## 1. Terminological Clarifications



An argument can be defined as a complex symbolic structure where some
parts, known as the premises, offer support to another part, the
conclusion. Alternatively, an argument can be viewed as a complex
speech act consisting of one or more acts of premising (which assert
propositions in favor of the conclusion), an act of concluding, and a
stated or implicit marker ("hence",
"therefore") that indicates that the conclusion follows
from the premises (Hitchcock
 2007).[1]
 The relation of support between premises and conclusion can be cashed
out in different ways: the premises may guarantee the truth of the
conclusion, or make its truth more probable; the premises may imply
the conclusion; the premises may make the conclusion more acceptable
(or assertible).



For theoretical purposes, arguments may be considered as freestanding
entities, abstracted from their contexts of use in actual human
activities. But depending on one's explanatory goals, there is
also much to be gained from considering arguments as they in fact
occur in human communicative practices. The term generally used for
instances of exchange of arguments is *argumentation*. In what
follows, the convention of using "argument" to refer to
structures of premises and conclusion, and "argumentation"
to refer to human practices and activities where arguments occur as
communicative actions will be adopted.



Argumentation can be defined as the communicative activity of
producing and exchanging reasons in order to support claims or
defend/challenge positions, especially in situations of doubt or
disagreement (Lewinski & Mohammed 2016). It is arguably best
conceived as a kind of *dialogue*, even if one can also
"argue" with oneself, in long speeches or in writing (in
articles or books) for an intended but silent audience, or in groups
rather than in dyads (Lewinski & Aakhus 2014). But
argumentation is a *special* kind of dialogue: indeed, most of
the dialogues we engage in are not instances of argumentation, for
example when asking someone if they know what time it is, or when
someone shares details about their vacation. Argumentation only occurs
when, upon making a claim, someone receives a request for further
support for the claim in the form of reasons, or estimates herself
that further justification is required (Jackson & Jacobs 1980;
Jackson, 2019). In such cases, dialogues of "giving and asking
for reasons" ensue (Brandom, 1994; Bermejo Luque 2011). Since
most of what we know we learn from others, argumentation seems to be
an important mechanism to filter the information we receive, instead
of accepting what others tell us uncritically (Sperber,
Clement, et al. 2010).



The study of arguments and argumentation is also closely connected to
the study of *reasoning*, understood as the process of reaching
conclusions on the basis of careful, reflective consideration of the
available information, i.e., by an examination of *reasons*.
According to a widespread view, reasoning and argumentation are
related (as both concern reasons) but fundamentally different
phenomena: reasoning would belong to the mental realm of
thinking--an individual inferring new information from the
available information by means of careful consideration of
reasons--whereas argumentation would belong to the public realm
of the *exchange* of reasons, expressed in language or other
symbolic media and intended for an audience. However, a number of
authors have argued for a different view, namely that reasoning and
argumentation are in fact two sides of the same coin, and that what is
known as reasoning is by and large the internalization of practices of
argumentation (MacKenzie 1989; Mercier & Sperber 2017; Mercier
2018). For the purposes of this entry, we can assume a close
connection between reasoning and argumentation so that relevant
research on reasoning can be suitably included in the discussions to
come.


## 2. Types of Arguments



Arguments come in many kinds. In some of them, the truth of the
premises is supposed to guarantee the truth of the conclusion, and
these are known as *deductive* arguments. In others, the truth
of the premises should make the truth of the conclusion more likely
while not ensuring complete certainty; two well-known classes of such
arguments are *inductive* and *abductive* arguments (a
distinction introduced by Peirce, see entry on
 C.S. Peirce).
 Unlike deduction, induction and abduction are thought to be
ampliative: the conclusion goes beyond what is (logically) contained
in the premises. Moreover, a type of argument that features
prominently across different philosophical traditions, and yet does
not fit neatly into any of the categories so far discussed, are
*analogical* arguments. In this section, these four kinds of
arguments are presented. The section closes with a discussion of
fallacious arguments, that is, arguments that seem legitimate and
"good", but in fact are
 not.[2]


### 2.1 Deduction



Valid deductive arguments are those where the truth of the premises
necessitates the truth of the conclusion: the conclusion cannot
*but* be true if the premises are true. Arguments having this
property are said to be deductively *valid*. A valid argument
whose premises are also true is said to be *sound*. Examples of
valid deductive arguments are the familiar syllogisms, such as:



> 
> 
> 
> All humans are living beings.
> 
> All living beings are mortal.
> 
> Therefore, all humans are mortal.
> 
> 
> 
> 



In a deductively valid argument, the conclusion will be true in
*all* situations where the premises are true, with no
exceptions. A slightly more technical gloss of this idea goes as
follows: in all possible worlds where the premises hold, the
conclusion will also hold. This means that, if I know the premises of
a deductively valid argument to be true of a given situation, then I
can conclude with absolute certainty that the conclusion is also true
of that situation. An important property typically associated with
deductive arguments (but with exceptions, such as in relevant logic),
and which differentiates them from inductive and abductive arguments,
is the property of *monotonicity*: if premises *A* and
*B* deductively imply conclusion *C*, then the addition of
any arbitrary premise *D* will not invalidate the argument. In
other words, if the argument "*A* and *B*; therefore
*C*" is deductively valid, then the argument
"*A*, *B* and *D*; therefore *C*" is
equally deductively valid.



Deductive arguments are the objects of study of familiar logical
systems such as (classical) propositional and predicate logic, as well
as of subclassical systems such as intuitionistic and relevant logics
(although in relevant logic the property of monotonicity does not
hold, as it may lead to violations of criteria of relevance between
premises and conclusion--see entry on
 relevance logic).
 In each of these systems, the relation of logical consequence in
question satisfies the property of necessary truth-preservation (see
entry on
 logical consequence).
 This is not surprising, as these systems were originally designed to
capture arguments of a very specific kind, namely
*mathematical* arguments (proofs), in the pioneering work of
Frege, Russell, Hilbert, Gentzen, and others. Following a paradigm
established in ancient Greek mathematics and famously captured in
Euclid's *Elements*, argumentative steps in mathematical
proofs (in this tradition at least) must have the property of
necessary truth preservation (Netz 1999). This paradigm remained
influential for millennia, and still codifies what can be described as
the "classical" conception of mathematical proof (Dutilh
Novaes 2020a), even if practices of proof are ultimately also quite
diverse. (In fact, there is much more to argumentation in mathematics
than just deductive argumentation [Aberdein & Dove 2013].)



However, a number of philosophers have argued that deductive validity
and necessary truth preservation in fact come apart. Some have reached
this conclusion motivated by the familiar logical paradoxes such as
the Liar or Curry's paradox (Beall 2009; Field 2008; see entries
on the
 Liar paradox
 and on
 Curry's paradox).
 Others have defended the idea that there are such things as
*contingent logical truths* (Kaplan 1989; Nelson & Zalta
2012), which thus challenge the idea of necessary truth preservation.
It has also been suggested that what is preserved in the transition
from premises to conclusions in deductive arguments is in fact
*warrant or assertibility* rather than truth (Restall 2004).
Yet others, such as proponents of preservationist approaches to
paraconsistent logic, posit that what is preserved by the deductive
consequence relation is the coherence, or incoherence, of a set of
premises (Schotch, Brown, & Jennings 2009; see entry on
 paraconsistent logic).
 Nevertheless, it is fair to say that the view that deductive validity
is to be understood primarily in terms of necessary truth preservation
is still the received view.



Relatedly, there are a number of pressing philosophical issues
pertaining to the justification of deduction, such as the exact nature
of the necessity involved in deduction (metaphysical, logical,
linguistic, epistemic; Shapiro 2005), and the possibility of offering
a non-circular foundation for deduction (Dummett 1978). Furthermore,
it is often remarked that the fact that a deductive argument is not
ampliative may entail that it cannot be informative, which in turn
would mean that its usefulness is quite limited; this problem has been
described as "the scandal of deduction" (Sequoiah-Grayson
2008).



Be that as it may, deductive arguments have occupied a special place
in philosophy and the sciences, ever since Aristotle presented the
first fully-fledged theory of deductive argumentation and reasoning in
the *Prior Analytics* (and the corresponding theory of
scientific demonstration in the *Posterior Analytics*; see
 Historical Supplement).
 The fascination for deductive arguments is understandable, given
their allure of certainty and indubitability. The *more
geometrico* (a phrase introduced by Spinoza to describe the
argumentative structure of his *Ethics* as following "a
geometrical style"--see entry on
 Spinoza)
 has been influential in many fields other than mathematics. However,
the focus on deductive arguments at the expense of other types of
arguments has arguably skewed investigations on argument and
argumentation too much in one specific direction (see (Bermejo-Luque
2020) for a critique of deductivism in the study of
argumentation).



In recent decades, the view that everyday reasoning and argumentation
by and large do not follow the canons of deductive argumentation has
been gaining traction. In psychology of reasoning, Oaksford and Chater
were the first to argue already in the 1980s that human reasoning
"in the wild" is essentially probabilistic, following the
basic canons of Bayesian probabilities (Oaksford & Chater 2018;
Elqayam 2018; see
 section 5.3
 below). Computer scientists and artificial intelligence researchers
have also developed a strong interest in non-monotonic reasoning and
argumentation (Reiter 1980), recognizing that, outside specific
scientific contexts, human reasoning tends to be deeply
*defeasible* (Pollock 1987; see entries on
 non-monotonic logic
 and
 defeasible reasoning).
 Thus seen, deductive argumentation might be considered as the
exception rather than the rule in human argumentative practices taken
as a whole (Dutilh Novaes 2020a). But there are others, especially
philosophers, who still maintain that the use of deductive reasoning
and argumentation is widespread and extends beyond niches of
specialists (Shapiro 2014; Williamson 2018).


