## 1. The core fallacies



Irving Copi's 1961 *Introduction to Logic* gives a brief
explanation of eighteen informal fallacies. Although there is some
variation in competing textbooks, Copi's selection captured what
for many was the traditional central, core
 fallacies.[1]
 In the main, these fallacies spring from two fountainheads:
Aristotle's *Sophistical Refutations* and John
Locke's *An Essay Concerning Human Understanding* (1690).
By way of introduction, a brief review of the core fallacies,
especially as they appear in introductory level textbooks, will be
given. Only very general definitions and illustrations of the
fallacies can be given. This proviso is necessary first, because, the
definitions (or identity conditions) of each of the fallacies is often
a matter of contention and so no complete or final definition can be
given in an introductory survey; secondly, some researchers wish that
only plausible and realistic instances of each fallacy be used for
illustration. This also is not possible at this stage. The advantage
of the stock examples of fallacies is that they are designed to
highlight what the mistake associated with each kind of fallacy is
supposed to be. Additional details about some of the fallacies are
found in Sections 2 and 3. As an initial working definition of the
subject matter, we may take a fallacy to be an argument that seems to
be better than it really is.



1. The fallacy of  *equivocation* is an argument which exploits
the ambiguity of a term or phrase which has occurred at least twice in
an argument, such that on the first occurrence it has one meaning and
on the second another meaning. A familiar example is:



The end of life is death.
  

Happiness is the end of life.
  

So, death is happiness.



'The end of life' first means ceasing to live, then it
means purpose. That the same set of words is used twice conceals the
fact that the two distinct meanings undermine the continuity of the
reasoning, resulting in a *non-sequitur*.



2. The fallacy of *amphiboly* is, like the fallacy of
equivocation, a fallacy of ambiguity; but here the ambiguity is due to
indeterminate syntactic structure. In the argument:



The police were told to stop drinking on campus after midnight.
  

So, now they are able to respond to emergencies much better than
before



there are several interpretations that can be given to the premise
because it is grammatically ambiguous. On one reading it can be taken
to mean that it is the police who have been drinking and are now to
stop it; this makes for a plausible argument. On another reading what
is meant is that the police were told to stop others (e.g., students)
from drinking after midnight. If that is the sense in which the
premise is intended, then the argument can be said to be a fallacy
because despite initial appearances, it affords no support for the
conclusion.



3 & 4. The fallacies of *composition* and *division*
occur when the properties of parts and composites are mistakenly
thought to be transferable from one to the other. Consider the two
sentences:


1. Every member of the investigative team was an excellent
researcher.
2. It was an excellent investigative team.



Here it is 'excellence' that is the property in question.
The fallacy of composition is the inference from (a) to (b) but it
need not hold if members of the team cannot work cooperatively with
each other. The reverse inference from (b) to (a)--the fallacy of
division--may also fail if some essential members of the team
have a supportive or administrative role rather than a research
role.



5. The fallacy of begging the question (*petitio principii*)
can occur in a number of ways. One of them is nicely illustrated with
Whately's (1875 III SS13) example: "to allow everyman
an unbounded freedom of speech must always be, on the whole,
advantageous to the State; for it is highly conducive to the interest
of the Community, that each individual should enjoy a liberty
perfectly unlimited, of expressing his sentiments." This argument begs
the question because the premise and conclusion are the very same
proposition, albeit expressed in different words. It is a disguised
instance of repetition which gives no reason for its apparent
conclusion.



Another version of begging the question can occur in contexts of
argumentation where there are unsettled questions about key terms.
Suppose, for example, that everyone agrees that to murder someone
requires doing something that is wrong, but not everyone agrees that
capital punishment is a form of 'murder'; some think it is
justified killing. Then, should an arguer gives this argument:



> 
>  Capital punishment requires an act of murdering human beings.  
> 
>  So, capital punishment is wrong.



one could say that this is question-begging because in this context of
argumentation, the arguer is smuggling in as settled a question that
remains open. That is, if the premise is accepted without further
justification, the arguer is assuming the answer to a controversial
question without argument.



Neither of these versions of begging the question are faulted for
their invalidity, so they are not charged with being non-sequitors
like most of the core fallacies; they are, however, attempted proofs
that do not transparently display their weakness. This consideration,
plus its ancient lineage back to Aristotle, might explain begging the
question's persistent inclusion among fallacies. But, given our
allegiance to the modern conception of logic as being solely concerned
with the following-from relation, forms of begging the question should
be thought of as epistemic rather than logical fallacies.



Some versions of begging the question are more involved and are called
circular reasoning. They include more than one inference. Descartes
illustrated this kind of fallacy with the example of our belief in the
Bible being justified because it is the word of God, and our belief in
God's existence being justified because it is written in the 
Bible.[2]
 The two propositions lead back and forth to each other, in a circle,
each having only the support of the other.



6. The fallacy known as *complex question* or *many
questions* is usually explained as a fallacy associated with
questioning. For example, in a context where a Yes or No answer must
be given, the question, "Are you still a member of the Ku Klux
Klan?" is a fallacy because either response implies that one has
in the past been a member of the Klan, a proposition that may not have
been established as true. Some say that this kind of mistake is not
really a fallacy because to ask a question is not to make an
argument.



7. There are a number of fallacies associated with causation, the most
frequently discussed is *post hoc ergo propter hoc*, (after
this, therefore because of this). This fallacy ascribes a causal
relationship between two states or events on the basis of temporal
succession. For example,



Unemployment decreased in the fourth quarter because the government
eliminated the gasoline tax in the second quarter.



The decrease in unemployment that took place after the elimination of
the tax may have been due to other causes; perhaps new industrial
machinery or increased international demand for products. Other
fallacies involve confusing the cause and the effect, and overlooking
the possibility that two events are not directly related to each other
but are both the effect of a third factor, a common cause. These
fallacies are perhaps better understood as faults of explanation than
faults of arguments.



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
that 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.



9. The *ad verecundiam* fallacy concerns appeals to authority
or expertise. Fundamentally, the fallacy involves accepting as
evidence for a proposition the pronouncement of someone who is taken
to be an authority but is not really an authority. This can happen
when non-experts parade as experts in fields in which they have no
special competence--when, for example, celebrities endorse
commercial products or social movements. Similarly, when there is
controversy, and authorities are divided, it is an error to base
one's view on the authority of just some of them. (See also 2.4
below.)



10. The fallacy *ad populum* is similar to the *ad
verecundiam*, the difference being that the source appealed to is
popular opinion, or common knowledge, rather than a specified
authority. So, for example:



These days everyone (except you) has a car and knows how to drive;
  

So, you too should have a car and know how to drive.



Often in arguments like this the premises aren't true, but even
if they are generally true they may provide only scant support for
their conclusions because that something is widely practised or
believed is not compelling evidence that it is true or that it should
be done. There are few subjects on which the general public can be
said to hold authoritative opinions. Another version of the *ad
populum* fallacy is known as "playing to the gallery"
in which a speaker seeks acceptance for his view by arousing relevant
prejudices and emotions in his audience in lieu of presenting it with
good evidence.



11. The *ad baculum* fallacy is one of the most controversial
because it is hard to see that it is a fallacy or even that it
involves bad reasoning. *Ad baculum* means "appeal to the
stick" and is generally taken to involve a threat of injury of
harm to the person addressed. So, for example,



If you don't join our demonstration against the expansion of the
park, we will evict you from your apartment;
  

So, you should join our demonstration against the expansion of the
park.



Such threats do give us reasons to act and, unpleasant as the
interlocutor may be, there seems to be no fallacy here. In labour
disputes, and perhaps in international relations, using threats such
as going on strike, or cutting off trade routes, are not normally
considered fallacies, even though they do involve intimidation and the
threat of harm. However, if we change to doxastic considerations, then
the argument that you should *believe* that candidate \(X\) is
the one best suited for public office because if you do not believe
this you will be evicted from your apartment, certainly is a good
instance of irrelevant evidence.



12. The fallacy *ad misericordiam* is a companion to the *ad
baculum* fallacy: it occurs not when threats are out of place but
when appeals for sympathy or pity are mistakenly thought to be
evidence. To what extent our sympathy for others should influence our
actions depends on many factors, including circumstances and our
ethical views. However, sympathy alone is generally not evidence for
believing any proposition. Hence,



You should believe that he is not guilty of embezzling those
paintings; think of how much his family suffered during the
Depression.



*Ad misericordiam* arguments, like *ad baculum*
arguments, have their natural home in practical reasoning; it is when
they are used in theoretical (doxastic) argumentation that the
possibility of fallacy is more likely.



13. The *ad hominem* fallacy involves bringing negative aspects
of an arguer, or their situation, to bear on the view they are
advancing. There are three commonly recognized versions of the
fallacy. The abusive *ad hominem* fallacy involves saying that
someone's view should not be accepted because they have some
unfavorable property.



