Argument map

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An argument map.

In informal logic and philosophy, an argument map is a visual representation of the structure of an argument. It includes the components of an argument such as a main contention, premises, co-premises, objections, rebuttals, and lemmas. Typically an argument map is a "box and arrow" diagram with boxes corresponding to propositions and arrows corresponding to relationships such as evidential support.

Argument maps are commonly used in the context of teaching and applying critical thinking.[1] The purpose of mapping is to uncover the logical structure of arguments, identify unstated assumptions, evaluate the support an argument offers for a conclusion, and aid understanding of debates. Argument maps are often designed to support deliberation of issues, ideas and arguments in wicked problems.

An argument map is not to be confused with a concept map or a mind map, which are less strict in relating claims.


This is a simple argument map. The conclusion is shown at the top, and the boxes linked to it represent supporting reasons, which comprise one or more premises. The reason, 1A, comprising two premises 1A-a and 1A-b, support the conclusion:


Here is a more complex map. The objection 1A weakens the conclusion, while the reason 2A supports premise 1A-b of the objection:

A sample argument using objections.

Evidence that argument mapping improves critical thinking ability[edit]

There is empirical evidence that the skills developed in argument-mapping-based critical thinking courses substantially transfer to critical thinking done without argument maps. Alvarez's meta-analysis found that such critical thinking courses produced gains of around 0.70 SD, about twice as much as standard critical-thinking courses.[2] The tests used in the reviewed studies were standard critical-thinking tests.

How argument mapping helps with critical thinking[edit]

The use of argument mapping has occurred within a number of disciplines, such as philosophy, management reporting, military and intelligence analysis, and public debates.

Logical structure: Argument maps display an argument's logical structure more clearly than does the standard linear way of presenting arguments.

Critical thinking concepts: In learning to argument map, students master such key critical thinking concepts as "reason", "objection", "premise", "conclusion", "inference", "rebuttal", "unstated assumption", "co-premise", "strength of evidence", "logical structure", "independent evidence", etc. Mastering such concepts is not just a matter of memorizing their definitions or even being able to apply them correctly; it is also understanding why the distinctions these words mark are important and using that understanding to guide one's reasoning.

Visualization: Humans are highly visual and argument mapping may provide students with a basic set of visual schemas with which to understand argument structures.

More careful reading and listening: Learning to argument map teaches people to read and listen more carefully, and highlights for them the key questions "What is the logical structure of this argument?" and "How does this sentence fit into the larger structure?" In-depth cognitive processing is thus more likely.

More careful writing and speaking: Argument mapping helps people to state their reasoning and evidence more precisely, because the reasoning and evidence must fit explicitly into the map's logical structure.

Literal and intended meaning: Often, many statements in an argument do not precisely assert what the author meant. Learning to argument map enhances the complex skill of distinguishing literal from intended meaning.

Externalization: Writing something down and reviewing what one has written often helps reveal gaps and clarify one's thinking. Because the logical structure of argument maps is clearer than that of linear prose, the benefits of mapping will exceed those or ordinary writing.

Anticipating replies: Important to critical thinking is anticipating objections and considering the plausibility of different rebuttals. Mapping develops this anticipation skill, and so improves analysis.

History and current applications[edit]


The philosophical origins and tradition of argument mapping[edit]

In the Elements of Logic, which was published in 1826 and issued in many subsequent editions,[3] Archbishop Richard Whately gave probably the first form of an argument map, introducing it with the suggestion that "many students probably will find it a very clear and convenient mode of exhibiting the logical analysis of the course of argument, to draw it out in the form of a Tree, or Logical Division".

From Whately's Elements of Logic p467, 1852 edition

However, the technique did not become widely used, possibly because for complex arguments, it involved much writing and rewriting of the premises.

Legal philosopher and theorist John Henry Wigmore produced maps of legal arguments using numbered premises in the early 20th century,[4] based in part on the ideas of 19th century philosopher Henry Sidgwick who used lines to indicate relations between terms.[5]

Wigmore evidence chart, from 1905

Stephen Toulmin, in a groundbreaking and influential book The Uses of Argument,[6] identified several elements to an argument which has been generalized. The Toulmin diagram is widely used in educational critical teaching.[7][8]

A Toulmin argument diagram, redrawn from his 1959 Uses of Argument
A generalised Toulmin diagram.