### 2.2 Induction



Inductive arguments are arguments where observations about past
instances and regularities lead to conclusions about future instances
and general principles. For example, the observation that the sun has
risen in the east every single day until now leads to the conclusion
that it will rise in the east tomorrow, and to the general principle
"the sun always rises in the east". Generally speaking,
inductive arguments are based on statistical frequencies, which then
lead to generalizations beyond the sample of cases initially under
consideration: from the observed to the unobserved. In a good, i.e.,
*cogent*, inductive argument, the truth of the premises
provides some degree of support for the truth of the conclusion. In
contrast with a deductively valid argument, in an inductive argument
the degree of support will never be maximal, as there is always the
possibility of the conclusion being false given the truth of the
premises. A gloss in terms of possible worlds might be that, while in
a deductively valid argument the conclusion will hold in all possible
worlds where the premises hold, in a good inductive argument the
conclusion will hold in a significant proportion of the possible
worlds where the premises hold. The proportion of such worlds may give
a measure of the strength of support of the premises for the
conclusion (see entry on
 inductive logic).



Inductive arguments have been recognized and used in science and
elsewhere for millennia. The concept of induction (*epagoge* in
Greek) was understood by Aristotle as a progression from particulars
to a universal, and figured prominently both in his conception of the
scientific method and in dialectical practices (see entry on
 Aristotle's logic, section 3.1).
 However, a deductivist conception of the scientific method remained
overall more influential in Aristotelian traditions, inspired by the
theory of scientific demonstration of the *Posterior
Analytics*. It is only with the so-called "scientific
revolution" of the early modern period that experiments and
observation of individual cases became one of the pillars of
scientific methodology, a transition that is strongly associated with
the figure of Francis Bacon (1561-1626; see entry on
 Francis Bacon).



Inductive inferences/arguments are ubiquitous both in science and in
everyday life, and for the most part quite reliable. The functioning
of the world around us seems to display a fair amount of statistical
regularity, and this is referred to as the "Uniformity
Principle" in the literature on the problem of induction (to be
discussed shortly). Moreover, it has been argued that generalizing
from previously observed frequencies is the most basic principle of
human cognition (Clark 2016).



However, it has long been recognized that inductive
inferences/arguments are not unproblematic. Hume famously offered the
first influential formulation of what became known as "the
problem of induction" in his *Treatise of Human Nature*
(see entries on
 David Hume
 and on
 the problem of induction;
 Howson 2000). Hume raises the question of what grounds the
correctness of inductive inferences/arguments, and posits that there
must be an argument establishing the validity of the Uniformity
Principle for inductive inferences to be truly justified. He goes on
to argue that this argument cannot be deductive, as it is not
inconceivable that the course of nature may change. But it cannot be
probable either, as probable arguments already presuppose the validity
of the Uniformity Principle; circularity would ensue. Since these are
the only two options, he concludes that the Uniformity Principle
cannot be established by rational argument, and hence that induction
cannot be justified.



A more recent influential critique of inductive arguments is the one
offered in (Harman 1965). Harman argues that either enumerative
induction is not always warranted, or it is always warranted but
constitutes an uninteresting special case of the more general category
of inference to the best explanation (see next section). The upshot is
that, for Harman, induction should not be considered a warranted form
of inference in its own right.



Given the centrality of induction for scientific practice, there have
been numerous attempts to respond to the critics of induction, with
various degrees of success. Among those, an influential recent
response to the problem of induction is Norton's material theory
of induction (Norton 2003). But the problem has not prevented
scientists and laypeople alike from continuing to use induction
widely. More recently, the use of statistical frequencies for social
categories to draw conclusions about specific individuals has become a
matter of contention, both at the individual level (see entry on
 implicit bias)
 and at the institutional level (e.g., the use of predictive
algorithms for law enforcement [Jorgensen Bolinger 2021]). These
debates can be seen as reoccurrences of Hume's problem of
induction, now in the domain of social rather than of natural
phenomena.


### 2.3 Abduction



An abductive argument is one where, from the observation of a few
relevant facts, a conclusion is drawn as to what could possibly
*explain* the occurrence of these facts (see entry on
 abduction).
 Abduction is widely thought to be ubiquitous both in science and in
everyday life, as well as in other specific domains such as the law,
medical diagnosis, and explainable artificial intelligence (Josephson
& Josephson 1994). Indeed, a good example of abduction is the
closing argument by a prosecutor in a court of law who, after
summarizing the available evidence, concludes that the most plausible
explanation for it is that the defendant must have committed the crime
they are accused of.



Like induction, and unlike deduction, abduction is not necessarily
truth-preserving: in the example above, it is still possible that the
defendant is not guilty after all, and that some other, unexpected
phenomena caused the evidence to emerge. But abduction is
significantly different from induction in that it does not only
concern the generalization of prior observation for prediction (though
it may also involve statistical data): rather, abduction is often
backward-looking in that it seeks to explain something that has
already happened. The key notion is that of bringing together
apparently independent phenomena or events as explanatorily and/or
causally connected to each other, something that is absent from a
purely inductive argument that only appeals to observed frequencies.
Cognitively, abduction taps into the well-known human tendency to seek
(causal) explanations for phenomena (Keil 2006).



As noted, deduction and induction have been recognized as important
classes of arguments for millennia; the concept of abduction is by
comparison a latecomer. It is important to notice though that
explanatory arguments as such are not latecomers; indeed,
Aristotle's very conception of scientific demonstration is based
on the concept of explaining causes (see entry on
 Aristotle).
 What is recent is the conceptualization of abduction as a special
class of arguments, and the term itself. The term was introduced by
Peirce as a third class of inferences distinct from deduction and
induction: for Peirce, abduction is understood as the process of
forming explanatory hypotheses, thus leading to new ideas and concepts
(whereas for him deduction and induction could not lead to new ideas
or theories; see the entry on
 Peirce). Thus seen,
abduction pertains to contexts of *discovery*, in which case it
is not clear that it corresponds to instances of arguments, properly
speaking. In its modern meaning, however, abduction pertains to
contexts of *justification*, and thus to speak of abductive
arguments becomes appropriate. An abductive argument is now typically
understood as an *inference to the best explanation* (Lipton
1971 [2003]), although some authors contend that there are good
reasons to distinguish the two concepts (Campos 2011).



While the main ideas behind abduction may seem simple enough, cashing
out more precisely how exactly abduction works is a complex matter
(see entry on
 abduction).
 Moreover, it is not clear that abductive arguments are always or even
generally reliable and cogent. Humans seem to have a tendency to
overshoot in their quest for causal explanations, and often look for
simplicity where there is none to be found (Lombrozo 2007; but see
Sober 2015 on the significance of parsimony in scientific reasoning).
There are also a number of philosophical worries pertaining to the
justification of abduction, especially in scientific contexts; one
influential critique of abduction/inference to the best explanation is
the one articulated by van Fraassen (Fraassen 1989). A frequent
concern pertains to the connection between explanatory superiority and
truth: are we entitled to conclude that the conclusion of an abductive
argument is true solely on the basis of it being a good (or even the
best) explanation for the phenomena in question? It seems that no
amount of philosophical a priori theorizing will provide justification
for the leap from explanatory superiority to truth. Instead, defenders
of abduction tend to offer empirical arguments showing that abduction
tends to be a reliable rule of inference. In this sense, abduction and
induction are comparable: they are widely used, grounded in very basic
human cognitive tendencies, but they give rise to a number of
difficult philosophical problems.


### 2.4 Analogy



Arguments by analogy are based on the idea that, if two things are
similar, what is true of one of them is likely to be true of the other
as well (see entry on
 analogy and analogical reasoning).
 Analogical arguments are widely used across different domains of
human activity, for example in legal contexts (see entry on
 precedent and analogy in legal reasoning).
 As an example, take an argument for the wrongness of farming
non-human animals for food consumption: if an alien species farmed
humans for food, that would be wrong; so, by analogy, it is wrong for
us humans to farm non-human animals for food. The general idea is
captured in the following schema (adapted from the entry on
 analogy and analogical reasoning;
 *S* is the source domain and *T* the target domain of the
analogy):


1. *S* is similar to *T* in certain (known) respects.
2. *S* has some further feature *Q*.
3. Therefore, *T* also has the feature *Q*, or some
feature *Q*\* similar to *Q*.



The first premise establishes the analogy between two situations,
objects, phenomena etc. The second premise states that the source
domain has a given property. The conclusion is then that the target
domain also has this property, or a suitable counterpart thereof.
While informative, this schema does not differentiate between good and
bad analogical arguments, and so does not offer much by way of
explaining what grounds (good) analogical arguments. Indeed,
contentious cases usually pertain to premise 1, and in particular to
whether *S* and *T* are sufficiently similar in a way that
is relevant for having or not having feature *Q*.