Thompson's proposal for the wetlands may safely be rejected
because last year she was arrested for hunting without a license.



The hunter Thompson, although she broke the law, may nevertheless have
a very good plan for the wetlands.



Another, more subtle version of the fallacy is the circumstantial
*ad hominem* in which, given the circumstances in which the
arguer finds him or herself, it is alleged that their position is
supported by self-interest rather than by good evidence. Hence, the
scientific studies produced by industrialists to show that the levels
of pollution at their factories are within the law may be undeservedly
rejected because they are thought to be self-serving. Yet it is
possible that the studies are sound: just because what someone says is
in their self-interest, does not mean it should be rejected.



The third version of the *ad hominem* fallacy is the *tu
quoque*. It involves not accepting a view or a recommendation
because the espouser him- or herself does not follow it. Thus, if our
neighbor advises us to exercise regularly and we reject her advice on
the basis that she does not exercise regularly, we commit the *tu
quoque* fallacy: the value of advice is not wholly dependent on
the integrity of the advisor.



We may finish our survey of the core fallacies by considering just two
more.



14. The fallacy of *faulty analogy* occurs when analogies are
used as arguments or explanations and the similarities between the two
things compared are too remote to support the conclusion.



If a child gets a new toy he or she will want to play with it;
  

So, if a nation gets new weapons, it will want to use them.



In this example (due to Churchill 1986, 349) there is a great
difference between using (playing with) toys and using (discharging)
weapons. The former is done for amusement, the latter is done to
inflict harm on others. Playing with toys is a benign activity that
requires little justification; using weapons against others nations is
something that is usually only done after extensive deliberation and
as a last resort. Hence, there is too much of a difference between
using toys and using weapons to conclude that a nation, if it acquires
weapons, will want to use them as readily as children will want to
play with their toys.



15. The fallacy of the *slippery slope* generally takes the
form that from a given starting point one can by a series of
incremental inferences arrive at an undesirable conclusion, and
because of this unwanted result, the initial starting point should be
rejected. The kinds of inferences involved in the step-by-step
argument can be causal, as in:



You have decided not to go to college;
  

If you don't go to college, you won't get a degree;
  

If you don't get a degree, you won't get a good job;
  

If you don't get a good job, you won't be able to enjoy
life;
  

But you should be able to enjoy life;
  

So, you should go to college.



The weakness in this argument, the reason why it is a fallacy, lies in
the second and third causal claims. The series of small steps that
lead from an acceptable starting point to an unacceptable conclusion
may also depend on vague terms rather than causal relations. Lack of
clear boundaries is what enables the puzzling slippery slope arguments
known as "the beard" and "the heap." In the
former, a person with a full beard eventually becomes beardless as
hairs of the beard are removed one-by-one; but because the term
'beard' is vague it is unclear at which intermediate point
we are to say that the man is now beardless. Hence, at each step in
the argument until the final hair-plucking, we should continue to
conclude that the man is bearded. In the second case, because
'heap' is vague, it is unclear at what point piling
scattered stones together makes them a heap of stones: if it is not a
heap to begin with, adding one more stone will not make it a heap,
etc. In both these cases apparently good reasoning leads to a false
conclusion.



Many other fallacies have been named and discussed, some of them quite
different from the ones mentioned above, others interesting and novel
variations of the above. Some of these will be mentioned in the review
of historical and contemporary sources that follows.


## 2. History of Fallacy Theory


### 2.1 Aristotle



The history of the study of fallacies begins with Aristotle's
work, *On Sophistical Refutations*. It is among his earlier
writings and the work appears to be a continuation of the
*Topics*, his treatise on dialectical argumentation. Although
his most extensive and theoretically detailed discussion of fallacies
is in the *Sophistical Refutations*, Aristotle also discusses
fallacies in the *Prior Analytics* and *On Rhetoric*.
Here we will concentrate on summarizing the account given in the
*Sophistical Refutations*. In that work, four things are worth
noting: (a) the different conceptions of fallacy; (b) the basic
concepts used to explain fallacies; (c) Aristotle's explanation
of why fallacies can be deceptive; and (d) his enumeration and
classification of fallacies.


#### 2.1.1 Definitions



At the beginning of *Topics* (I, i), Aristotle distinguishes
several kinds of deductions (syllogisms). They are distinguished first
on the basis of the status of their premises. (1) Those that begin
from true and primary premises, or are owed to such, are
demonstrations. (2) Those which have dialectical
premises--propositions acceptable to most people, or to the
wise--are dialectical deductions. (3) Deductions that start from
premises which only appear to be dialectical, are fallacious
deductions because of their starting points, as are (4) those
"deductions" that do have dialectical premises but do not
really necessitate their conclusions. Other fallacies mentioned and
associated with demonstrations are (5) those which only appear to
start from what is true and primary (*Top*., I, i 101a5). What
this classification leaves out are (6) the arguments that do start
from true and primary premises but then fail to necessitate their
conclusions; two of these, begging the question and non-cause are
discussed in *Prior Analytics* (II, 16, 17). It is the
"fallacious deductions" characterized in (4), however,
that come closest to the focus of the *Sophistical
Refutations*. Nevertheless, in many of the examples given what
stands out is that the premises are given as answers in dialogue and
are to be maintained by the answerer, not necessarily that they are
dialectical in the sense of being common opinions. This variation on
dialectical deductions Aristotle calls examination arguments
(*SR* 2 165b4).


#### 2.1.2 The basic concepts



There are three closely related concepts needed to understand
sophistical refutations. By a *deduction* (a
 syllogism[3])
 Aristotle meant an argument which satisfies three conditions: it
"is based on certain statements made in such a way as
necessarily to cause the assertion of things other than those
statements and as a result of those statements" (*SR* 1
165a1-2). Thus an argument may fail to be a syllogism in three
different ways. The premises may fail to necessitate the conclusion,
the conclusion may be the same as one of the premises, and the
conclusion may not be caused by (grounded in) the premises. The
concept of a *proof* underlying *Sophistical
Refutations* is similar to what is demanded of demonstrative
knowledge in *Posterior Analytics* (I ii 71b20), viz., that the
premises must be "true, primary, immediate, better known than,
prior to, and causative of the conclusion," except that the
first three conditions do not apply to deductions in which the
premises are obtained through questioning. A *refutation*,
Aristotle says, is "a proof of the contradictory"
(*SR* 6, 168a37)--a proof of the proposition which is the
contradictory of the thesis maintained by the answerer. In a context
of someone, *S*, maintaining a thesis, *T*, a
dialectical refutation will consist in asking questions of *S*,
and then taking *S*'s answers and using them as the
premises of a proof via a deduction of *not-T*: this will be a
refutation of *T* relative to the answerer (*SR* 8
170a13). The concept of contradiction can be found in
*Categories*: it is those contraries which are related such
that "one opposite needs must be true, while the other must
always be false" (13b2-3). A refutation will be
sophistical if either the proof is only an apparent proof or the
contradiction is only an apparent contradiction. Either way, according
to Aristotle, there is a fallacy. Hence, the opening of his treatise:
"Let us now treat of sophistical refutations, that is, arguments
which appear to be refutations but are really fallacies and not
refutations" (*SR* 1 164a20).


#### 2.1.3 The appearance condition



Aristotle observed that "reasoning and refutation are sometimes
real and sometimes not, but appear to be real owing to men's
inexperience; for the inexperienced are like those who view things
from a distance" (*SR*, 1 164b25). The ideas here are
first that there are arguments that appear to be better than they
really are; and second that people inexperienced in arguments may
mistake the appearance for the reality and thus be taken in by a bad
argument or refutation. Apparent refutations are primarily explained
in terms of apparent deductions: thus, with one exception,
Aristotle's fallacies are in the main a catalogue of bad
deductions that appear to be good deductions. The exception is
*ignoratio elenchi* in which, in one of its guises, the
deduction contains no fallacy but the conclusion proved only appears
to contradict the answerer's thesis.



Aristotle devotes considerable space to explaining how the appearance
condition may arise. At the outset he mentions the argument that turns
upon names (*SR* 1 165a6), saying that it is the most prolific
and usual explanation: because there are more things than names, some
names will have to denote more than one thing, thereby creating the
possibility of ambiguous terms and expressions. That the ambiguous use
of a term goes unnoticed allows the illusion that an argument is a
real deduction. The explanation of how the false appearance can arise
is in the similarity of words or expressions with different meanings,
and the smallness of differences in meaning between some expressions
(*SR* 7 169a23-169b17).


