Within Argument Map
Are These Reasons Independent or One Linked Argument?
Many apparent reasons fail because they only work together, not as separate support for a conclusion.
On this page
- Recognizing co premises
- Common mapping mistakes
- Testing combined support
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Introduction
One of the most common mistakes in analysing arguments is treating every stated reason as if it independently supports the conclusion. In reality, many arguments depend on linked premises—claims that only provide support when they are combined. If those premises are separated and counted as independent reasons, the argument can appear much stronger than it really is. Argument mapping helps reveal this problem by showing whether reasons stand alone or function as a single package. Researchers and argument-mapping guides commonly describe these connected claims as co-premises or dependent premises: neither premise does enough work on its own, but together they create the inference. [Wikipedia]WikipediaArgument mapArgument map
Understanding linked premises matters because many apparent examples of strong evidence are actually cases of false support patterns. The support seems substantial only because one argument has been mistakenly counted as several.
Are These Reasons Independent or One Linked Argument?
A useful test is to ask whether each premise would still provide meaningful support if the others disappeared.
Consider:
- All licensed surgeons have completed accredited surgical training.
- Dr Smith is a licensed surgeon.
- Therefore, Dr Smith completed accredited surgical training.
Neither premise independently establishes the conclusion. Knowing only that surgeons complete training does not tell us anything about Dr Smith. Knowing only that Dr Smith is a surgeon does not establish the training requirement. The support arises from the combination. This is a linked argument. [2jan.ucc.nau.edu]jan.ucc.nau.edu4: Independent and Linked PremisesIn contrast to independent premises, linked premises work together to reach a conclusion. Consider the…
Now compare:
- Three independent audits found accounting errors.
- The regulator identified accounting errors.
- Former employees reported accounting errors.
- Therefore, accounting errors likely occurred.
Each reason retains some force even if the others are removed. The argument contains multiple independent lines of support rather than one linked chain. Argument-mapping literature often calls this a convergent structure. [Wikipedia]WikipediaArgument mapArgument map CliffsNotes The distinction is not merely technical. It changes how much evidence the argument actually contains. [cliffsnotes.com]cliffsnotes.com□ Independent premises: Use separate arrows to maintainCliffsNotesMastering Argument Mapping: A Guide to Analyzing ComplexArgument Mapping Rules: ○ Mapping Rules: □ Co-premises: Join together…
Recognising Co-Premises
Linked premises usually display one of three patterns.
A general rule plus a specific case
- All members of group X have property Y.
- Object A belongs to group X.
- Therefore, object A has property Y.
This structure is common in everyday reasoning and formal logic alike. Neither statement works properly without the other. [philosophy.hku.hk]philosophy.hku.hkA10] Argument mappingNote that the two premises are connected together before linking to the conclusion. This merging of the links indic…
Evidence plus a connecting assumption
- This policy increased test scores in another school.
- The schools are relevantly similar.
- Therefore, the policy will increase scores here.
People often state the evidence but leave the connecting assumption unstated. The support exists only if both parts are accepted. Argument-mapping researchers note that hidden co-premises and unstated warrants frequently carry the real burden of persuasion. [YouTube]youtube.comArgument Mapping: Understanding and Making Arguments w…Nate Otey from ThinkerAnalytix visits The Stoa to discuss argument mappi…
Multiple incomplete facts that become persuasive only together
- The suspect’s fingerprints were on the safe.
- The suspect had access to the building during the relevant period.
- Therefore, the suspect may have opened the safe.
Either fact alone is weak. Together they create a stronger inference.
In maps, these claims are usually joined before connecting to the conclusion, signalling that they operate as a single reason rather than separate reasons. [philosophy.hku.hk]philosophy.hku.hkA10] Argument mappingThis merging of the links indicate that the two premises are co-premises which work together in a single argument t… [Quizlet]quizlet.comWeek 6Argument Mapping FlashcardsIn argument maps, we depict co-premises by linking the arrows joining them to the conclusion using a "Y" shape…
Common Mapping Mistakes
Counting one argument several times
A frequent error is to draw separate arrows from each linked premise to the conclusion. This accidentally transforms one argument into multiple arguments.