Analogical arguments are widely present in all known philosophical
traditions, including three major ancient traditions: Greek, Chinese,
and Indian (see
 Historical Supplement).
 Analogies abound in ancient Greek philosophical texts, for example in
Plato's dialogues. In the *Gorgias*, for instance, the
knack of rhetoric is compared to pastry-baking--seductive but
ultimately unhealthy--whereas philosophy would correspond to
medicine--potentially painful and unpleasant but good for the
soul/body (Irani 2017). Aristotle discussed analogy extensively in the
*Prior Analytics* and in the *Topics* (see
 section 3.2 of the entry on analogy and analogical reasoning).
 In ancient Chinese philosophy, analogy occupies a very prominent
position; indeed, it is perhaps the main form of argumentation for
Chinese thinkers. Mohist thinkers were particularly interested in
analogical arguments (see entries on
 logic and language in early Chinese philosophy,
 Mohism and the
 Mohist canons).
 In the Latin medieval tradition too analogy received sustained
attention, in particular in the domains of logic, theology and
metaphysics (see entry on
 medieval theories of analogy).



Analogical arguments continue to occupy a central position in
philosophical discussions, and a number of the most prominent
philosophical arguments of the last decades are analogical arguments,
e.g., Jarvis Thomson's violinist argument purportedly showing
the permissibility of abortion (Thomson 1971), and Searle's
Chinese Room argument purportedly showing that computers cannot
display real understanding (see entry on the
 Chinese Room argument).
 (Notice that these two arguments are often described as thought
experiments [see entry on
 thought experiments],
 but thought experiments are often based on analogical principles when
seeking to make a point that transcends the thought experiment as
such.) The Achilles' heel of analogical arguments can be
illustrated by these two examples: both arguments have been criticized
on the grounds that the purported similarity between the source and
the target domains is not sufficient to extrapolate the property of
the source domain (the permissibility of disconnecting from the
violinist; the absence of understanding in the Chinese room) to the
target domain (abortion; digital computers and artificial
intelligence).



In sum, while analogical arguments in general perhaps confer a lesser
degree of conviction than the other three kinds of arguments
discussed, they are widely used both in professional circles and in
everyday life. They have rightly attracted a fair amount of attention
from scholars in different disciplines, and remain an important object
of study (see entry on
 analogy and analogical reasoning).


### 2.5 Fallacies



One of the most extensively studied types of arguments throughout the
centuries are, perhaps surprisingly, arguments that appear legitimate
but are not, known as *fallacious arguments*.
From early on, the investigation of such arguments occupied a
prominent position in Aristotelian logical traditions, inspired in
particular by his book *Sophistical Refutations*
(see
 Historical Supplement).
 The thought is that, to argue well, it is not sufficient to be able
to produce and recognize good arguments; it is equally (or perhaps
even more) important to be able to recognize bad arguments by others,
and to avoid producing bad arguments oneself. This is particularly
true of the tricky cases, namely arguments that appear legitimate but
are not, i.e., fallacies.



Some well-know types of fallacies include (see entry on
 fallacies
 for a more extensive discussion):


* The fallacy of equivocation, which occurs when an arguer exploits
the ambiguity of a term or phrase which has occurred at least twice in
an argument to draw an unwarranted conclusion.
* The fallacy of begging the question, when one of the premises and
the conclusion of an argument are the same proposition, but
differently formulated.
* The fallacy of appeal to authority, when a claim is supported by
reference to an authority instead of offering reasons to support
it.
* The ad hominem fallacy, which involves bringing negative aspects
of an arguer, or their situation, to argue against the view they are
advancing.
* The fallacy of faulty analogy, when an analogy is used as an
argument but there is not sufficient relevant similarity between the
source domain and the target domain (as discussed above).



Beyond their (presumed?) usefulness in teaching argumentative skills,
the literature on fallacies raises a number of important philosophical
discussions, such as: What determines when an argument is fallacious or rather a
legitimate argument? (See
 section 4.3
 below on Bayesian accounts of fallacies) What causes certain arguments to be fallacious? Is the focus on fallacies a useful approach to arguments at all?
(Massey 1981) Despite the occasional criticism, the concept of fallacies remains
central in the study of arguments and argumentation.


## 3. Types of Argumentation



Just as there are different types of arguments, there are different
types of argumentative situations, depending on the communicative
goals of the persons involved and background conditions. Argumentation
may occur when people are trying to reach consensus in a situation of
dissent, but it may also occur when scientists discuss their findings
with each other (to name but two examples). Specific rules of
argumentative engagement may vary depending on these different types
of argumentation.



A related point extensively discussed in the recent literature
pertains to the function(s) of
 argumentation.[3]
 What's the point of arguing? While it is often recognized that
argumentation may have multiple functions, different authors tend to
emphasize specific functions for argumentation at the expense of
others. This section offers an overview of discussions on types of
argumentation and its functions, demonstrating that argumentation is a
multifaceted phenomenon that has different applications in different
circumstances.


### 3.1 Adversarial and cooperative argumentation



A question that has received much attention in the literature of the
past decades pertains to whether the activity of argumentation is
primarily adversarial or primarily cooperative. This question in fact
corresponds to two sub-questions: the *descriptive* question of
whether instances of argumentation are on the whole primarily
adversarial or cooperative; and the *normative* question of
whether argumentation *should* be (primarily) adversarial or
cooperative. A number of authors have answered "adversarial" to the
descriptive question and "cooperative" to the normative
question, thus identifying a discrepancy between practices and
normative ideals that must be remedied (or so they claim; Cohen 1995).




A case in point: recently, a number of far-right Internet personalities
have advocated the idea that argumentation can be used to overpower
one's opponents, as described in the book *The Art of the
Argument: Western Civilization's Last Stand* (2017) by the
white supremacist S. Molyneux. Such aggressive practices reflect a
vision of argumentation as a kind of competition or battle, where the
goal is to "score points" and "beat the
opponent". Authors who have criticized (overly) adversarial
practices of argumentation include (Moulton 1983; Gilbert 1994; Rooney
2012; Hundleby 2013; Bailin & Battersby 2016). Many (but not all)
of these authors formulated their criticism specifically from a
feminist perspective (see entry on
 feminist perspectives on argumentation).



Feminist critiques of adversarial argumentation challenge ideals of
argumentation as a form of competition, where masculine-coded values
of aggression and violence prevail (Kidd 2020). For these authors,
such ideals encourage argumentative performances where excessive use
of forcefulness is on display. Instances of aggressive argumentation
in turn have a number of problematic consequences: epistemic
consequences--the pursuit of truth is not best served by
adversarial argumentation--as well as moral/ethical/political
consequences--these practices exclude a number of people from
participating in argumentative encounters, namely those for whom
displays of aggression do not constitute socially acceptable behavior
(women and other socially disadvantaged groups in particular). These
authors defend alternative conceptions of argumentation as a
cooperative, nurturing activity (Gilbert 1994; Bailin & Battersby
2016), which are traditionally feminine-coded values. Crucially, they
view adversarial conceptions of argumentation as *optional*,
maintaining that the alternatives are equally legitimate and that
cooperative conceptions should be adopted and cultivated.



By contrast, others have argued that adversariality, when suitably
understood, can be seen as an integral and in fact desirable component
of argumentation (Govier 1999; Aikin 2011; Casey 2020; but notice that
these authors each develop different accounts of adversariality in
argumentation). Such authors answer "adversarial" both to
the descriptive and to the normative questions stated above. One
overall theme is the need to draw a distinction between (excessive)
aggressiveness and adversariality as such. Govier, for example,
distinguishes between ancillary (negative) adversariality and minimal
adversariality (Govier 1999). The thought is that, while the feminist
critique of excessive aggression in argumentation is well taken,
adversariality conceived and practiced in different ways need not have
the detrimental consequences of more extreme versions of belligerent
argumentation. Moreover, for these authors, adversariality in
argumentation is simply not optional: it is an intrinsic feature of
argumentative practices, but these practices also require a background
of cooperation and agreement regarding, e.g., the accepted rules of
inference.



But ultimately, the presumed opposition between adversarial and
cooperative conceptions of argumentation may well be merely apparent.
It may be argued for example that actual argumentative encounters
ought to be adversarial or cooperative to different degrees, as
different types of argumentation are required for different situations
(Dutilh Novaes forthcoming). Indeed, perhaps we should not look for a
one-fits-all model of how argumentation ought to be conducted across
different contexts and situation, given the diversity of uses of
argumentation.


### 3.2 Argumentation as an epistemic practice



We speak of argumentation as an epistemic practice when we take its
primary purpose to be that of improving our beliefs and increasing
knowledge, or of fostering understanding. To engage in argumentation
can be a way to acquire more accurate beliefs: by examining critically
reasons for and against a given position, we would be able to weed out
weaker, poorly justified beliefs (likely to be false) and end up with
stronger, suitably justified beliefs (likely to be true). From this
perspective, the goal of engaging in argumentation is to
*learn*, i.e., to improve one's epistemic position (as
opposed to argumentation "to win" (Fisher & Keil
2016)). Indeed, argumentation is often said to be
*truth-conducive* (Betz 2013).