#### 2.1.4 List and classification



Aristotle discusses thirteen ways in which refutations can be
sophistical and divides them into two groups. The first group,
introduced in Chapter 4 of *On Sophistical Refutations*,
includes those Aristotle considers dependent on language (*in
dictione*), and the second group, introduced in Chapter 5,
includes those characterized as not being dependent on language
(*extra dictionem*). Chapter 6 reviews all the fallacies from
the view point of failed refutations, and Chapter 7 explains how the
appearance of correctness is made possible for each fallacy. Chapters
19-30 advise answerers on how to avoid being taken in by
sophistical refutations.



The fallacies dependent on language are equivocation, amphiboly,
combination of words, division of words, accent and form of
expression. Of these the first two have survived pretty much as
Aristotle thought of them. Equivocation results from the exploitation
of a term's ambiguity and amphiboly comes about through
indefinite grammatical structure. 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.
Aristotle's fallacies are the combinations and divisions of
words which alter meanings, e.g., "walk while sitting" vs.
"walk-while-sitting," (i.e., to have the ability to walk
while seated vs. being able to walk and sit at the same time). 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. Double meaning is
also possible with those words whose meanings depend on how they are
pronounced, this is the fallacy of accent, but there were no accents
in written Greek in Aristotle's day; accordingly, this fallacy
would be more likely in written work. What Aristotle had in mind is
something similar to the double meanings that can be given to
'unionized' and 'invalid' depending on how
they are pronounced. 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. Aristotle's example is the word
'flourishing' which may appear to be a verb because of its
'ing' ending (as in 'cutting' or
'running') and so belongs to the category of actions,
whereas it really belongs in the category of quality. 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.



The fallacy of accident is the most elusive of the fallacies on
Aristotle's list. It turns on his distinction between two kinds
of predication, unique properties and accidents (*Top*. I 5).
The fallacy is defined as occurring when "it is claimed that
some attribute belongs similarly to the thing and to its
accident" (*SR* 5 166b28). What belongs to a thing are
its unique properties which are counterpredicable (Smith 1997, 60),
i.e., if \(A\) is an attribute of \(B\), \(B\) is an attribute of
\(A\). 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 2001, ch. 7).



Aristotle considers the fallacy of consequent to be a special case of
the fallacy of accident, observing that consequence is not
convertible, i.e., "if \(A\) is, \(B\) necessarily is, men also
fancy that, if \(B\) is, \(A\) necessarily is" (*SR* 5
169b3). One of Aristotle's examples is that it does not follow
that "a man who is hot must be in a fever because a man who is
in a fever is hot" (*SR* 5 169b19). 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. Spruce trees, for example, are green with
respect to their foliage (they are 'green' with
qualification); it would be a mistake to infer that they are green
absolutely because they have brown trunks and branches. 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, 13). 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 168b23).



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 2001).



Aristotle's fallacy of many questions occurs when two questions
are asked as if they are one proposition. A proposition is "a
single predication about a single subject" (*SR* 6
169a8). 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 2000,
156-59). Despite its name, this fallacy consists in the ensuing
deduction, not in the question which merely triggers the fallacy.



On one interpretation *ignoratio elenchi* is considered to be
Aristotle's thirteenth fallacy, in which an otherwise successful
deduction fails to end with the required contradictory of the
answerer's thesis. 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. On
another reading, *ignoratio elenchi* is not a separate fallacy
but an alternative to the language dependent / language independent
way of classifying the other twelve fallacies: they all fail to meet,
in one way or another, the requirements of a sound refutation.



> 
> [A] refutation is a contradiction of one and the same predicate, not
> of a name but of a thing, and not of a synonymous name but of an
> identical name, based on the given premises and following necessarily
> from them (the original point at issue not being included) in the same
> respect, manner and time. (*SR* 5 167a23-27)
> 



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.


#### 2.1.5 Different interpretations



I have given only the briefest possible explanation of
Aristotle's fallacies. To really understand them a much longer
engagement with the original text and the secondary sources is
necessary. The second chapter of Hamblin's (1970) book is a
useful introduction to the *Sophistical Refutations*, and a
defence of the dialectical nature of the fallacies. Hamblin thinks
that a dialectical framework is indispensable for an understanding of
Aristotle's fallacies and that part of the poverty of
contemporary accounts of fallacies is due to a failure to understand
their assumed dialectical setting. This approach to the fallacies is
continued in contemporary research by some argumentation theorists,
most notably Douglas Walton (1995) who also follows Aristotle in
recognizing a number of different kinds of dialogues in which
argumentation can occur; Frans van Eemeren and Rob Grootendorst (2004)
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
1987; Bachman 1995.) According to Hintikka (1997) it is an outright
mistake to think of Aristotle's fallacies primarily as mistaken
inferences, either deductive or inductive. A non-dialogue oriented
interpretation of Aristotle fallacies is found in Woods and Hansen
(1997 and 2001) who argue that the fallacies (apparent deductions) are
basic to apparent refutations, and that Aristotle's interest in
the fallacies extended beyond dialectical contests, as is shown by his
interest in them in the *Prior Analytics* and the
*Rhetoric* (II 24). What gives unity to Aristotle's
different fallacies on this view is not a dialogue structure but
rather their dependence on the concepts of deduction and proof. The
most thorough recent study of these questions is in Schreiber (2003),
who emphasizes Aristotle's concern with resolving (exposing)
fallacies and argues that it is Aristotelian epistemology and
metaphysics that is needed for a full understanding of the fallacies
in the *Sophistical Refutations*.


### 2.2 Bacon



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 (1620, 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.
The idols of the theatre are the acquired false philosophies, systems
and methods, both new and ancient, that rule men's minds. These
three idols all fall into the category of explanations of why we may
misperceive the world. A fourth of Bacon's idols, the idol of
the market place, is the one that comes closest to the Aristotelian
tradition as it points to language as the source of our mistaken
ideas: "words plainly force and overrule the understanding, and
throw all into confusion, and lead men away into numberless empty
controversies and idle fancies" (1620, aphorism 43). Although
Bacon identifies no particular fallacies in Aristotle's sense,
he opens the door to the possibility that there may be false
assumptions associated with the investigation of the natural 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.


### 2.3 Arnauld and Nicole



Antoine Arnauld and Pierre Nicole were the authors of *Logic, or
the Art of Thinking* (1662), commonly known as the Port-Royal
Logic. According to Benson Mates (1965, 214) it "is an
outstanding early example of the 'how to think straight'
genre." The work includes chapters on sophisms, with the
justification that "examples of mistakes to be avoided are often
more striking than the examples to be imitated" (Bk. III, xix).
The Port-Royal Logic does not continue Aristotle's distinction
between fallacies that are dependent on language and those that are
not; instead there is a division between sophisms associated with
scientific subjects (ibid.)--these are nearly all from the
*Sophistical Refutations*--and those committed in everyday
life and ordinary discourse (Bk III, xx). The division is not
exclusive, with some of the sophisms fitting both classes.



The Port-Royal Logic includes eight of Aristotle's original
thirteen fallacies, several of them modified to fit the bent to
natural philosophy rather than dialectical argumentation. 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. Also identified as a common fallacy of the human mind is
*post hoc, ergo propter hoc*: "This happened following a
certain thing, hence that thing must be its cause" (Bk. 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. *Ignoratio elenchi* retains
its dialogical setting but is extended beyond the mere failure to
contradict a thesis, "to attribut[ing] to our adversaries
something remote from their views to gain an advantage over them, or
to impute to them consequences we imagine can be drawn from their
doctrines, although they disavow and deny them" (Bk. 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 7), and towards the end of their discussion they add the
sophism of manner, cautioning that "grace, fluency, seriousness,
moderation and gentleness" is not necessarily a mark of truth
(Bk. III, xx 8). The authors seem to have the rhetorical flourishes of
royal courtiers especially in mind.


### 2.4 Locke



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. In *An Essay Concerning Human
Understanding* (1690), he identified three kinds of arguments, the
*ad verecundiam*, *ad ignorantiam*, and *ad
hominem* arguments, each of which he contrasted with *ad
judicium* arguments which are arguments based on "the
foundations of knowledge and probability" and are reliable
routes to truth and knowledge. Locke did not speak of
*ad*-arguments as fallacies--that was left to others to do
later--but rather as kinds of arguments "that men, in their
reasoning with others, do ordinarily make use of to prevail on their
assent; or at least so to awe them as to silence their
opposition." (Bk IV, xvii, 19-22).