Anglophone argument diagramming in the 20th century[edit]

Dealing with the failure of formal reduction of informal argumentation, English speaking argumentation theory developed diagrammatic approaches to informal reasoning over a period of fifty years.

Michael Scriven developed an argument diagram in 1976.[9]

Scriven's argument diagram. The major premise 1 is conjoined with additional minor premises a and b to imply 2.

In 1988, David Kelley proposed a structured diagram technique with numbered premises, and arrows indicating inferential relations.[10] The premises were to be listed at the side of the diagram for reference. The three forms here of an argument are serial, additive (or joint), and non-additive (or convergent), respectively. Kelley also had divergent arguments, where a single premise could act as a reason for multiple lines of argument. Kelley diagrams are also often shown as "ball and stick" diagrams.

A Kelley argument diagram. The left argument is a "serial" argument, the middle is an "additive" argument, where multiple premises must be employed, and the right is a "disjunct" argument where several premises independently support a conclusion.

In the 1990s, Tim van Gelder developed a series of computer applications that permitted the premises to be fully stated and edited in the diagram, rather than in a legend.[11][12] This also permitted reasons to be edited for clarity according to the principle of charity, whereby one reconstructs arguments so they are consistent with the best interpretation of authorial intentions. The first program, Reason!Able, was superseded by two subsequent programs, bCisive and Rationale.[13] Rationale permits reasons comprising one or more premises.[12] This forces the arguer or analyst to identify the missing (unstated) premises based on the rule that there should be no danglers, that is, terms that only appear in one claim box of an argument (see Enthymeme). Here is a basic Rationale argument map:

A basic Rationale map

Reasons consist of premises that support a final or intermediate conclusion. In this map, premises 2A-a and 2A-b support the intermediate conclusion 1A-a, which is a co-premise with 1A-b for the final conclusion.

Argument maps can also map objections to conclusions or premises:

An argument map with objections to the final conclusion, and to one of the supporting premises.

In this map, objections are offered to premise 2A-b and also to the conclusion directly.

In 1998 a series of large-scale argument maps released by Robert E. Horn stimulated widespread interest in the technique.[14]

Difficulties with the philosophical tradition[edit]

It has traditionally been hard to separate teaching critical thinking from the philosophical tradition of teaching logic and method, and most critical thinking textbooks have been written by philosophers. Informal logic textbooks are replete with philosophical examples, but it is unclear whether the approach in such textbooks transfers to non-philosophy students.[7] There appears to be little statistical effect after such classes. Argument mapping, however, has a measurable effect according to many studies.[15] For example, instruction in argument mapping has been shown to improve the critical thinking skills of business students.[16]


Argument maps have been applied in many areas, but foremost in educational, academic and business settings.[17] It has also been proposed that argument mapping has a great potential to improve how we understand and execute democracy, in reference to the ongoing evolution of e-democracy.[18]


Argument Interchange Format[edit]

The Argument Interchange Format, AIF, is an international effort to develop a representational mechanism for exchanging argument resources between research groups, tools, and domains using a semantically rich language. AIF-RDF, is the extended ontology represented in the Resource Description Framework Schema (RDFS) semantic language. Though AIF is still something of a moving target, it is settling down.[19]

See the AIF original draft description (2006) and the full AIF-RDF ontology specifications in RDFS format.

Legal Knowledge Interchange Format[edit]

The Legal Knowledge Interchange Format (LKIF), developed in the European ESTRELLA project, is an XML schema for rules and arguments, designed with the goal of becoming a standard for representing and interchanging policy, legislation and cases, including their justificatory arguments, in the legal domain. LKIF builds on and uses the Web Ontology Language (OWL) for representing concepts and includes a reusable basic ontology of legal concepts.

See also[edit]



Further reading[edit]

External links[edit]

Argument mapping software[edit]

Online, collaborative software[edit]