The idea that argumentation can be an epistemically beneficial process
is as old as philosophy itself. In every major historical
philosophical tradition, argumentation is viewed as an essential
component of philosophical reflection precisely because it may be used
to aim at the truth (indeed this is the core of Plato's critique
of the Sophists and their excessive focus on persuasion at the expense
of truth (Irani 2017; see
 Historical Supplement).
 Recent proponents of an epistemological approach to argumentation
include (Goldman 2004; Lumer 2005; Biro & Siegel 2006). Alvin
Goldman captures this general idea in the following terms:



> 
> 
> Norms of good argumentation are substantially dedicated to the
> promotion of truthful speech and the exposure of falsehood, whether
> intentional or unintentional. [...] Norms of good argumentation
> are part of a practice to encourage the exchange of truths through
> sincere, non-negligent, and mutually corrective speech. (Goldman 1994:
> 30)
> 
> 
> 



Of course, it is at least in theory possible to engage in
argumentation with oneself along these lines, solitarily weighing the
pros and cons of a position. But a number of philosophers, most
notably John Stuart Mill, maintain that *interpersonal*
argumentative situations, involving people who truly disagree with
each other, work best to realize the epistemic potential of
argumentation to improve our beliefs (a point he developed in *On
Liberty* (1859; see entry on
 John Stuart Mill).
 When our ideas are challenged by engagement with those who disagree
with us, we are forced to consider our own beliefs more thoroughly and
critically. The result is that the remaining beliefs, those that have
survived critical challenge, will be better grounded than those we
held before such encounters. Dissenters thus force us to stay
epistemically alert instead of becoming too comfortable with existing,
entrenched beliefs. On this conception, arguers cooperate with each
other precisely by being adversarial, i.e., by adopting a critical
stance towards the positions one disagrees with.



The view that argumentation aims at epistemic improvement is in many
senses appealing, but it is doubtful that it reflects the actual
outcomes of argumentation in many real-life situations. Indeed, it
seems that, more often than not, we are not Millians when arguing: we
do not tend to engage with dissenting opinions with an open mind.
Indeed, there is quite some evidence suggesting that arguments are in
fact not a very efficient means to change minds in most real-life
situations (Gordon-Smith 2019). People typically do not like to change
their minds about firmly entrenched beliefs, and so when confronted
with arguments or evidence that contradict these beliefs, they tend to
either look away or to discredit the source of the argument as
unreliable (Dutilh Novaes 2020c)--a phenomenon also known as
"confirmation bias" (Nickerson 1998).



In particular, arguments that threaten our core beliefs and our sense
of belonging to a group (e.g., political beliefs) typically trigger
all kinds of motivated reasoning (Taber & Lodge 2006; Kahan 2017)
whereby one outright rejects those arguments without properly engaging
with their content. Relatedly, when choosing among a vast supply of
options, people tend to gravitate towards content and sources that
confirm their existing opinions, thus giving rise to so-called
"echo chambers" and "epistemic bubbles"
(Nguyen 2020). Furthermore, some arguments can be deceptively
convincing in that they look valid but are not (Tindale 2007; see
entry on
 fallacies).
 Because most of us are arguably not very good at spotting fallacious
arguments, especially if they are arguments that lend support to the
beliefs we already hold, engaging in argumentation may in fact
*decrease* the accuracy of our beliefs by persuading us of
false conclusions with incorrect arguments (Fantl 2018).



In sum, despite the optimism of Mill and many others, it seems that
engaging in argumentation will not automatically improve our beliefs
(even if this may occur in some
 circumstances).[4]
 However, it may still be argued that an epistemological approach to
argumentation can serve the purpose of providing a *normative
ideal* for argumentative practices, even if it is not always a
descriptively accurate account of these practices in the messy real
world. Moreover, at least *some* concrete instances of
argumentation, in particular argumentation in science (see
 section 4.5
 below) seem to offer successful examples of epistemic-oriented
argumentative practices.


### 3.3 Consensus-oriented argumentation



Another important strand in the literature on argumentation are
theories that view *consensus* as the primary goal of
argumentative processes: to eliminate or resolve a difference of
(expressed) opinion. The tradition of pragma-dialectics is a prominent
recent exponent of this strand (Eemeren & Grootendorst 2004).
These consensus-oriented approaches are motivated by the social
complexity of human life, and the attribution of a role of social
coordination to argumentation. Because humans are social animals who
must often cooperate with other humans to successfully accomplish
certain tasks, they must have mechanisms to align their beliefs and
intentions, and subsequently their actions (Tomasello 2014). The
thought is that argumentation would be a particularly suitable
mechanism for such alignment, as an exchange of reasons would make it
more likely that differences of opinion would decrease (Norman 2016).
This may happen precisely because argumentation would be a good way to
track truths and avoid falsehoods, as discussed in the previous
section; by being involved in the same epistemic process of exchanging
reasons, the participants in an argumentative situation would all come
to converge towards the truth, and thus the upshot would be that they
also come to agree with each other. However, consensus-oriented views
need not presuppose that argumentation is truth-conducive: the
ultimate goal of such instances of argumentation is that of social
coordination, and for this tracking truth is not a requirement
(Patterson 2011).



In particular, the very notion of *deliberative democracy* is
viewed as resting crucially on argumentative practices that aim for
consensus (Fishkin 2016; see entry on
 democracy).
 (For present purposes, "deliberation" and
"argumentation" can be treated as roughly synonymous). In
a deliberative democracy, for a decision to be legitimate, it must be
preceded by authentic public deliberation--a discussion of the
pros and cons of the different options--not merely the
aggregation of preferences that occurs in voting. Moreover, in
democratic deliberation, when full consensus does not emerge, the
parties involved may opt for a compromise solution, e.g., a
coalition-based political system.



A prominent theorist of deliberative democracy thus understood is
Jurgen Habermas, whose "discourse theory of law and
democracy" relies heavily on practices of political
justification and argumentation taking place in what he calls
"the public sphere" (Habermas 1992 [1996]; 1981 [1984];
see entry on
 Habermas).
 He starts from the idea that politics allows for the collective
organization of people's lives, including the common rules they
will live by. Political argumentation is a form of communicative
practice, so general assumptions for communicative practices in
general apply. However, additional assumptions apply as well (Olson
2011 [2014]). In particular, deliberating participants must accept
that anyone can participate in these discursive practices (democratic
deliberation should be inclusive), and that anyone can introduce and
challenge claims that are made in the public sphere (democratic
deliberation should be free). They must also see one another as having
equal status, at least for the purposes of deliberation (democratic
deliberation should be equal). In turn, critics of Habermas's
account view it as unrealistic, as it presupposes an ideal situation
where all citizens are treated equally and engage in public debates in
good faith (Mouffe 1999; Geuss 2019).



More generally, it seems that it is only under quite specific
conditions that argumentation reliably leads to consensus (as also
suggested by formal modeling of argumentative situations (Betz 2013;
Olsson 2013; Mas & Flache 2013)). Consensus-oriented
argumentation seems to work well in cooperative contexts, but not so much in situations of conflict (Dutilh Novaes forthcoming). In
particular, the discussing parties must already have a significant
amount of background agreement--especially agreement on what
counts as a legitimate argument or compelling evidence--for
argumentation and deliberation to lead to consensus. Especially in
situations of deep disagreement (Fogelin 1985), it seems that the
potential of argumentation to lead to consensus is quite limited.
Instead, in many real-life situations, argumentation often leads to
the opposite result; people disagree with each other even more after
engaging in argumentation (Sunstein 2002). This is the well-documented
phenomenon of *group polarization*, which occurs when an
initial position or tendency of individual members of a group becomes
more extreme after group discussion (Isenberg 1986).



In fact, it may be argued that argumentation will often create or
exacerbate conflict and adversariality, rather than leading to the
resolution of differences of opinions. Furthermore, a focus on
consensus may end up reinforcing and perpetuating existing unequal
power relations in a society. 



> 
> 
> In an unjust society, what purports to be a cooperative exchange of
> reasons really perpetuates patterns of oppression. (Goodwin 2007: 77)
> 
> 
> 
> 



This general point has been made by a number of political thinkers
(e.g., Young 2000), who have highlighted the exclusionary implications
of consensus-oriented political deliberation. The upshot is that
consensus may not only be an unrealistic goal for argumentation; it
may not even be a *desirable* goal for argumentation in a
number of situations (e.g., when there is great power imbalance).
Despite these concerns, the view that the primary goal of
argumentation is to aim for consensus remains influential in the
literature.


### 3.4 Argumentation and conflict management



Finally, a number of authors have attributed to argumentation the
potential to manage (pre-existing) conflict. In a sense, the
consensus-oriented view of argumentation just discussed is a special
case of conflict management argumentation, based on the assumption
that the best way to manage conflict and disagreement is to aim for
consensus and thus *eliminate* conflict. But conflict can be
managed in different ways, not all of them leading to consensus;
indeed, some authors maintain that argumentation may help mitigate
conflict even when the explicit aim is not that of reaching consensus.
Importantly, authors who identify conflict management (or variations
thereof) as a function for argumentation differ in their overall
appreciation of the value of argumentation: some take it to be at best
futile and at worst
 destructive,[5]
 while others attribute a more positive role to argumentation in
conflict management.



To this category also belong the conceptualizations of
argumentation-as-war discussed (and criticized) by a number of authors
(Cohen 1995; Bailin & Battersby 2016); in such cases, conflict is
not so much managed but rather *enacted* (and possibly
exacerbated) by means of argumentation. Thus seen, the function of
argumentation would not be fundamentally different from the function
of organized competitive activities such as sports or even war (with
suitable rules of engagement; Aikin 2011).