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. When it is a fallacy it is either on
the ground that authorities (experts) are fallible or for the reason
that appealing to authority is an abandonment of an individual's
epistemic responsibility. 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. In addition to epistemic and legal (command) authority there is
also what might be called social authority, demanding respect and
deference from others due to one's higher social standing,
something much more a part of seventeenth-century society than it is a
part of ours. The language that Locke used in connection with the
*ad verecundiam*, words like 'eminency',
'dignity', 'breach of modesty', and
'having too much pride' suggests that what he had in mind
was the kind of authority that demands respect for the social standing
of sources rather than for their expertise; hence, by this kind of
authority a person could be led to accept a conclusion because of
their modesty or shame, more so than for the value of the argument
(see Goodwin 1998, Hansen 2006). Hence, we understand Locke better
when we translate *ad verecundiam* literally, as "appeal
to modesty."



The argumentum *ad hominem*, as Locke defined it, has
subsequently developed into three different fallacies. His original
description was that it was a way "to press a man with
consequences drawn from his own principles or concessions." That
is, to argue that an opponent's view is inconsistent, logically
or pragmatically, with other things he has said or to which he is
committed. Locke's observation was that such arguments do not
advance us towards truth, but that they can serve to promote agreement
or stall disagreement. To argue that way is not a fallacy but an
acceptable mode of argumentation. Henry Johnstone (1952) thought it
captured the essential character of philosophical argumentation. The
modern descendants of the Lockean *ad hominem* are the abusive
*ad hominem* which is an argument to the effect that a position
should not be accepted because of some telling negative property of
its espouser; the circumstantial *ad hominem*, an argument to
the effect that someone's position should be rejected because
circumstances suggest that their view is the result of self-interested
bias; and finally, the *tu quoque ad hominem* argument which
attempts to deflect a criticism by pointing out that it applies
equally to the accuser. 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*.



*Ad ignorantiam* translates as "appeal to
ignorance." Locke's characterization of this kind of
argument is that it demands "the adversary to admit what they
allege as a proof, or to assign a better." The ignorance in
question is comparative, it is not that the opponent has no evidence,
it is that s/he has no better evidence. However, the inability of an
opponent to produce a better argument is not sufficient reason to
think the proponent's argument must be accepted. 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,
1995).



The introduction and discussion of the *ad*-arguments appears
almost as an afterthought in Locke's *Essay*. It is found
at the end of the chapter, "Of Reason," in which Locke
devotes considerable effort to criticizing syllogistic logic.
Reasoning by syllogisms, he maintained, was neither necessary nor
useful for knowledge. Locke clearly thought that the three
*ad*-arguments were inferior to *ad judicium* arguments,
but he never used the term 'fallacy' in connection with
them, although he did use it in connection with errors of syllogistic
reasoning.



Was Locke the first to discuss these kinds of arguments? Hamblin
(1970, 161-62) and Nuchelmans (1993) trace the idea of *ad
hominem* arguments back to Aristotle, and Locke's remark
that the name *argumentum ad hominem* was already known has
been investigated by Finocchiaro (1974) who finds the term and the
argument kind in Galileo's writings more than a half-century
before the *Essay Concerning Human Understanding*. And Arnauld
and Nicole's discussion of the sophism of authority, that
"people speak the truth because they are of noble birth or
wealthy or in high office," which seems to be part of
Locke's *ad verecundiam*, was most likely known to him.
Subsequently more *ad*-arguments were added to the four that
Locke identified (see Watts, and Copi, below).


### 2.5 Watts



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 *non causa 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).


### 2.6 Bentham



Jeremy Bentham's *Handbook of Political Fallacies* (1824)
was written in the years leading up to the first Reform Bill (1832).
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 (1824, 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). Most of Bentham's fallacies have not
become staples of fallacy theory but many of them show interesting
insights into the motives and techniques of debaters (see e.g.,
Rudanko's (2005, 2009) analyses of the *ad
socordiam*).



Bentham's *Handbook* has not taken a central place in the
history of fallacy studies (Hamblin 1970, 165-69); nevertheless,
it is historically interesting in several respects. 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. Fallacies of authority in
political debate occur when authority "is employed in the place
of such relevant arguments as might have been brought forward"
(1824, 25). Bentham's fear is that debaters will resort to
"the authority" of traditional beliefs and principles
instead of considering the advantages of the reform measures under
discussion.



Under the heading "fallacies of danger" Bentham named a
number of what he called vituperative fallacies--imputations of
bad character, bad motive, inconsistency, and suspicious
connections--which have as their common characteristic,
"the endeavour to draw aside attention from the *measure*
to the *man*, in such a way as to cause the latter's
badness to be imputed to the measure he supports, or his goodness to
his opposition" (1824, 83). 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
1997).


### 2.7 Whately



Book III of Richard Whately's *Elements of Logic* (1826)
is devoted to giving an account of fallacies based on "logical
principles,". 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).



By 'fallacy' Whately meant "any unsound mode of
arguing, which appears to demand our conviction, and to be decisive of
the question at hand, when in fairness it is not"' (Bk.
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. III, SS2); they include,
among others, the fallacies of ambiguity, and division and
composition. The non-logical, material fallacies are also divided into
two classes: fallacies with premises 'unduly assumed,' and
fallacies of irrelevant conclusions. 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. Whately's version of
the *ad hominem* argument resembles Locke's in that it is
an *ex concessis* kind of argument: one that depends on the
concessions of the person with whom one is arguing. From the
concessions, one might prove that one's opponent is
'committed to *p,*' but an attempt to make it seem
as if this constitutes a proof of the absolute (non-relative)
proposition '*p*' would be a fallacy. 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 2.1.1 above).
Whately's creation of the category of non-logical fallacies
solved the problem of what to do with begging the question which is
not an invalid form of argument, and it also created a place in
fallacy taxonomy for the *ad*-fallacies.


### 2.8 Mill



John Stuart Mill's contribution to the study of fallacies is
found in Book V of his comprehensive *A System of Logic,
Ratiocinative and Inductive*, first published in 1843. It stands
out most strikingly for placing the study of fallacies within his
framework of inductive reasoning, a direct rejection of
Whately's deductivist approach to reasoning and fallacies. 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.
"A catalogue of the varieties of evidence which are not real
evidence," he wrote, "is an enumeration of
fallacies" (1891, Bk.V iii SS1).



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. But also included are the conversion of universal
affirmatives and particular negatives ("All PS" does not
follow from "All SP," and "Some P not S" does
not follow from "Some S not P"). Also included in this
category is the *secundum quid* fallacy.



The other sub-class of fallacies distinctly conceived bring out what
is distinctive about Mill's work on the fallacies: that it is
the first extensive attempt to deal with fallacies of induction. He
divided inductive fallacies into two further groups: fallacies of
observation (V, iv) and fallacies of generalization (Bk. V, v).
Fallacies of observation can occur either negatively or positively.
Their negative occurrence consists in non-observation in which one has
overlooked negatively relevant evidence. This is similar to what the
Port-Royal Logic considered a faulty enumeration, and one of
Mill's examples is the continued faith that farmers put in the
weather forecasts found in almanacs despite their long history of
false predictions. Observation fallacies occur positively when the
mistake is based on something that is seen wrongly, i.e., taken to be
something that it is not. 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). Analogical arguments
are identified as a false basis for generalizations; they are
"at best only admissible as an inconclusive presumption, where
real proof is unattainable" (Bk. 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. Among
Mill's examples of *a priori* fallacies are metaphysical
assumptions such as that distinctions of language correspond to
distinctions in nature, and that objects cannot affect each other at a
distance. 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.



*A System of Logic* is the most extensive work on fallacies
since Aristotle's *Sophistical Refutations*. Mill's
examples are taken from a wide range of examples in science, politics,
economics, religion and philosophy. His classificatory scheme is
original and comprehensive. Frederick Rosen (2006) argues that
Mill's pre-occupation with the detection and prevention of
fallacies is part of what motivates the celebrated second chapter of
*On Liberty*. Despite these considerations, the *Logic*
is not much referenced by fallacy theorists.


### 2.9 Copi



Irving Copi's *Introduction to Logic*--an
influential text book from the mid-twentieth century--defines a
fallacy as "a form of argument that seems to be correct but
which proves, upon examination, not to be so." (1961, 52) The
term 'correct' is sufficiently broad to allow for both
deductive invalidity, inductive weakness, as well as some other kinds
of argument failure. 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.



The first division in Copi's classification is between formal
and informal fallacies. Formal fallacies are invalid inferences which
"bear a superficial resemblance" to valid forms of
inference, so these we may think of as deductive fallacies. 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. One division of
informal fallacies is the fallacies of relevance which are
"errors in reasoning into which we may fall because of
carelessness and inattention to our subject matter" (1961, 53).
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.



It seems that Copi took Whately's category of semi-logical
fallacies and moved them under a new heading of 'informal
fallacies,' presumably for the reason that extra-logical
knowledge is needed to uncover their invalidity. 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*).[5]
 Copi's classification, unlike Whately's which sought to
make a distinction on logical grounds, may be seen as based on three
ways that fallacies resemble good arguments: formal fallacies have
invalid forms that resemble valid forms, fallacies of ambiguity
resemble good arguments through the ambiguity of terms, and fallacies
of relevance exploit psychological (non-logical) associations. Hence,
we may think of Copi's divisions as between logical, semantic
and psychological fallacies.



