This large class of fallacies includes accident, converse accident, false cause, petitio principii , complex question, ignoratio elenchi , ad baculum , ad hominem abusive, ad hominem circumstantial, ad ignorantiam , ad misericordiam , ad populum , and ad verecundiam. The other division of informal fallacies is called fallacies of ambiguity and it includes equivocation, amphiboly, accent, composition and division.
This has the result that the new wide category of informal fallacies is a mixed bag: some of them are at bottom logical failures equivocation, composition, ad misericordiam and some are logically correct but frustrate proof begging the question, ignoratio elenchi. Hamblin , ch. Let us next consider some of these developments. We may view Fallacies as the dividing line between traditional approaches to the study of fallacies and new, contemporary approaches.
At the time of its publication it was the first book-length work devoted to fallacies in modern times. Other historically-oriented chapters include one on the Indian tradition, and one on formal fallacies.
Let us consider what came before Hamblin as the traditional approach to fallacies and what comes after him as new approaches. SDF has three necessary conditions: a fallacy i is an argument, ii that is invalid, and iii appears to be valid. These can be thought of as the argument condition, the invalidity condition and the appearance condition. All three conditions have been brought into question. For that reason Finocchiaro prefers to speak of fallacious arguments —by which he means arguments in which the conclusion fails to follow from the premises—rather than fallacies , He further distances himself from SDF by not considering the appearance condition.
Finocchiaro distinguishes six ways in which arguments can be fallacious. As a test of completeness of this six-fold division of fallaciousness, Finocchiaro observes that it is adequate to classify all the kinds of errors which Galileo found in the arguments of the defenders of the geocentric view of the solar system. Gerald Massey has voiced a strong objection to fallacy theory and the teaching of fallacies.
He argues that there is no theory of invalidity—no systematic way to show that an argument is invalid other than to show that it has true premises and a false conclusion , Hence, there is an asymmetry between proving arguments valid and proving them invalid: they are valid if they can be shown to be an instance of a valid form, but they are not proved invalid by showing that they are an instance of an invalid form, because both valid and invalid arguments instantiate invalid forms.
Thus, showing that a natural language argument is an instance of an invalid form does not preclude the possibility that it is also an instance of a valid form, and therefore valid. In place of a sound argument—a deductively valid argument with true premises—Johnson and Blair posit an alternative ideal of a cogent argument , one whose premises are acceptable, relevant to and sufficient for its conclusion.
Acceptability replaces truth as a premise requirement, and the validity condition is split in to two different conditions, premise relevance and premise sufficiency. Acceptability is defined relative to audiences—the ones for whom arguments are intended—but the other basic concepts, relevance and sufficiency, although illustrated by examples, remain as intuitive, undefined concepts see Tindale, Premise sufficiency strength is akin to probability in that it is a matter of degree but Johnson and Blair do not pursue giving it numerical expression.
This shares only one condition with SDF: that a fallacy is an argument. Deductive validity is replaced with the broader concept sufficiency, and the appearance condition is not included.
Johnson argued that the appearance condition makes the occurrence of fallacies too subjective since how things appear may vary from perceiver to perceiver, and it should therefore be replaced by a frequency requirement. To be a fallacy, a mistake must occur with sufficient frequency to be worth our attention. The adoption of the concept of a cogent argument as an ideal has several consequences. Irrelevant premise fallacies are those with no premise support at all, whereas insufficient premise fallacies are those in which there is some support, but not enough of it.
Johnson and Blair concern themselves exclusively with informal fallacies. Many of the familiar Aristotelian fallacies that are part of the standard treatment are missing from their inventory e. This new list of fallacies has a different bent than many earlier lists, being more geared to deal with arguments in popular, everyday communication than philosophical or scientific discourse; this is evident both by the omission of some of the traditional fallacies as well as by the introduction of new ones, such as dubious assumption, two wrongs, slippery slope, and faulty analogy.
The kinds of mistakes one can make in reasoning are generally thought to be beyond enumeration and, hence, it has been maintained that there can be no complete stock of fallacies that will guard against every kind of mistake. Hence, any violation of one of the criteria of a cogent argument can be considered a fallacy.
The fallacies are then behavioural symptoms of kinds of irrationality to which humans are highly susceptible, and that makes them an important subject for study because they say something about human nature. Therefore, the problem with the standard treatment, according to Woods, is not that it is a misdirected research programme, but rather that it has been poorly carried out, partly because logicians have failed to appreciate that a multi-logical approach is necessary to understand the variety of fallacies.
This idea, pursued jointly by Woods and Douglas Walton , is that, for many of the fallacies standard formal logic is inadequate to uncover the unique kind of logical mistakes in question—it is too coarse conceptually to reveal the unique character of many of the fallacies. To get a satisfactory analysis of each of the fallacies they must be matched with a fitting logical system, one that has the facility to uncover the particular logical weakness in question.
Inductive logic can be employed for analysis of hasty generalization and post hoc ergo propter hoc ; relatedness logic is appropriate for ignoratio elenchi ; plausible reasoning theory for the ad vercundiam , and dialectical game theory for begging the question and many questions. Woods , 43 refers to this approach to studying the fallacies as methodological pluralism. Thus, like the informal logicians, there is here an interest in getting the analyses of each of the fallacies right, but the Woods and Walton approach involves embracing formal methods, not putting them aside.
The main point of this naturalizing move is that a theory of reasoning should take into account the abilities and motivations of reasoners. Past work on the fallacies has identified them as failing to satisfy the rules of either deductive or inductive logic, but Woods now wants to consider the core fallacies in light of what he calls third-way reasoning comparable to non-monotonic reasoning , an account of the cognitive practices that closely resemble our common inferential practices.
Woods illustrates his point by recalling many of the fallacies he originally identified in his paper, and subjecting them to this revised model of analysis thereby overturning the view that these types of argument are always to be spurned.
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