When conflict emerges, people have various options: they may choose
not to engage and instead prefer to flee; they may go into full-blown
fighting mode, which may include physical aggression; or they may opt
for approaches somewhere in between the fight-or-flee extremes of the
spectrum. Argumentation can be plausibly classified as an intermediary
response:



> 
> 
> [A]rgument literally is a form of pacifism--we are using words
> instead of swords to settle our disputes. With argument, we settle our
> disputes in ways that are most respectful of those who
> disagree--we do not buy them off, we do not threaten them, and we
> do not beat them into submission. Instead, we give them reasons that
> bear on the truth or falsity of their beliefs. However adversarial
> argument may be, it isn't bombing. [...] argument is a
> pacifistic replacement for truly violent solutions to
> disagreements.... (Aikin 2011: 256)
> 
> 
> 



This is not to say that argumentation will always or even typically be
the best approach to handle conflict and disagreement; the point is
rather that argumentation at least has the potential to do so,
provided that the background conditions are suitable and that
provisions to mitigate escalation are in place (Aikin 2011). Versions
of this view can be found in the work of proponents of agonistic
conceptions of democracy and political deliberation (Wenman 2013; see
entry on
 feminist political philosophy).
 For agonist thinkers, conflict and strife are inevitable features of
human lives, and so cannot be eliminated; but they can be managed. One
of them is Chantal Mouffe (Mouffe 2000), for whom democratic
practices, including argumentation/deliberation, can serve to contain
hostility and transform it into more constructive forms of contest.
However, it is far from obvious that argumentation by itself will
suffice to manage conflict; typically, other kinds of intervention
must be involved (Young 2000), as the risk of argumentation being used
to exercise power rather than as a tool to manage conflict always
looms large (van Laar & Krabbe 2019).


### 3.5 Conclusion



From these observations on different types of argumentation, a
pluralistic picture emerges: argumentation, understood as the exchange
of reasons to justify claims, seems to have different applications in
different situations. However, it is not clear that some of the goals
often attributed to argumentation such as epistemic improvement and
reaching consensus can in fact be reliably achieved in many real life
situations. Does this mean that argumentation is useless and futile?
Not necessarily, but it may mean that engaging in argumentation will
not always be the optimal response in a number of contexts.


## 4. Argumentation Across Fields of Inquiry and Social Practices



Argumentation is practiced and studied in many fields of inquiry;
philosophers interested in argumentation have much to benefit from
engaging with these bodies of research as well.


### 4.1 Argumentation theory



To understand the emergence of argumentation theory as a specific
field of research in the twentieth century, a brief discussion of
preceding events is necessary. In the nineteenth century, a number of
textbooks aiming to improve everyday reasoning via public education
emphasized logical and rhetorical concerns, such as those by Richard
Whately (see entry on
 fallacies).
 As noted in
 section 3.2,
 John Stuart Mill also had a keen interest in argumentation and its
role in public discourse (Mill 1859), as well as an interest in logic
and reasoning (see entries on
 Mill
 and on
 fallacies).
 But with the advent of mathematical logic in the final decades of the nineteenth century,
logic and the study of ordinary, everyday argumentation came apart, as
logicians such as Frege, Hilbert, Russell etc. were primarily
interested in *mathematical* reasoning and argumentation. As a
result, their logical systems are not particularly suitable to study
everyday argumentation, as this is simply not what they were designed
to
 do.[6]



Nevertheless, in the twentieth century a number of authors took
inspiration from developments in formal logic and expanded the use of
logical tools to the analysis of ordinary argumentation. A pioneer in
this tradition is Susan Stebbing, who wrote what can be seen as the
first textbook in analytic philosophy, and then went on to write a
number of books aimed at a general audience addressing everyday and
public discourse from a philosophical/logical perspective (see entry
on
 Susan Stebbing).
 Her 1939 book *Thinking to Some Purpose*, which can be
considered as one of the first textbooks in critical thinking, was
widely read at the time, but did not become particularly influential
for the development of argumentation theory in the decades to
follow.



By contrast, Stephen Toulmin's 1958 book *The Uses of
Argument* has been tremendously influential in a wide range of
fields, including critical thinking education, rhetoric, speech
communication, and computer science (perhaps even more so than in
Toulmin's own original field, philosophy). Toulmin's aim
was to criticize the assumption (widely held by Anglo-American
philosophers at the time) that any significant argument can be
formulated in purely formal, deductive terms, using the formal logical
systems that had emerged in the preceding decades (see (Eemeren,
Garssen, et al. 2014: ch. 4). While this critique was met with much
hostility among fellow philosophers, it eventually gave rise to an
alternative way of approaching argumentation, which is often described
as "informal logic" (see entry on
 informal logic).
 This approach seeks to engage and analyze instances of argumentation
in everyday life; it recognizes that, while useful, the tools of
deductive logic alone do not suffice to investigate argumentation in
all its complexity and pragmatic import. In a similar vein, Charles
Hamblin's 1970 book *Fallacies* reinvigorated the study
of fallacies in the context of argumentation by re-emphasizing
(following Aristotle) the importance of a dialectical-dialogical
background when reflecting on fallacies in argumentation (see entry on
 fallacies).



Around the same time as Toulmin, Chaim Perelman and Lucie
Olbrechts-Tyteca were developing an approach to argumentation that
emphasized its persuasive component. To this end, they turned to
classical theories of rhetoric, and adapted them to give rise to what
they described as the "New Rhetoric". Their book
*Traite de l'argumentation: La nouvelle
rhetorique* was published in 1958 in French, and translated
into English in 1969. Its key idea: 



> 
> 
> since argumentation aims at securing the adherence of those to whom it
> is addressed, it is, in its entirety, relative to the audience to be
> influenced. (Perelman & Olbrechts-Tyteca 1958 [1969: 19]) 
> 
> 
> 



They introduced the influential distinction between *universal*
and *particular* audiences: while every argument is directed at
a specific individual or group, the concept of a universal audience
serves as a normative ideal encapsulating shared standards of
agreement on what counts as legitimate argumentation (see Eemeren,
Garssen, et al. 2014: ch. 5).



The work of these pioneers provided the foundations for subsequent
research in argumentation theory. One approach that became influential
in the following decades is the pragma-dialectics tradition developed
by Frans van Eemeren and Rob Grootendorst (Eemeren & Grootendorst
1984, 2004). They also founded the journal *Argumentation*, one
of the flagship journals in argumentation theory. Pragma-dialectics
was developed to study argumentation as a discourse activity, a
complex speech act that occurs as part of interactional linguistic
activities with specific communicative goals ("pragma"
refers to the functional perspective of goals, and
"dialectic" to the interactive component). For these
authors, argumentative discourse is primarily directed at the
reasonable resolution of a difference of opinion. Pragma-dialectics
has a descriptive as well as a normative component, thus offering
tools both for the analysis of concrete instances of argumentation and
for the evaluation of argumentation correctness and success (see
Eemeren, Garssen, et al. 2014: ch. 10).



Another leading author in argumentation theory is Douglas Walton, who
pioneered the argument schemes approach to argumentation that borrows
tools from formal logic but expands them so as to treat a wider range
of arguments than those covered by traditional logical systems
(Walton, Reed, & Macagno 2008). Walton also formulated an
influential account of argumentation in dialogue in collaboration with
Erik Krabbe (Walton & Krabbe 1995). Ralph Johnson and Anthony
Blair further helped to consolidate the field of argumentation theory
and informal logic by founding the Centre for Research in Reasoning,
Argumentation, and Rhetoric in Windsor (Ontario, Canada), and by
initiating the journal *Informal Logic*. Their textbook
*Logical Self-Defense* (Johnson & Blair 1977) has also been
particularly influential.


### 4.2 Artificial intelligence and computer science



The study of argumentation within computer science and artificial
intelligence is a thriving field of research, with dedicated journals
such as *Argument and Computation* and regular conference
series such as COMMA (International Conference on Computational Models
of Argument; see Rahwan & Simari 2009 and Eemeren, Garssen, et al.
2014: ch. 11 for overviews).



The historical roots of argumentation research in artificial
intelligence can be traced back to work on non-monotonic logics (see
entry on
 non-monotonic logics)
 and defeasible reasoning (see entry on
 defeasible reasoning).
 Since then, three main different perspectives have emerged (Eemeren,
Garssen, et al. 2014: ch. 11): the theoretical systems perspective,
where the focus is on theoretical and formal models of argumentation
(following the tradition of philosophical and formal logic); the
artificial systems perspective, where the aim is to build computer
programs that model or support argumentative tasks, for instance, in
online dialogue games or in expert systems; the natural systems
perspective, which investigates argumentation in its natural form with
the help of computational tools (e.g., argumentation mining [Peldszus
& Stede 2013; Habernal & Gurevych 2017], where computational
methods are used to identify argumentative structures in large corpora
of texts).



An influential approach in this research tradition is that of
*abstract argumentation frameworks*, initiated by the
pioneering work of Dung (1995). Before that, argumentation in AI was
studied mostly under the inspiration of concepts coming from informal
logic such as argumentation schemes, context, stages of dialogues and
argument moves. By contrast, the key notion in the framework proposed
by Dung is that of *argument attack*, understood as an abstract
formal relation roughly intended to capture the idea that it is
possible to challenge an argument by means of another argument
(assertions are understood as a special case of arguments with zero
premises). Arguments can then be represented in networks of attacks
and defenses: an argument *A* can attack an argument *B*,
and *B* in turn may attack further arguments *C* and
*D* (the connection with the notion of *defeaters* is a
natural one, which Dung also addresses).