Copi's treatment of the fallacies is a fair overview of the
traditional list of fallacies, albeit he did not pretend to do any
more than give an introduction to existing fallacy-lore for beginning
logic students. Hamblin (1970, ch. 1) criticized Copi's work,
along with that of several others, and gave it the pejorative name,
"the standard treatment of fallacies." His criticisms rang
true with many of his readers, thereby provoking contempt for the
traditional treatment of fallacies as well as stimulating research in
what we may call the new, or post-Hamblin, era, of fallacy studies.
Let us next consider some of these developments.


## 3. New approaches to fallacies


### 3.1 Renewed interest



A common complaint since Whately's *Elements of Logic* is
that our theory and teaching of fallacies are in want of
improvement--he thought they should be put on a more logical
footing to overcome the loose and vague treatments others had
proffered.



> 
> It is on Logical principles therefore that I propose to discuss the
> subject of Fallacies. ... the generality of Logical writers have
> usually followed so opposite a plan. Whenever they have to treat of
> anything that is beyond the mere elements of Logic, they totally lay
> aside all reference to the principles they have been occupied in
> establishing and explaining, and have recourse to a loose, vague, and
> popular kind of language ... [which is] ... strangely
> incongruous in a professional Logical treatise. (1875, III, intro.)
> 



Charles Hamblin's 1970 book, *Fallacies*, revives
Whately's complaint. 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.
The work opens with a critique of the standard treatment of fallacies
as it was found in mid-twentieth century textbooks; then, in
subsequent chapters, it takes a historical turn reviewing
Aristotle's approach to fallacies and exploring the tradition it
fostered (as in the previous section of this entry). Other
historically-oriented chapters include one on the Indian tradition,
and one on formal fallacies. Hamblin's more positive
contributions to fallacy studies are concentrated in the book's
later chapters on the concept of argument, formal dialectics, and
equivocation.



What Hamblin meant by "the standard treatment of
fallacies" was:



> 
> The typical or average account as it appears in the typical short
> chapter or appendix of the average modern textbook. And what we find
> in most cases, I think it should be admitted, is as debased, worn-out
> and dogmatic a treatment as could be imagined--incredibly
> tradition bound, yet lacking in logic and in historical sense alike,
> and almost without connection to anything else in modern Logic at all.
> (1970, 12)
> 



Let us consider what came before Hamblin as the traditional approach
to fallacies and what comes after him as new approaches. The new
approaches (since the 1970's) show a concern to overcome
Hamblin's criticisms, and they also vie with each to produce the
most defensible alternative to the traditional approach. One thing
that nearly all the new approaches have in common is that they reject
what Hamblin presents as the nearly universally accepted definition of
"fallacy" as an argument "that *seems to be
valid* but *is not* so" (1970, 12). Although this
definition of fallacy is not nearly as widely accepted as Hamblin
intimated (see Hansen 2002), others have taken to calling it
"the standard definition of fallacies" and for convenience
we can refer to it as SDF. 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.


### 3.2 Doubts about fallacies



Maurice Finocchiaro continued Hamblin's criticism of the modern
textbook treatment of fallacies, observing that they contain very few
examples of actual fallacies, leading him to doubt the validity of
'fallacy' as a genuine logical category. Although he
allows that errors in reasoning are common in real life, he thinks
that "types of logically incorrect
arguments"--fallacies--are probably not common (1981,
113). 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* (1987, 133). He further distances himself from SDF
by not considering the appearance condition.



Finocchiaro distinguishes six ways in which arguments can be
fallacious. (1) *Formal fallaciousness* is simply the case
where the conclusion does not follow validly from the premises; this
type of error can be demonstrated by producing a suitable analogous
counter-example in which the premises are true and the conclusion is
false. (2) *Explanatory fallaciousness* occurs when a specified
conclusion follows with no more certainty from the given premises than
does a rival conclusion; it occurs most often in the context of
proposing explanatory hypotheses. (3) *Presuppositional
fallaciousness* occurs in those cases where an argument depends on
a false presupposition; this kind of fallaciousness is demonstrated by
making a sound argument showing the presupposition to be false. (4)
*Positive fallaciousness* occurs when the given premises,
complemented by other propositions taken as true, are shown to support
a conclusion inconsistent with the given conclusion. (5)
*Semantical fallaciousness* results from the ambiguity of
terms; the conclusion will follow if the sense given to the term in
the premises makes the premises false, but if the other sense is
ascribed to the term, making the premises true, the conclusion does
not follow (it becomes an instance of formal fallaciousness). (6)
Finally, Finocchiaro singles out *persuasive fallaciousness*,
in which the conclusion does not follow from the premises because it
is the same as one of the premises. As a test of completeness of this
six-fold division of fallaciousness, Finocchiaro (1987) 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 (1981) 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
(1981, 164). 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. Since upholders of SDF maintain that
fallacies are invalid arguments, Massey's asymmetry thesis has
the consequence that no argument can be convicted of being a fallacy
on logical
 grounds.[6]


### 3.3 The informal logic approach to fallacies



The informal logic approach to fallacies is taken in Johnson and
Blair's *Logical Self-Defence*, a textbook first
published in 1977. It was prompted in part by Hamblin's
indictment of the standard treatment and it further develops an
initiative taken by Kahane (1971) to develop university courses that
were geared to everyday reasoning. Johnson and Blair's emphasis
is on arming students to defend themselves against fallacies in
everyday discourse, and a fundamental innovation is in their
conception of a good argument. 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, 2007). 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.



The three criteria of a cogent argument, individually necessary and
jointly sufficient, lead to a conception of fallacy as "any
argument that violates one of the criteria of good argument ...
and is committed frequently in argumentative discourse" (1993,
317-18). 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 (1987) 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. The category of fallacies with problematic
premises (reminiscent of Whately's "premises unduly
assumed") shows a concern with argument evaluation over and
beyond logical or inference evaluation, drawing the informal logic
approach away from purely logical concerns towards an epistemic
conception of fallacies. Having both sufficiency and relevance as
criteria (instead of the single validity criterion) has the benefit of
allowing the making of nuanced judgments about the level of premise
support: for example, we might say that an argument's premises,
although insufficient, are nevertheless positively relevant to the
conclusion. 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. The informal
logicians' conception of fallacies is meant to be broader and
more suitable to natural language argumentation than would be a
conception tied only to deductive invalidity.



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.g., accident, composition and division) and the
ones retained find themselves in new categories: begging the question
and ambiguity are together under the heading of Problematic Premise;
appeals to authority and popularity are placed under the heading of
Hasty Conclusion fallacies; *ad hominem* is among the fallacies
that belong in the third category, Fallacies of Irrelevant Reason.
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. Johnson and Blair's approach is responsive to
this problem in that it allows the names of the classes of fallacies
-- 'unacceptable premise,' 'irrelevant
reason' and 'hasty conclusion' -- to stand for
fallacies themselves, fallacies broad-in-scope; i.e., to serve
"both as general principles of organization, and as back-ups to
fill in any gaps between specific labels belonging within each
genus" (1993, 52). Hence, any violation of one of the criteria
of a cogent argument can be considered a fallacy.



In addition to this alternative theoretical approach to fallacies
built on the three criteria of a cogent argument--an approach
also taken up by
 others[7]--informal
 logic's contribution to fallacy studies lies in its attempts to
provide better analyses of fallacies, a programme pursued by a large
number of researchers, including Govier (1982) on the slippery slope,
Wreen (1989) on the *ad baculum*, Walton (1991) on begging the
question, Brinton (1995) on the *ad hominem*, Freeman (1995) on
the appeal to popularity, and Pinto (1995) on *post hoc ergo
propter hoc*.


### 3.4 The formal approach to informal fallacies



John Woods also despairs of the standard treatment but he sees in it
something of importance; namely that the fallacies most often reviewed
in introductory level logic textbooks "are a kind of caricature
of their associated improprieties, which lie deeply imbedded in human
practice" (Woods 1992, 25). 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
(1989), 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 verecundiam*, and
dialectical game theory for begging the question and many questions.
Woods (1992, 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.



Woods (2013) has continued his research on fallacies, most recently
considering them in the context of what he calls a naturalized logic
(modelled on Quine's naturalized epistemology). 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. From
the perspective of third-way reasoning the "rules" implicit in the
fallacies present themselves as heuristic directives to reasoners
rather than as fallacies; hence, it may be that learning from feedback
(having errors corrected) is less trouble than learning the rules to
avoid fallacies in the first place (Woods 2013, p. 215). Woods
illustrates his point by recalling many of the fallacies he originally
identified in his 1992 paper, and subjecting them to this revised
model of analysis thereby overturning the view that these types of
argument are always to be spurned.