Suppose someone argues:
- The witness was present at the scene.
- The witness had a clear view.
- Therefore, the witness’s identification is reliable.
If each premise is mapped independently, the diagram falsely suggests two separate reasons for reliability. Yet presence alone does not establish reliability, and a clear view without presence is impossible. The support is joint rather than independent. [philosophy.hku.hk]philosophy.hku.hkA10] Argument mappingNote that the two premises are connected together before linking to the conclusion. This merging of the links indic…
This mistake inflates the apparent strength of the case because readers unconsciously count each arrow as additional evidence.
Missing a hidden co-premise
Another error occurs when a crucial linking assumption remains invisible.
[For example:]ecampusontario.pressbooks.pubFor example, 1A-a is a premise, which is itself supported by a reason…
- Crime fell after the mayor took office.
- Therefore, the mayor’s policies reduced crime.
The hidden premise is that the policies, rather than other factors, caused the decline. Without that assumption, the evidence does not connect to the conclusion. Making the missing premise explicit often reveals where the argument is vulnerable. [Federation University]federation.edu.auFederation UniversityMapping an argumentA good argument map will make all co-premises explicit. Doing so will allow… In these complex… [YouTube]youtube.comYou TubeYou Tube
Treating repetition as additional support
Arguments sometimes restate essentially the same idea in different words:
- Experts support the proposal.
- Specialists support the proposal.
- Therefore, the proposal is sound.
If “experts” and “specialists” refer to the same group, the argument does not contain two independent reasons. It contains one reason repeated twice. Mapping helps expose this kind of duplication.
False Support Patterns and Why They Matter
False support patterns occur when the structure of an argument creates an illusion of stronger evidence than actually exists.
One version is support multiplication. A linked set of premises is incorrectly treated as several independent reasons. The argument appears more robust because it seems to survive the loss of any one premise. In reality, removing a single co-premise may collapse the entire inference. [Wikipedia]WikipediaArgument mapArgument map
Another version is evidential stacking. Several statements appear to provide cumulative support, but they all depend on the same underlying assumption. When that assumption fails, the entire structure weakens at once.
[For example:]ecampusontario.pressbooks.pubFor example, 1A-a is a premise, which is itself supported by a reason…
- The company’s profits rose.
- Its share price increased.
- Investors seem optimistic.
These may look like three independent reasons to believe the firm is healthy. Yet all three could depend on the same underlying factor, such as a temporary market trend. The apparent diversity of support may be misleading.
Argument mapping is valuable because it forces analysts to identify where support originates rather than simply counting reasons. [critical-thinking.com.au]critical-thinking.com.auwhat is argument mappingIt's a way to show which claims justify what and how.Read more…
Testing Combined Support
A practical way to identify linked premises is the premise-removal test.
Remove one premise at a time
Ask:
- If this premise disappeared, would the remaining premise still support the conclusion?
- Would the support become weaker but still exist?
- Or would the inference collapse completely?
If the inference collapses, the premises are probably linked. If meaningful support remains, they are probably independent. [philosophy.hku.hk]philosophy.hku.hkA10] Argument mappingThis merging of the links indicate that the two premises are co-premises which work together in a single argument t…
Look for a missing bridge
When a premise seems unrelated to the conclusion, ask what unstated claim would connect them.
Many apparently simple arguments rely on hidden assumptions. Identifying that hidden bridge often reveals a linked-premise structure rather than an independent one. [Reasoning for the Digital Age]reasoningforthedigitalage.comReasoning for the Digital AgeDependent/Linked PremisesDependent premises (sometimes called 'linked' premises) logically require each othe… [2arXiv]arxiv.orgSource details in endnotes.
Ask whether the reasons answer different questions
Independent reasons usually provide different routes to the conclusion. Linked premises often answer different parts of the same route.
[For example:]ecampusontario.pressbooks.pubFor example, 1A-a is a premise, which is itself supported by a reason…
- “She was at the meeting.”
- “The meeting approved the proposal.”
Together they support the claim that she witnessed the approval. Each premise contributes a different component of one inference rather than providing separate support.