Besides abstract argumentation, three other important lines of
research in AI are: the (internal) structure of arguments;
argumentation in multi-agent systems; applications to specific tasks
and domains (Rahwan & Siwari 2009). The structural approach
investigates formally features such as argument strength/force (e.g.,
a conclusive argument is stronger than a defeasible argument),
argument schemes (Bex, Prakken, Reed, & Walton 2003) etc.
Argumentation in multi-agent systems is a thriving subfield with its
own dedicated conference series (ArgMAS), based on the recognition
that argumentation is a particularly suitable vehicle to facilitate
interaction in the artificial environments studied by AI researchers
working on multi-agent systems (see a special issue of the journal
*Argument & Computation* [Atkinson, Cerutti, et al. 2016]).
Finally, computational approaches in argumentation have also thrived
with respect to specific domains and applications, such as legal
argumentation (Prakken & Sartor 2015). Recently, as a reaction to
the machine-learning paradigm, the idea of explainable AI has gotten
traction, and the concept of argumentation is thought to play a
fundamental role for explainable AI (Sklar & Azhar 2018).


### 4.3 Cognitive science and psychology



Argumentation is also an important topic of investigation within
cognitive science and psychology. Researchers in these fields are
predominantly interested in the descriptive question of how people in
fact engage in argumentation, rather than in the normative question of
how they ought to do it (although some of them have also drawn
normative conclusions, e.g., Hahn & Oaksford 2006; Hahn &
Hornikx, 2016). Controlled experiments are one of the ways in which the descriptive question can be investigated.



Systematic research specifically on *argumentation* within
cognitive science and psychology has significantly increased over the
last 10 years. Before that, there had been extensive research on
reasoning conceived as an individual, internal process, much of which
had been conducted using task materials such as syllogistic arguments
(Dutilh Novaes 2020b). But due to what may be described as an
individualist bias in cognitive science and psychology (Mercier 2018),
these researchers did not draw explicit connections between their
findings and the public acts of "giving and asking for
reasons". It is only somewhat recently that argumentation began
to receive sustained attention from these researchers. The
investigations of Hugo Mercier and colleagues (Mercier & Sperber
2017; Mercier 2018) and of Ulrike Hahn and colleagues (Hahn &
Oaksford 2007; Hornikx & Hahn 2012; Collins & Hahn 2018) have
been particularly influential. (See also Paglieri, Bonelli, &
Felletti 2016, an edited volume containing a representative overview
of research on the psychology of argumentation.) Another interesting
line of research has been the study of the development of reasoning
and argumentative skills in young children (Koymen, Mammen, &
Tomasello 2016; Koymen & Tomasello 2020).



Mercier and Sperber defend an interactionist account of reasoning,
according to which the primary function of reasoning is for social
interactions, where reasons are exchanged and receivers of reasons
decide whether they find them convincing--in other words, for
argumentation (Mercier & Sperber 2017). They review a wealth of
evidence suggesting that reasoning is rather flawed when it comes to
drawing conclusions from premises in order to expand one's
knowledge. From this they conclude, on the basis of evolutionary
arguments, that the function of reasoning must be a different one,
indeed one that responds to features of human sociality and the need
to exercise epistemic vigilance when receiving information from
others. This account has inaugurated a rich research program which they have been pursuing with colleagues for over
a decade now, and which has delivered some interesting results--for
example, that we seem to be better at evaluating the quality of
arguments proposed by others than at formulating high-quality arguments
ourselves (Mercier 2018).



In the context of the Bayesian (see entry on
 Bayes' theorem)
 approach to reasoning that was first developed by Mike Oaksford and
Nick Chater in the 1980s (Oaksford & Chater 2018), Hahn and
colleagues have extended the Bayesian framework to the investigation
of argumentation. They claim that Bayesian probabilities offer an
accurate descriptive model of how people evaluate the strength of
arguments (Hahn & Oaksford 2007) as well as a solid perspective to
address normative questions pertaining to argument strength (Hahn
& Oaksford 2006; Hahn & Hornikx 2016). The Bayesian approach
allows for the formulation of probabilistic measures of argument
strength, showing that many so-called "fallacies" may
nevertheless be good arguments in the sense that they considerably
raise the probability of the conclusion. For example, deductively
invalid argument schemes (such as affirming the consequent (AC) and
denying the antecedent (DA)) can also provide considerable support for
a conclusion, depending on the contents in question. The extent to
which this is the case depends primarily on the specific informational
context, captured by the prior probability distribution, not on the
structure of the argument. This means that some instances of, say, AC,
may offer support to a conclusion while others may fail to do so (Eva
& Hartmann 2018). Thus seen, Bayesian argumentation represents a
significantly different approach to argumentation from those inspired
by logic (e.g., argument schemes), but they are not necessarily incompatible;
they may well be complementary perspectives (see also [Zenker
2013]).


### 4.4 Language and communication



Argumentation is primarily (though not exclusively) a linguistic
phenomenon. Accordingly, argumentation is extensively studied in
fields dedicated to the study of language, such as rhetoric,
linguistics, discourse analysis, communication, and pragmatics, among
others (see Eemeren, Garssen, et al. 2014: chs 8 and 9). Researchers
in these areas develop general theoretical models of argumentation and
investigate concrete instances of argumentation in specific domains on
the basis of linguistic corpora, discourse analysis, and other methods
used in the language sciences (see the edited volume Oswald, Herman,
& Jacquin [2018] for a sample of the different lines of research).
Overall, research on argumentation within the language sciences tends
to focus primarily on concrete occurrences of arguments in a variety
of domains, adopting a largely descriptive rather than normative
perspective (though some of these researchers also tackle normative
considerations).



Some of these analyses approach arguments and argumentation primarily
as text or self-contained speeches, while others emphasize the
interpersonal, communicative nature of "face-to-face"
argumentation (see Eemeren, Garssen, et al. 2014: section 8.9). One
prominent approach in this tradition is due to communication scholars
Sally Jackson and Scott Jacobs. They have drawn on speech act theory
and conversation analysis to investigate argumentation as a
disagreement-relevant expansion of speech acts that, through mutually
recognized reasons, allows us to manage disagreements despite the
challenges they pose for communication and coordination of activities
(Jackson & Jacobs 1980; Jackson 2019). Moreover, they perceive
institutionalized practices of argumentation and concrete
"argumentation designs"--such as for example
randomized controlled trials in medicine--as interventions aimed
at improving methods of disagreement management through
argumentation.



Another communication scholar, Dale Hample, has further argued for the
importance of approaching argumentation as an essentially
interpersonal communicative activity (Hample 2006, 2018). This
perspective allows for the consideration of a broader range of
factors, not only the arguments themselves but also (and primarily)
the people involved in those processes: their motivations,
psychological processes, and emotions. It also allows for the
formulation of questions pertaining to individual as well as cultural
differences in argumentative styles (see
 section 5.3
 below).



Another illuminating perspective views argumentative practices as
inherently tied to broader socio-cultural contexts (Amossy 2009). The
*Journal of Argumentation in Context* was founded in 2012
precisely to promote a contextual approach to argumentation. Once
argumentation is no longer only considered in abstraction from
concrete instances taking place in real-life situations, it becomes
imperative to recognize that argumentation does not take place in a
vacuum; typically, argumentative practices are embedded in other kinds
of practices and institutions, against the background of specific
socio-cultural, political structures. The method of discourse analysis
is particularly suitable for a broader perspective on argumentation,
as shown by the work of Ruth Amossy (2002) and Marianne Doury (2009),
among others.


### 4.5 Argumentation in specific social practices



Argumentation is crucial in a number of specific organized social
practices, in particular in politics, science, law, and education. The
relevant argumentative practices are studied in each of the
corresponding knowledge domains; indeed, while some general principles
may govern argumentative practices across the board, some may be
specific to particular applications and domains.



As already mentioned, argumentation is typically viewed as an
essential component of political democratic practices, and as such it
is of great interest to political scientists and political theorists
(Habermas 1992 [1996]; Young 2000; Landemore 2013; Fishkin 2016; see
entry on
 democracy).
 (The term typically used in this context is
"deliberation" instead of "argumentation", but
these can be viewed as roughly synonymous for our purposes.) General
theories of argumentation such as pragma-dialectic and the Toulmin
model can be applied to political argumentation with illuminating
results (Wodak 2016; Mohammed 2016). More generally, political
discourse seems to have a strong argumentative component, in
particular if argumentation is understood more broadly as not only
pertaining to rational discourse (*logos*) but as also
including what rhetoricians refer to as *pathos* and
*ethos* (Zarefsky 2014; Amossy 2018). But critics of
argumentation and deliberation in political contexts also point out
the limitations of the classical deliberative model (Sanders 1997;
Talisse 2019).