### 3.5 The epistemic approach to fallacies



SDF may be seen as closely tied to the logical approach to
fallacies--the fault in arguments it singles out is their
deductive invalidity. But this conception of fallacies turns out to be
inadequate to cover the variety of the core fallacies in two ways: it
is too narrow because it excludes begging the question which is not
invalid, and it is too wide because it condemns good but non-deductive
arguments as fallacies (given that they also satisfy the appearance
condition) because they are invalid. Even if we replace the invalidity
condition in SDF with some less stringent standard of logical weakness
which could overcome the "too wide" problem, it would
still leave the difficulty of accounting for the fallacy of begging
the question unsolved.



Siegel and Biro (1992, 1995) hold an epistemic account of fallacies,
contrasting their view with dialectical/rhetorical approaches, because
matters extraneous to arguments, such as being a practice that leads
to false beliefs or not being persuasive, are not in their view a
sufficient condition to make an argument a fallacy. They take the
position that "it is a conceptual truth about arguments that
their central ... purpose is to provide a bridge from known
truths or justified beliefs to as yet unknown ... truths or as
yet unjustified beliefs" (1992, 92). Only arguments that are
"epistemically serious" can accomplish this; that is, only
arguments that satisfy the extra-formal requirement that premises are
knowable independently of their conclusions, and are more acceptable
epistemically than their conclusions, can fulfill this function. A
purely logical approach to argument will not capture this requirement
because arguments of the same valid form, but with different contents,
may or may not be epistemically serious, depending on whether the
premises are epistemically acceptable relative to the conclusion.



Modifying Biro's (1977, 265-66) examples we can
demonstrate how the requirement of epistemic seriousness plays out
with begging the question. Consider these two arguments:




All men are mortal;
  

Obama is a man;
  

So, Obama is mortal.



All members of the committee are old Etonians;
  

Fortesque is a member of the committee;
  

Fortesque is an old Etonian.




In the first argument the premises are knowable independently of the
conclusion. The major premise can be deduced from other universal
premises about animals, and the minor premise, unlike the conclusion
which must be inferred, can be known by observation. Hence, this
argument does not beg the question. However, in the second argument
(due to Biro, 1977) given the minor premise, the major cannot be known
to be true unless the conclusion is known to be true. Consequently, on
the epistemic approach to fallacies taken by Biro and Siegel, the
second argument, despite the fact that it is valid, is non-serious, it
begs the question, and it is a fallacy. If there was some independent
way of knowing whether the major premise was true, such as that it was
a bylaw that only old Etonians could be committee members, the
argument would be a serious one, and not beg the question.



Biro and Siegel's epistemic account of fallacies is
distinguishable in at least three ways. First, it insists that the
function of arguments is epistemic, and therefore anything that counts
as a fallacy must be an epistemic fault, a breaking of a rule of
epistemic justification. But since logical faults are also epistemic
faults, the epistemic approach to fallacies will include logical
fallacies, although these must also be explicable in terms of
epistemic seriousness. Second, since the epistemological approach does
not insist that all justification must be deductive, it allows the
possibility of their being fallacies (as well as good arguments) by
non-deductive standards, something precluded by SDF. Finally, we
notice that the appearance condition is not considered a factor in
this discussion of fallacies.



Ulrike Hahn and Mike Oaksford (2006a, 2006b) see themselves as
contributing to the epistemic approach to fallacy analysis by
developing a probabilistic analysis of the fallacies. It is part of
their programme for a normative theory of natural language
argumentation. They are motivated by what they perceive as the
shortcomings in other approaches. The logical (deductive) approach
falls short in that it simply divides arguments into valid and invalid
arguments thereby failing to appreciate that natural language
arguments come in various degrees of strength. The alternative
approaches to fallacies, given by procedural (dialectical) and
consensual accounts, they criticize on the basis that they fail to
address the central problem raised by the fallacies: that of the
strength of the reason-claim complex. In Hahn and Oaksford's
view the strength or weakness of the classical fallacies (they are
concerned mostly with the post-Aristotelian ones) is not a result of
their structure or their context of use. It is instead a matter of the
relationship between the evidence and the claim (the contents of the
premises and the conclusion). Evaluation of this relationship is
thought to be best captured by a probabilistic Bayesian account;
accordingly, they adapt Bayes' theorem to arguments evaluation
with the proviso that the probabilities are subjective degrees of
belief, not frequencies. "An argument's strength,"
they write, "is a function of an individual's initial
level of belief in the claim, the availability and observation of
confirmatory (or disconfirmatory) evidence, and the existence and
perceived strength of competing hypotheses" (Corner, et al.
1145). With Korb (2003) they view a fallacy as an argument with a low
probability on the Bayesian model.



Since the variance in input probabilities will result in a range of
outputs in argument strength, this probabilistic approach has the
potential to assign argument strengths anywhere between 0 and 1,
thereby allowing that different tokens of one argument type can vary
greatly in strength, i.e., some will be fallacies and others not.
Also, and this seems to concur with our experience, different arguers
may disagree on the strength of the same arguments since they can
differ in the assignments of the initial probabilities. Hahn and
Oaksford also claim as advantages for their normative theory that it
gives guidance for persuasion since it takes into account the initial
beliefs of audiences. Moreover, their approach contributes to the
study of belief change; that is, to what extent our confidence in the
conclusion changes with the availability of new evidence. 


### 3.6 Dialectical/dialogical approaches to fallacies



Some of the most active new researchers on fallacies take a
dialectical and/or dialogical approach. This can be traced back to
Hamblin (1970, ch. 8) and Lorenzen's (1969) dialogue theory. The
panacea for fallacies that Whately recommended was more logic;
Hamblin, however, proposed a shift from the logical to the dialectical
perspective.



> 
> [W]e need to extend the bounds of Formal Logic; to include features of
> dialectical contexts within which arguments are put forward. To begin
> with, there are criteria of validity of argument that are additional
> to formal ones: for example, those that serve to proscribe
> question-begging. To go on with, there are prevalent but false
> conceptions of the rules of dialogue, which are capable of making
> certain argumentative moves seem satisfactory and unobjectionable
> when, in fact, they conceal and facilitate dialectical malpractice.
> (Hamblin 1970, 254)
> 



The proposal here is to shift the study of fallacies from the contexts
of arguments to the contexts of dialogues (argumentation), formulate
rules for reasonable dialogue activity, and then connect fallacies to
failures of rule-following. Barth and Martens's paper (1977),
which studied the *argumentum ad hominem* by extending
Lorenzen's dialogue tableaux method to include the definitions
of the concepts "line of attack" and "winning
strategy," leads to a conception of fallacies as either failures
to meet one of the necessary conditions of rational dialogical
argumentation, or failures to satisfy sufficient conditions as
specified by production rules of the dialogical method (1977, 96).



The Barth and Martens paper is a bridge between the earlier (quasi-)
formal and subsequent informal dialectical theories, and is explicitly
acknowledged as a major influence by the Pragma-dialectical theory,
the brainchild of Frans van Eemeren and Rob Grootendorst (1984).
Rather than beginning from a logical or epistemological perspective
they start with the role of argumentation in overcoming interpersonal
disagreements. The Pragma-dialecticians propose that inter-personal
argumentation can be analysed as two-party-discussions having four
analytical stages: a confrontation stage in which the participants
become aware of the content of their disagreement; an opening stage in
which the parties agree (most likely implicitly) to shared starting
points and a set of rules to govern the ensuing discussion; an
argumentation stage wherein arguments and doubts about arguments are
expressed and recognized; and a final stage in which a decision about
the initial disagreement is made, if possible, based on what happened
in the argumentation stage.



The Pragma-dialectical theory stipulates a normative ideal of a
*critical discussion* which serves both as a guide to the
reconstruction of natural language argumentation, as well as a
standard for the evaluation of the analysed product of reconstruction.
A set of ten rules has been proposed as constitutive of the
critical-discussion ideal, and the proponents of the theory believe
that rational arguers would accept them. If followed by both parties
to the disagreement, the rules constrain the argumentation decision
procedure such that any resolution reached will be deemed reasonable,
and "every violation of any of the rules of the discussion
procedure for conducting a critical discussion" will be a
fallacy (2004, 175). The rules range over all the four stages of
argumentation: at the confrontation stage there is a rule which says
one may not prevent the other party from expressing their view; for
the argumentation stage there is a rule which requires argumentation
to be logically strong and in accord with one or another of three
general argumentation schemes; at the closing stage there is a rule
that the participants themselves are to decide which party was
successful based on the quality of the argumentation they have made:
if the proponent carries the day, the opponent should acknowledge it,
and *vice versa*.