What Linked Premises Reveal About Fallacies
Many informal fallacies become easier to diagnose once linked premises are identified correctly.
A weak argument may seem persuasive because readers unconsciously count each co-premise as a separate piece of evidence. The problem is not always a named fallacy such as hasty generalisation or false cause. Sometimes the deeper issue is structural: the argument possesses only one fragile line of support disguised as several.
Argument maps expose this by showing where premises merge, where assumptions are hidden, and whether support survives when individual claims are tested. When a supposedly strong case depends on a single linked chain, the failure of one premise can undermine the entire argument. Recognising that dependency is often the first step in finding the real weakness in the reasoning. [web-archive.southampton.ac.uk]web-archive.southampton.ac.uk13. If the argument map is done properly, then all co-premises of a reason are necessary for the…Read more… [Wikipedia]WikipediaArgument mapArgument map [Federation University]federation.edu.auFederation UniversityMapping an argumentA good argument map will make all co-premises explicit. Doing so will allow… In these complex…
Amazon book picks
Further Reading
Books and field guides related to Are These Reasons Independent or One Linked Argument?. Use these as the next step if you want deeper reading beyond the article.
Asking the Right Questions
Teaches evaluation of how reasons combine to support conclusions.
A Rulebook for Arguments
Excellent for understanding linked premises and support patterns.
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Endnotes
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Source: Wikipedia
Title: [Argument map]({{ ‘argument-map/’ | relative_url }})
Link: https://en.wikipedia.org/wiki/Argument_map -
Source: philosophy.hku.hk
Link: https://philosophy.hku.hk/think/arg/complex.php?m=1Source snippet
[A10] Argument mappingNote that the two premises are connected together before linking to the conclusion. This merging of the links indic...
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Source: jan.ucc.nau.edu
Link: https://jan.ucc.nau.edu/~ghr/phi332/class/mod_2/top_4/Source snippet
4: Independent and Linked PremisesIn contrast to independent premises, linked premises work together to reach a conclusion. Consider the...
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Source: web-archive.southampton.ac.uk
Link: https://web-archive.southampton.ac.uk/cogprints.org/3008/1/reasonpaper.pdfSource snippet
13. If the argument map is done properly, then all co-premises of a reason are necessary for the...Read more...
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Source: cliffsnotes.com
Title: □ Independent premises: Use separate arrows to maintain
Link: https://www.cliffsnotes.com/study-notes/33664324Source snippet
CliffsNotesMastering Argument Mapping: A Guide to Analyzing ComplexArgument Mapping Rules: ○ Mapping Rules: □ Co-premises: Join together...
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Source: youtube.com
Link: https://www.youtube.com/watch?v=kGgLlip_lvcSource snippet
Argument Mapping: Understanding and Making Arguments w...Nate Otey from ThinkerAnalytix visits The Stoa to discuss argument mappi...
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Source: arxiv.org
Link: https://arxiv.org/abs/2408.08648 -
Source: philosophy.hku.hk
Link: https://philosophy.hku.hk/think/arg/complex.phpSource snippet
[A10] Argument mappingThis merging of the links indicate that the two premises are co-premises which work together in a single argument t...
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Source: quizlet.com
Title: Week 6
Link: https://quizlet.com/ca/779286448/week-6-argument-mapping-flash-cards/Source snippet
Argument Mapping FlashcardsIn argument maps, we depict co-premises by linking the arrows joining them to the conclusion using a "Y" shape...
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Source: federation.edu.au
Link: https://www.federation.edu.au/students/study-skills/study-resources/hdr-thesis/write-your-thesis/mapping-an-argument/Source snippet
Federation UniversityMapping an argumentA good argument map will make all co-premises explicit. Doing so will allow... In these complex...
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Source: critical-thinking.com.au
Title: what is argument mapping
Link: https://critical-thinking.com.au/thoughts/what-is-argument-mapping/Source snippet
It's a way to show which claims justify what and how.Read more...
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Source: quizlet.com
Link: https://quizlet.com/ca/670649555/lesson-6-argument-mapping-and-multi-layer-arguments-flash-cards/Source snippet
Lesson 6: Argument Mapping and Multi-Layer ArgumentsArgument maps can indicate whether an argument has co-premises or independent premise...