Moreover, scientific communities seem to offer good examples of
(largely) well-functioning argumentative practices. These are
disciplined systems of collective epistemic activity, with tacit but
widely endorsed norms for argumentative engagement for each domain
(which does not mean that there are not disagreements on these very
norms). The case of mathematics has already been mentioned above:
practices of mathematical proof are quite naturally understood as
argumentative practices (Dutilh Novaes 2020a). Furthermore, when a
scientist presents a new scientific claim, it must be backed by
arguments and evidence that her peers are likely to find convincing,
as they follow from the application of widely agreed-upon scientific
methods (Longino 1990; Weinstein 1990; Rehg 2008; see entry on the
 social dimensions of scientific knowledge).
 Other scientists will in turn critically examine the evidence and
arguments provided, and will voice objections or concerns if they find
aspects of the theory to be insufficiently convincing. Thus seen,
science may be viewed as a "game of giving and asking for
reasons" (Zamora Bonilla 2006). Certain features of scientific
argumentation seem to ensure its success: scientists see other
scientists as prima facie peers, and so (typically at least) place a
fair amount of trust in other scientists by default; science is based
on the principle of "organized skepticism" (a term
introduced by the pioneer sociologist of science Robert Merton [Merton, 1942]), which
means that asking for further reasons should not be perceived as a
personal attack. These are arguably aspects that distinguish
argumentation in science from argumentation in other domains in virtue
of these institutional factors (Mercier & Heintz 2014). But
ultimately, scientists are part of society as a whole, and thus the
question of how scientific and political argumentation intersect
becomes particularly relevant (Kitcher 2001).



Another area where argumentation is essential is the law, which also
corresponds to disciplined systems of collective activity with rules
and principles for what counts as acceptable arguments and evidence.
 
In litigation (in particular in adversarial justice systems), there
are typically two sides disagreeing on what is lawful or just, and the
basic idea is that each side will present its strongest arguments; it
is the comparison between the two sets of arguments that should lead
to the best judgment (Walton 2002). Legal reasoning and argumentation
have been extensively studied within jurisprudence for decades, in
particular since Ronald Dworkin's (1977) and Neil
MacCormick's (1978) responses to HLA Hart's highly
influential *The Concept of Law* (1961). A number of other
views and approaches have been developed, in particular from the
perspectives of natural law theory, legal positivism, common law, and
rhetoric (see Feteris 2017 for an overview). Overall, legal
argumentation is characterized by extensive uses of analogies (Lamond
2014), abduction (Askeland 2020), and defeasible/non-monotonic
reasoning (Bex & Verheij 2013). An interesting question is whether
argumentation in law is fundamentally different from argumentation in
other domains, or whether it follows the same overall canons and norms
but applied to legal topics (Raz 2001).



Finally, the development of argumentative skills is arguably a
fundamental aspect of (formal) education (Muller Mirza &
Perret-Clermont 2009). Ideally, when presented with arguments, a
learner should not simply accept what is being said at face value, but
should instead reflect on the reasons offered and come to her own
conclusions. Argumentation thus fosters independent, critical
thinking, which is viewed as an important goal for education (Siegel
1995; see entry on
 critical thinking).
 A number of education theorists and developmental psychologists have
empirically investigated the effects of emphasizing argumentative
skills in educational settings, with encouraging results (Kuhn &
Crowell 2011). There has been in particular much emphasis on
argumentation specifically in *science* education, based on the
assumption that argumentation is a key component of scientific
practice (as noted above); the thought is that this feature of
scientific practice should be reflected in science education (Driver,
Newton, & Osborne 2000; Erduran & Jimenez-Aleixandre
2007).


## 5. Further Topics



Argumentation is a multi-faceted phenomenon, and the literature on
arguments and argumentation is massive and varied. This entry can only
scratch the surface of the richness of this material, and many
interesting, relevant topics must be left out for reasons of space. In
this final section, a selection of topics that are likely to attract
considerable interest in future research are discussed.


### 5.1 Argumentative injustice and virtuous argumentation



In recent years, the concept of epistemic injustice has received much
attention among philosophers (Fricker 2007; McKinnon 2016). Epistemic
injustice occurs when a person is unfairly treated qua knower on the
basis of prejudices pertaining to social categories such as gender,
race, class, ability etc. (see entry on
 feminist epistemology and philosophy of science).
 One of the main categories of epistemic injustice discussed
in the literature pertains to testimony and is known as *testimonial
injustice*: this occurs when a testifier is not given a degree of
credibility commensurate to their actual expertise on the relevant
topic, as a result of prejudice. (Whether credibility excess is also a
form of testimonial injustice is a moot point in the literature
[Medina 2011].)



Since argumentation can be viewed as an important mechanism for
sharing knowledge and information, i.e., as having significant
epistemic import (Goldman 2004), the question arises whether there
might be instances of epistemic injustice pertaining specifically to
argumentation, which may be described as *argumentative
injustice*, and which would be notably different from other
recognized forms of epistemic injustice such as testimonial injustice.
Bondy (Bondy 2010) presented a first articulation of the notion of
argumentative injustice, modeled after Fricker's notion of
epistemic injustice and relying on a broadly epistemological
conception of argumentation. However, Bondy's analysis does not
take into account some of the structural elements that have become
central to the analysis of epistemic injustice since Fricker's
influential work, so it seems further discussion of epistemic
injustice in argumentation is still needed. For example, in situations
of disagreement, epistemic injustice can give rise to further
obstacles to rational argumentation, leading to deep disagreement
(Lagewaard 2021).



Moreover, as often noted by critics of adversarial approaches,
argumentation can also be used as an instrument of domination and
oppression used to overpower and denigrate an interlocutor (Nozick
1981), especially an interlocutor of "lower" status in the
context in question (Moulton 1983; see entry on
 feminist approaches to argumentation).
 From this perspective, it is clear that argumentation may also be
used to reinforce and exacerbate injustice, inequalities and power
differentials (Goodwin 2007). Given this possibility, and in response
to the perennial risk of excessive aggressiveness in argumentative
situations, a normative account of how argumentation *ought* to
be conducted so as to avoid these problematic outcomes seem to be
required.



One such approach is *virtue argumentation theory*. Drawing on
virtue ethics and virtue epistemology (see entries on
 virtue ethics
 and
 virtue epistemology),
 virtue argumentation theory seeks to theorize how to argue well in
terms of the dispositions and character of arguers rather than, for
example, in terms of properties of arguments considered in abstraction
from arguers (Aberdein & Cohen 2016). Some of the argumentative
virtues identified in the literature are: willingness to listen to
others (Cohen 2019), willingness to take a novel viewpoint seriously
(Kwong 2016), humility (Kidd 2016), and open-mindedness (Tanesini
2020).



By the same token, defective argumentation is conceptualized not
(only) in terms of structural properties of arguments (e.g.,
fallacious argument patterns), but in terms of the vices displayed by
arguers such as arrogance and narrow-mindedness, among others
(Aberdein 2016). Virtue argumentation theory now constitutes a vibrant
research program, as attested by a special issue of *Topoi*
dedicated to the topic (see [Aberdein & Cohen 2016] for its Introduction). It allows for
a reconceptualization of classical themes within argumentation theory
while also promising to provide concrete recommendations on how to
argue better. Whether it can fully counter the risk of epistemic
injustice and oppressive uses of argumentation is however debatable,
at least as long as broader structural factors related to power
dynamics are not sufficiently taken into account (Kukla 2014).


### 5.2 Emotions and argumentation



On some idealized construals, argumentation is conceived as a purely
rational, emotionless endeavor. But the strong connection between
argumentative activities and emotional responses has also long been
recognized (in particular in rhetorical analyses of argumentation),
and more recently has become the object of extensive research (Walton
1992; Gilbert 2004; Hample 2006: ch. 5). Importantly, the recognition
of a role for emotions in argumentation does not entail a complete
rejection of the "rationality" of argumentation; rather,
it is based on the rejection of a strict dichotomy between reason and
emotion (see entry on
 emotion),
 and on a more encompassing conception of argumentation as a
multi-layered human activity.



Rather than dispassionate exchanges of reasons, instances of
argumentation typically start against the background of existing
emotional relations, and give rise to further affective
responses--often, though not necessarily, negative responses of
aggression and hostility. Indeed, it has been noted that, by itself,
argumentation can give rise to conflict and friction where there was
none to be found prior to the argumentative engagement (Aikin 2011).
This occurs in particular because critical engagement and requests for
reasons are at odds with default norms of credulity in most mundane
dialogical interactions, thus creating a perception of antagonism. But
argumentation may also give rise to positive affective responses if
the focus is on coalescence and cooperation rather than on hostility
(Gilbert 1997).



The descriptive claim that instances of argumentation are typically
emotionally charged is not particularly controversial, though it
deserves to be further investigated; the details of affective
responses during instances of argumentation and how to deal with them
are non-trivial (Krabbe & van Laar 2015). What is potentially more
controversial is the *normative* claim that instances of
argumentation *may* or *should* be emotionally charged,
i.e., that emotions may or ought to be involved in argumentative
processes, even if it may be necessary to regulate them in such
situations rather than giving them free rein (Gonzalez,
Gomez, & Lemos 2019). The significance of emotions for
persuasion has been recognized for millennia (see entry on
 Aristotle's rhetoric),
 but more recently it has become clear that emotions also have a
fundamental role to play for choices of what to focus on and what to
care about (Sinhababu 2017). This general point seems to apply to
instances of argumentation as well. For example, Howes and Hundleby
(Howes & Hundleby 2018) argue that, contrary to what is often
thought, anger can in fact make a positive contribution to
argumentative encounters. Indeed, anger may have an important
epistemological role in such encounters by drawing attention to
relevant premises and information that may otherwise go unnoticed.
(They recognize that anger may also derail argumentation when the
encounter becomes a full-on confrontation.)