The Pragma-dialectical theory proposes that each of the core fallacies
can be assigned a place as a violation of one of the rules of a
critical discussion. For example, the *ad baculum* fallacy is a
form of intimidation that violates the rule that one may not attempt
to prevent one's discussion partner from expressing their views;
equivocation is a violation of the rule that formulations in arguments
must be clear and unambiguous; *post hoc ergo propter hoc*
violates the rule that arguments must be instances of schemes
correctly applied. Moreover, on this theory, since any rule violation
is to count as a fallacy this allows for the possibility that there
may be hitherto unrecognized "new fallacies." Among those
proposed are *declaring a standpoint sacrosanct* because that
breaks the rule against the freedom to criticize points of view, and
*evading the burden of proof* which breaks the rule that you
must defend your standpoint if asked to do so (see van Eemeren 2010,
194).



Clearly not all the rules of critical discussions apply directly to
arguments. Some govern other goal-frustrating moves which arguers can
make in the course of settling a difference of opinion, such as
mis-allocating the burden of proof, asking irrelevant questions,
suppressing a point of view, or failing to clarify the meaning of
one's argumentation. In short, the Pragma-dialectical rules of a
critical discussion are not just rules of logic or epistemology, but
rules of conduct for rational discussants, making the theory more like
a moral code than a set of logical principles. Accordingly, this
approach to fallacies rejects all three of the necessary conditions of
SDF: a fallacy need not be an argument, thus the invalidity condition
will not apply either, and the appearance condition is excluded
because of its subjective character (Van Eemeren and Grootendorst
2004, 175).



The Pragma-dialectical analysis of fallacies as rule-breakings in a
procedure for overcoming disagreements has recently been expanded to
take account of the rhetorical dimension of argumentation.
Pragma-dialectics takes the rhetorical dimension to stem from an
arguer's wish to have their view accepted which leads dialoguers
to engage in strategic maneuvering vis-a-vis their dialogue
partners. However, this desire must be put in balance with the
dialectical requirement of being reasonable; that is, staying within
the bounds of the normative demands of critical discussions. The ways
of strategic maneuvering identified are basically three: topic
selection, audience orientation, and the selection of presentational
devices, and these can be effectively deployed at each stage of
argumentation (Van Eemeren 2010, 94). "All derailments of
strategic maneuvering are fallacies," writes van Eemeren (2010,
198), "in the sense that they violate one or more of the rules
for critical discussion and all fallacies can be viewed as derailments
of strategic maneuvering." This means that all fallacies are
ultimately attributable to the rhetorical dimension of argumentation
since, in this model, strategic maneuvering is the entry of rhetoric
into argumentation discussions. "Because each fallacy has, in
principle, sound counterparts that are manifestations of the same mode
of strategic maneuvering" it may not appear to be a fallacy and
it "may pass unnoticed" (Van Eemeren 2010, 199).
Nevertheless, Pragma-dialectics prefers to keep the appearance
condition outside the definition of 'fallacy', treating
the seeming goodness of fallacies as a sometime co-incidental
property, rather than an essential one.



Argumentation evaluation on the Pragma-dialectical approach is done
with an eye to a single ideal model of argumentation. This approach
has been challenged by Douglas Walton who has written more about
fallacies and fallacy theory than anyone else. He has published
individual monographs on many of the well-known fallacies, among them,
*Begging the Question* (1991), *Slippery Slope
Arguments* (1992), *Ad Hominem Arguments* (1998), and a
comprehensive work on fallacy theory, *A Pragmatic Theory of
Fallacy* (1995). Over the years his views have evolved. He has
referred to his theory as "the Pragmatic theory," and like
the Pragma-dialectical theory it has a dialectical/dialogical basis;
however, Walton envisions a number of distinct normative dialectical
frameworks (persuasion dialogue, inquiry dialogue, negotiation
dialogue, etc.) rather than the single model of a critical discussion
proposed by Pragma-dialectics. Postulating different kinds of
dialogues with different starting points and different goals, thinks
Walton, will bring argumentation into closer contact with
argumentation reality. At one point Walton had the idea that fallacies
happened when there was an illicit shift from one kind of a dialogue
to another (1995, 118-23), for example, using arguments
appropriate for a negotiation dialogue in a persuasion dialogue, but
more recently he has turned to other ways of explicating
fallacies.



Although Walton recognizes the class of formal fallacies, his main
interest is in informal fallacies, especially the ones associated with
argumentation schemes. The idea of an argumentation scheme is central
to Walton's theory. Schemes are patterns of commonly used kinds
of defeasible reasoning/argumentation such as appeals to expert
opinion and *ad hominem* arguments. Schemes do not identify
fallacies but rather argument kinds that are sometimes used fairly,
and, other times, fallaciously. With each kind of scheme is associated
a set of critical questions which guide us in deciding whether a given
use of an argument is correct, weak or fallacious. So, if we
consider:



\(E\) is an expert in subject area \(S\);
  

\(E\) asserts \(p\) based on \(E\)'s knowledge of \(S\);
  

So, \(p\).



to be the scheme for the appeal-to-expertise kind of
 argument,[8]
 then there will be a question for each premise: Is \(E\) really an
expert in \(S\)? Did \(E\) say \(p\) when s/he was acting in her/his
professional capacity? (... or did s/he blurt it out while drunk
at an association party?). If the answer to both questions is Yes,
then the argument creates a presumption for the conclusion--but
not a guarantee, for the reasoning is defeasible: other information
may come to light that will override the presumption. If one of the
questions cannot be answered clearly this is an indication that the
argument is weak, and answering No to either of the two questions
cancels the presumption for the conclusion, i.e., makes the argument
into a bad argument from expert opinion. If the bad argument has
"a semblance of correctness about it in [the] context, and poses
a serious obstacle to the realization of the goal of the
dialog," then it is a fallacy (2011,
 380).[9]



The definition of fallacy Walton proposes (1995, 255) has five parts.
A fallacy:


1. an argument (or at least something that purports to be an
argument) that
2. falls short of some standard of correctness;
3. is used in a context of dialogue;
4. has a semblance of correctness about it; and
5. poses a serious problem to the realization of the goal of the
dialogue.



Here we find that Walton has relaxed two of the necessary conditions
of SDF. Purporting to be an argument is enough (it doesn't
really have to be an argument), while falling short of a standard (one
that will vary with the kind of dialogue under consideration) replaces
the invalidity condition. However, the appearance condition, here
expressed as fallacies having a semblance of correctness about them,
remains in full force. The two extra conditions added to fallacy are
that they occur only in contexts of dialogue and that they frustrate
the realization of the goal of the kind of dialogue in which they
occur. In insisting on this dialogical dimension, Walton is in full
sympathy with those who think that fallacies can only be rightly
analysed within a dialectical framework similar to the ones Aristotle
originally studied, and later better defined by Hamblin and Lorenzen.
Walton volunteers a shorter version of the definition of a fallacy as
"a deceptively bad argument that impedes the progress of a
dialogue" (1995, 256).



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 associated more 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 to be 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.



Another recent approach comes from virtue argumentation theory
(modelled on virtue epistemology). Virtue argumentation theory is
characterized by a distinct set of virtues thought to be essential to
good argumentation: willingness to engage in argumentation,
willingness to listen to others and willingness to modify one's
own position (see, e.g., Cohen 2009). These may be supplemented with
epistemic virtues and even in some cases moral virtues. Although
virtues and vices are dispositions of arguers and fallacies are
arguments, it is claimed that good argumentation generally results
from the influence of argumentation virtues and bad argumentation
(including the fallacies) arise because of the vices of arguers. 



Taking the Aristotelian view that virtues are a mean between opposite
kinds of vices, fallacious arguments can be seen as resulting from
arguers moving in one or another direction away from a mean of good
argumentation. Aberdein (2013, 2016) especially has developed this
model for understanding many of the fallacies. We can illustrate the
view by considering appeals to expertise: the associated vices might
be too little respect for reliable authorities at one extreme and too
much deference to authorities at the other extreme. Aberdein develops
the fallacies-as-argumentation-vices analysis in some detail for other
of the ad-arguments and sketches how it might be applied to the other
core fallacies, suggesting it can profitably be extended to all of
them. 