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Source: reasons.io
Title: Independent and Codependent Premises
Link: https://reasons.io/learn/06Source snippet
ReasonsCodependent and independent premises can also be used together to form more complex arguments. Here, we can strength the inference...
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Source: youtube.com
Link: https://www.youtube.com/watch?v=b7QMD8J1BEESource snippet
Step 3.2: Independent PremisesComments · Step 3.3: Dependent premises · Step 1: Distinguishing Arguments From Other Forms o...
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Source: youtube.com
Title: Gemini said
Link: https://www.youtube.com/watch?v=NJxTGuIQFh0 -
Source: youtube.com
Title: You Tube
Link: https://www.youtube.com/watch -
Source: youtube.com
Title: You Tube
Link: https://www.youtube.com/watch?v=ol4uuxM8xSI -
Source: youtube.com
Title: You Tube
Link: https://www.youtube.com/watch?v=sTPjC-7EDkc -
Source: youtube.com
Title: You Tube
Link: https://www.youtube.com/watch?v=RKplZwqFwVk -
Source: reasoningforthedigitalage.com
Link: https://reasoningforthedigitalage.com/dependentlinked-premises/Source snippet
Reasoning for the Digital AgeDependent/Linked PremisesDependent premises (sometimes called 'linked' premises) logically require each othe...
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Source: reasoningforthedigitalage.com
Title: Put the argument into standard form and make an argument diagram.Read more
Link: https://reasoningforthedigitalage.com/premise-indicators-serial-and-convergent-premises-argument-diagrams/Source snippet
Premise Indicators, Serial and Convergent...Construct or find TWO arguments that use either convergent or serial premises or both...
Additional References
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Source: researchgate.net
Link: https://www.researchgate.net/publication/245489403_Argument_Mapping_with_ReasonAbleSource snippet
(PDF) Argument Mapping with Reason!AbleA series of classic arguments is a large part of our subject matter, and argumentation is our prim...
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Source: reasoninglab.com
Link: https://www.reasoninglab.com/steps/Source snippet
6 Critical Thinking StepsFor those who require higher levels of analysis, Rationale provides the analysis map format to show the relation...
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Source: jostwald.com
Link: https://www.jostwald.com/ArgumentMapping/ArgMap6-Models.pdfSource snippet
6 – Model Argument MapsA good argument has to be valid (i.e. the logical structure of the argument is such that if all the premises are t...
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Source: modeldiplomat.com
Link: https://modeldiplomat.com/learn/lessons/argument-mappingSource snippet
Argument Mapping — LessonAn argument map is a visual diagram that shows the structure of an argument: which statements are premises, whic...
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Source: reasoninglab.com
Link: https://www.reasoninglab.com/wp-content/uploads/2013/10/Argument-Maps-the-Rules.pdf -
Source: studocu.com
Link: https://www.studocu.com/en-ca/document/university-of-winnipeg/intro-to-philosophy/argument-map-notes/20895522 -
Source: reasoninglab.com
Title: Argument Mapping Start at the top and working down in levels
Link: https://www.reasoninglab.com/wp-content/uploads/2013/10/One-minute-mapper.pdfSource snippet
Argument MappingStart at the top and working down in levels - add evidence to support (reasons – green) or oppose (objections – red) any...
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Source: researchgate.net
Link: https://www.researchgate.net/figure/A-simple-argument-with-co-premises-leading-to-a-conclusion_fig2_5298009Source snippet
ional tool to assist learners at all levels of their education develop skills...
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Source: studocu.com
Title: 5. What reasons are given for the premises in the main argument?Read more
Link: https://www.studocu.com/en-au/document/monash-university/critical-reasoning/week-6-ats2946notes/102446564Source snippet
Week 6 ATS2946 Notes: Understanding Argument Maps &...Draw an argument map for the main argument (Are the MAIN premises linked or indepe...
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Source: ecampusontario.pressbooks.pub
Link: https://ecampusontario.pressbooks.pub/criticalthinking1234/chapter/introduction/Source snippet
For example, 1A-a is a premise, which is itself supported by a reason...
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