In sum, the study of the role of emotions for argumentation, both
descriptively and normatively speaking, has attracted the interest of
a number of scholars, traditionally in connection with rhetoric and
more recently also from the perspective of argumentation as
interpersonal communication (Hample 2006). And yet, much work remains
to be done on the significance of emotions for argumentation, in
particular given that the view that argumentation should be a purely
rational, dispassionate endeavor remains widely (even if tacitly)
endorsed.


### 5.3 Cross-cultural perspectives on argumentation



Once we adopt the perspective of argumentation as a communicative
practice, the question of the influence of cultural factors on
argumentative practices naturally arises. Is there significant
variability in how people engage in argumentation depending on their
sociocultural backgrounds? Or is argumentation largely the same
phenomenon across different cultures? Actually, we may even ask
ourselves whether argumentation in fact occurs in all human cultures,
or whether it is the product of specific, contingent background
conditions, thus not being a human universal. For comparison: it had
long been assumed that practices of counting were present in all human
cultures, even if with different degrees of complexity. But in recent
decades it has been shown that some cultures do not engage
systematically in practices of counting and basic arithmetic at all,
such as the Piraha in the Amazon (Gordon 2004; see entry on
 culture and cognitive science).
 By analogy, it seems that the purported universality of argumentative
practices should not be taken for granted, but rather be treated as a
legitimate empirical question. (Incidentally, there is some anecdotal
evidence that the Piraha themselves engage in argumentative
exchanges [Everett 2008], but to date their argumentative skills have
not been investigated systematically, as is the case with their
numerical skills.)



Of course, how widespread argumentative practices will be also depends
on how the concept of "argumentative practices" is defined
and operationalized in the first place. If it is narrowly defined as
corresponding to regimented practices of reason-giving requiring clear
markers and explicit criteria for what counts as premises, conclusions
and relations of support between them, then argumentation may well be
restricted to cultures and subcultures where such practices have been
explicitly codified. By contrast, if argumentation is defined more
loosely, then a wider range of communicative practices will be
considered as instances of argumentation, and thus presumably more
cultures will be found to engage in (what is thus viewed as)
argumentation. This means that the spread of argumentative practices
across cultures is not only an empirical question; it also requires
significant conceptual input to be addressed.



But if (as appears to be the case) argumentation is not a strictly
WEIRD phenomenon, restricted to Western, Educated, Industrialized,
Rich, and Democratic societies (Henrich, Heine, & Norenzayan
2010), then the issue of cross-cultural variability in argumentative
practices gives rise to a host of research questions, again both at
the descriptive and at the normative level. Indeed, even if at the
descriptive level considerable variability in argumentative practices
is identified, the normative question of whether there should be
universally valid canons for argumentation, or instead specific norms
for specific contexts, remains pressing. At the descriptive level, a
number of researchers have investigated argumentative practices in
different WEIRD as well as non-WEIRD cultures, also addressing
questions of cultural variability (Hornikx & Hoeken 2007; Hornikx
& de Best 2011).



A foundational work in this context is Edwin Hutchins' 1980 book
*Culture and Inference*, a study of the Trobriand
Islanders' system of land tenure in Papua New Guinea (Hutchins
1980). While presented as a study of inference and reasoning among the
Trobriand Islanders, what Hutchins in fact investigated were instances
of legal argumentation in land courts by means of ethnographic
observation and interviews with litigants. This led to the formulation
of a set of twelve basic propositions codifying knowledge about land
tenure, as well as transfer formulas governing how this knowledge can
be applied to new disputes. Hutchins' analysis showed that the
Trobriand Islanders had a sophisticated argumentation system to
resolve issues pertaining to land tenure, in many senses resembling
argumentation and reasoning in so-called WEIRD societies in that it
seemed to recognize as valid simple logical structures such as
*modus ponens* and *modus tollens*.



More recently, Hugo Mercier and colleagues have been conducting
studies in countries such as Japan (Mercier, Deguchi, Van der Henst,
& Yama 2016) and Guatemala (Castelain, Girotto, Jamet, &
Mercier 2016). While recognizing the significance and interest of
cultural differences (Mercier 2013), Mercier maintains that
argumentation is a human universal, as argumentative capacities and
tendencies are a result of natural selection, genetically encoded in
human cognition (Mercier 2011; Mercier & Sperber 2017). He takes
the results of the cross-cultural studies conducted so far as
confirming the universality of argumentation, even considering
cultural differences (Mercier 2018).



Another scholar who has been carrying out an extensive research
program on cultural differences in argumentation is communication
theorist Dale Hample. With different sets of colleagues, he has
conducted studies by means of surveys where participants (typically,
university undergraduates) self-report on their argumentative
practices in countries such as China, Japan, Turkey, Chile, the
Netherlands, Portugal, the United States (among others; Hample 2018:
ch. 7). His results overall show a number of similarities, which may
be partially explained by the specific demographic (university
students) from which participants are usually recruited. But
interesting differences have also been identified, for example
different levels of willingness to engage in argumentative
encounters.



In a recent book (Tindale 2021), philosopher Chris Tindale adopts an
anthropological perspective to investigate how argumentative practices
emerge from the experiences of peoples with diverse backgrounds. He
emphasizes the argumentative roles of place, orality, myth, narrative,
and audience, also assessing the impacts of colonialism on the study
of argumentation. Tindale reviews a wealth of anthropological and
ethnographic studies on argumentative practices in different cultures,
thus providing what is to date perhaps the most comprehensive study on
argumentation from an anthropological perspective.



On the whole, the study of differences and commonalities in
argumentative practices across cultures is an established line of
research on argumentation, but arguably much work remains to be done
to investigate these complex phenomena more thoroughly.


### 5.4 Argumentation and the Internet



So far we have not yet considered the question of the different media
through which argumentation can take place. Naturally, argumentation
can unfold orally in face-to-face encounters--discussions in
parliament, political debates, in a court of law--as well as in
writing--in scientific articles, on the Internet, in newspaper
editorials. Moreover, it can happen synchronically, with real-time
exchanges of reasons, or asynchronically. While it is reasonable to
expect that there will be some commonalities across these different
media and environments, it is also plausible that specific features of
different environments may significantly influence how argumentation
is conducted: different environments present different kinds of
*affordances* for arguers (Halpern & Gibbs 2013; Weger
& Aakhus 2003; see entry on
 embodied cognition
 for the concept of affordance). Indeed, if the Internet represents a
fundamentally novel cognitive ecology (Smart, Heersmink, & Clowes
2017), then it will likely give rise to different forms of
argumentative engagement (Lewinski 2010). Whether these new forms
will represent *progress* (according to some suitable metric)
is however a moot point.



In the early days of the Internet in the 1990s, there was much hope
that online spaces would finally realize the Habermasian ideal of a
public sphere for political deliberation (Hindman 2009). The Internet
was supposed to act as the great equalizer in the worldwide
marketplace of ideas, finally attaining the Millian ideal of free
exchange of ideas (Mill 1859). Online, everyone's voice would
have an equal chance of being heard, everyone could contribute to the
conversation, and everyone could simultaneously be a journalist, news
consumer, engaged citizen, advocate, and activist.



A few decades later, these hopes have not really materialized. It is
probably true that most people now argue *more*--in social
media, blogs, chat rooms, discussion boards etc.--but it is much
less obvious that they argue *better*. Indeed, rather than
enhancing democratic ideals, some have gone as far as claiming that
instead, the Internet is "killing democracy" (Bartlett
2018). There is very little oversight when it comes to the spreading
of propaganda and disinformation online (Benkler, Faris, & Roberts
2018), which means that citizens are often being fed faulty
information and arguments. Moreover, it seems that online environments
may lead to increased polarization when polemic topics are being
discussed (Yardi & Boyd 2010), and to "intellectual
arrogance" (Lynch 2019). Some have argued that online
discussions lead to more overly emotional engagement when compared to
other forms of debate (Kramer, Guillory, & Hancock 2014). But not
everyone is convinced that the Internet has only made things worse
when it comes to argumentation, or in any case that it cannot be
suitably redesigned so as to foster rather than destroy democratic
ideals and deliberation (Sunstein 2017).



Be that as it may, the Internet is here to stay, and online
argumentation is a pervasive phenomenon that argumentation theorists
have been studying and will continue to study for years to come. In
fact, if anything, online argumentation is now *more often*
investigated empirically than other forms of argumentation, among
other reasons thanks to the development of argument mining techniques
(see
 section 4.2
 above) which greatly facilitate the study of large corpora of textual
material such as those produced by online discussions. Beyond the very
numerous specific case studies available in the literature, there have
been also attempts to reflect on the phenomenon of online
argumentation in general, for example in journal special issues
dedicated to argumentation in digital media such as in
*Argumentation and Advocacy* (Volume 47(2), 2010) and
*Philosophy & Technology* (Volume 30(2), 2017). However, a
systematic analysis of online argumentation and how it differs from
other forms of argumentation remains to be produced.


## 6. Conclusion



Argument and argumentation are multifaceted phenomena that have
attracted the interest of philosophers as well as scholars in other
fields for millennia, and continue to be studied extensively in
various domains. This entry presents an overview of the main strands
in these discussions, while acknowledging the impossibility of fully
doing justice to the enormous literature on the topic. But the
literature references below should at least provide a useful starting
point for the interested reader.