All the fallacies, it is claimed, can be fitted in somewhere in the
classification of argumentational vices, but the converse is not true
although it is possible to bring to light other shortcomings to which
we may fall prey in argumentation. Another aspect of the theory is
that it distributes argumentation vices among both senders and
audiences. Speakers may infect their arguments with vices when they
are, for example, closed minded or lack respect for persons, and
audiences can contribute to fallaciousness by letting their
receptivity be influenced by naivety, an over-reliance on common
sense, or an unfounded bias against a speaker. Perhaps the development
of the virtue argumentation theory approach to fallacies provides a
supplement to Mill's theory of fallacies. He distinguished
(1891, V, i, 3) what he called the moral (dispositional) and
intellectual causes of fallacy. The study of the argumentative vices
envisioned above seems best included under the moral study of
fallacies as the vices can be taken to be the presdisposing causes to
commit intellectual mistakes, i.e., misevaluations of the weight of
evidence. 


## 4. Current issues in fallacy theory


### 4.1 The nature of fallacies



A question that continues to dog fallacy theory is how we are to
conceive of fallacies. There would be advantages to having a unified
theory of fallacies. It would give us a systematic way of demarcating
fallacies and other kinds of mistakes; it would give us a framework
for justifying fallacy judgments, and it would give us a sense of the
place of fallacies in our larger conceptual schemes. Some general
definition of 'fallacy' is wanted but the desire is
frustrated because there is disagreement about the identity of
fallacies. Are they inferential, logical, epistemic or dialectical
mistakes? Some authors insist that they are all of one kind: Biro and
Siegel, for example, that they are epistemic, and Pragma-dialectics
that they are dialectical. There are reasons to think that all
fallacies do not easily fit into one category.



Together the *Sophistical Refutations* and Locke's
*Essay* are the dual sources of our inheritance of fallacies.
However, for four reasons they make for uneasy bedfellows. First, the
*ad* fallacies seem to have a built-in dialectical character,
which, it can be argued, Aristotle's fallacies do not have (they
are not sophistical refutations but are *in* sophistical
refutations). Second, Aristotle's fallacies are logical
mistakes: they have no appropriate employment outside eristic
argumentation whereas the *ad*-fallacies are instances of
*ad*-arguments, often appropriately used in dialogues. Third,
the appearance condition is part of the Aristotelian inheritance but
it is not intimately connected with the *ad*-fallacies
tradition. A fourth reason that contributes to the tension between the
Aristotelian and Lockean traditions in fallacies is that the former
grew out of philosophical problems, largely what are logical and
metaphysical puzzles (consider the many examples in *Sophistical
Refutations*), whereas the *ad*-fallacies are more geared
to social and political topics of popular concern, the subject matter
that most intrigues modern researchers on fallacy theory.



As we look back over our survey we cannot help but observe that
fallacies have been identified in relation to some ideal or model of
good arguments, good argumentation, or rationality. Aristotle's
fallacies are shortcomings of his ideal of deduction and proof,
extended to contexts of refutation. The fallacies listed by Mill are
errors of reasoning in a comprehensive model that includes both
deduction and induction. Those who have defended SDF as the correct
definition of
 'fallacy'[10]
 take logic *simpliciter* or deductive validity as the ideal of
rationality. Informal logicians view fallacies as failures to satisfy
the criteria of what they consider to be a cogent argument. Defenders
of the epistemic approach to fallacies see them as shortfalls of the
standards of knowledge-generating arguments. Finally, those who are
concerned with how we are to overcome our disagreements in a
reasonable way will see fallacies as failures in relation to ideals of
debate or critical discussions.



The standard treatment of the core fallacies has not emerged from a
single conception of good argument or reasonableness but rather, like
much of our unsystematic knowledge, has grown as a hodgepodge
collection of items, proposed at various time and from different
perspectives, that continues to draw our attention, even as the
standards that originally brought a given fallacy to light are
abandoned or absorbed into newer models of rationality. Hence, there
is no single conception of good argument or argumentation to be
discovered behind the core fallacies, and any attempt to force them
all into a single framework, must take efforts to avoid distorting the
character originally attributed to each of them.


### 4.2 The appearance condition



From Aristotle to Mill the appearance condition was an essential part
of the conception of fallacies. However, some of the new,
post-Hamblin, scholars have either ignored it (Finocchiaro, Biro and
Siegel) or rejected it because appearances can vary from person to
person, thus making the same argument a fallacy for the one who is
taken in by the appearance, and not a fallacy for the one who sees
past the appearances. This is unsatisfactory for those who think that
arguments are either fallacies or not. Appearances, it is also argued,
have no place in logical or scientific theories because they belong to
psychology (van Eemeren and Grootendorst, 2004). But Walton (e.g.,
2010) continues to consider appearances an essential part of fallacies
as does Powers (1995, 300) who insists that fallacies must "have
an appearance, however quickly seen through, of being valid." If
the mistake in an argument is not masked by an ambiguity that makes it
appear to be a better argument than it really is, Powers denies it is
a fallacy.



The appearance condition of fallacies serves at least two purposes.
First, it can be part of explanations of why reasonable people make
mistakes in arguments or argumentation: it may be due in part to an
argument's appearing to be better than it really is. Second, it
serves to divide mistakes into two groups: those which are trivial or
the result of carelessness (for which there is no cure other than
paying better attention), and those which we need to learn to detect
through an increased awareness of their seductive nature. Without the
appearance condition, it can be argued, no division can be made
between these two kinds of errors: either there are no fallacies or
all mistakes in argument and/or argumentation are fallacies; a
conclusion that some are willing to accept, but which runs contrary to
tradition. One can also respond that there is an alternative to using
the appearance condition as the demarcation property between fallacies
and casual mistakes, namely, frequency. Fallacies are those mistakes
we must learn to guard against because they occur with noticeable
frequency. To this it may be answered that 'noticeable
frequency' is vague, and is perhaps best explained by the
appearance condition.


### 4.3 Teaching



On the more practical level, there continues to be discussion about
the value of teaching the fallacies to students. Is it an effective
way for them to learn to reason well and to avoid bad arguments? One
reason to think that it is not effective is that the list of fallacies
is not complete, and that even if the group of core fallacies was
extended to incorporate other fallacies we thought worth including, we
could still not be sure that we had a complete prophylactic against
bad arguments. Hence, we are better off teaching the positive criteria
for good arguments/ argumentation which give us a fuller set of
guidelines for good reasoning. But some (Pragma-dialectics and Johnson
and Blair) do think that their stock of fallacies is a complete guard
against errors because they have specified a full set of necessary
conditions for good arguments/argumentation and they hold that
fallacies are just failures to meet one of these conditions.



Another consideration about the value of the fallacies approach to
teaching good reasoning is that it tends to make students overly
critical and lead them to see fallacies where there are not any;
hence, it is maintained we could better advance the instilling of
critical thinking skills by teaching the positive criteria of good
reasoning and arguments (Hitchcock, 1995). In response to this view,
it is argued that, if the fallacies are taught in a non-perfunctory
way which includes the explanations of why they are
fallacies--which normative standards they transgress--then a
course taught around the core fallacies can be effective in instilling
good reasoning skills (Blair 1995).


### 4.4 Biases



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.



Thagard (2011) is more concerned to stress the differences between
fallacies and biases than to find connections between them. He claims
that the model of reasoning articulated by informal logic is not a
good fit with the way that people actually reason and that only a few
of the fallacies are relevant to the kinds of mistakes people actually
make. Thagard's argument depends on his distinction between
argument and inference. Arguments, and fallacies, he takes to be
serial and linguistic, but inferences are brain activities and are
characterized as parallel and multi-modal. By "parallel"
is meant that the brain carries out different processes
simultaneously, and by "multi-modal" that the brain uses
non-linguistic and emotional, as well as linguistic representations in
inferring. Biases (inferential error tendencies) can unconsciously
affect inferring. "Motivated inference," for example,
"involves selective recruitment and assessment of evidence based
on unconscious processes that are driven by emotional considerations
of goals rather than purely cognitive reasoning" (2011, 156).
Thagard volunteers a list of more than fifty of these inferential
error tendencies. Because motivated inferences result from unconscious
mental processes rather than explicit reasoning, the errors in
inferences cannot be exposed simply by identifying a fallacy in a
reconstructed argument. Dealing with biases requires identification of
both conscious and unconscious goals of arguers, goals that can figure
in explanations of why they incline to particular biases.
"Overcoming people's motivated inferences," Thagard
concludes, "is therefore more akin to psychotherapy than
informal logic" (157), and the importance of fallacies is
accordingly marginalized.



In response to these findings, one can admit their relevance to the
pedagogy of critical thinking but still recall the distinction between
what causes mistakes and what the mistakes are. The analysis of
fallacies belongs to the normative study of arguments and
argumentation, and to give an account of what the fallacy in a given
argument is will involve making reference to some norm of
argumentation. It will be an explanation of what the mistake in the
argument is. Biases are relevant to understanding why people commit
fallacies, and how we are to help them get past them, but they do not
help us understand what the fallacy-mistakes are in the first
place--this is not a question of psychology. Continued research
at this intersection of interests will hopefully shed more light on
both biases and fallacies.