EVIDENCE
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Definition????
Support for a claim that is discovered from
experience or outside authority (page 112)
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A “claim” is just an “assertion” UNTIL and
UNLESS it is supported by evidence
What qualifies as “evidence” (and is
accepted as valid) varies by the spheres
being appealed to
Toulmin
Claim –
statement advanced to gain the adherence of others
Grounds –
conditions, events, that provide foundation for your claim
Warrant – general statements to justify the grounds
Backing –
specific EVIDENCE, values, credibility etc
Qualifier – the force of the argument (your acceptable level of uncertainty)
Rebuttal -
answer to anticipated questions by opposition/decision makers
Types of Evidence
All
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evidence is “sphere dependent”
Examples
Statistics
Testimony
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Examples
Definition: an illustration which can be
generalized to the claim being made
Find examples relevant to the Sphere you are appealing to
Examples appeal to values
Hypothetical Examples???
Statistics
 Quantifiable
 Mean
data
, Median, Mode
 Statistical
Trends/Tendencies
 Credibility of Sources (global climate change)
Testimony
(someone other than the person making the argument)
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Testimony of FACT
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Testimony of OPINION
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(expert opinion –can be countered by other
“experts” – becomes an issue of credibility
Where to Look
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Internet Search (look for authoritative sources)
Government Documents
Statistical Abstract of the United States
Organizational Publications
Periodical Publications
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Time, Newsweek, US News – NYTimes – Wall
Street Journal etc.
TESTS OF EVIDENCE
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Credibility – source qualifications
Accuracy/Reliability
Originality of Observation
(avoid second-hand evidence)
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Recency
Bias (attitudes of the observer – do they have a hidden agenda)
Consistency or Contradiction with
established info/data
Statistics
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Source bias
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Statistical Accuracy (statistical exercise)
(NRA or Uniform Crime Reports of the DOJ?)
Simply put – do the numbers add up!!!!!
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Comparable units
(US and Canada? Or Iraq and Iran?)
Record/Save your Evidence
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Note cards
Data files on flash drives etc (so you are
not printing out lots of pages)
Reasoning with the Audience
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Cause and Effect
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Generalization
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A Parallel Case (events are similar)
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Comparative Advantage
(Inductive Reasoning – moving from
a specific to the general)
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Analogy
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Authority
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Appeal based on Dichotomy -
(fundamental sameness in different cases
one is “like” another)
– credibility and expertise
between only 2 choices
force a choice
Fallacies in Argument
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Hasty Generalization
(non representative sample
– too little info etc)
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Slippery Slope
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Red Herring
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Non Sequitur
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Circular Reasoning
(Irrelevant Argument – does not follow)
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Forcing a False Dichotomy
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Appeal to Ignorance
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Appeal to the People/popularity
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Appeal to Emotion
the contrary exists
(ad ignoratium) no proof to
(ad populum)
to peoples prejudices, “most people” or “it is commonly
known”
(such as emotionally charged
language – pro-murder etc)
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Appeal to Authority
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Appeal to Tradition
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Appeal to Humor
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Argumentum Ad Hominem –
not the argument (verbal aggression)
attack the person