3. assessing arguments
TRANSCRIPT
‘Step-by-step’
Assessing Arguments:
AuthorshipWho says so?
AuthorityWho is he/she?
ProvenanceIs this a primary or a
secondary source?
Context
Evaluating
evidence’s
credibility &
relevance
When was it reported?
Is it focussed?
Is it representative?
Nature
Facts or opinions?
Accuracy
Is it accurate?
Are his/her views
shared?
STRUCTURE
CLARITY
EVIDENCE
LOGIC
EVALUATION
1
2
3
4
5
How to assess arguments?
5 Steps:
STRUCTUREStep 1
• Evidence
• Conclusion
Identify:
Two thousand years ago, the Earth was home to just 300 million humans, roughly the
population of the United States today. Two hundred years ago, 1 billion humans lived
on our planet Earth. The world population is now at over 6 billion and growing rapidly.
Thus, if current trends continue, we will add another 1 billion to the world population
every 13 or 14 years. (Extract from www.umac.org/ocp/CausesofGrowth/info.html)
CLARITYStep 2
Identify: • Any vagueness?
• Any confusion?
• Any assumption?
EVIDENCEStep 3
Assess: • Credibility
• Relevance
LOGICStep 4
Identify fallacies
FallacyMisleading or unsound argument
Mistakes in logic that are
independent of the
argument’s content.
(Flaws in the form of the
argument)
Formal fallacies Informal fallacies
Mistakes in logic that
arise from the content.
(Flaws in the content of the
argument)
Informal fallacies
(Only uses evidence that seem to confirm a particular position, while ignoring a significant portion of evidence
contradicting that position)
• Cherry picking
(assumes that correlation between two variables implies that one causes the other)
• Correlation proves causation
“Whenever I clean my car, it rains.”
(offers only 2 options when many more are possible)
“To lose weight, you either stop eating fries or have liposuction”
• False dilemma
• Ad Hominem
Informal fallacies
(attacks the opponent rather than the argument)
(uses emotion rather than evidence)
( questions the motives of the proposer to dismiss the proposer’s point )
(misrepresents the opponent’s argument)
“Prof Popper believes that an increase in rainfall will destroy crops but if there was no rainfall crops
would not grow in the first place”
“We must stop climate change or your children will drown under rising sea levels”
• Straw man
• Appeal to emotions
• Appeal to motive
“Of course Prof Popper says climate change is dangerous! She holds the Chair of
Innovation in Heuristic Climate Change Modelling”.
“What does Prof Popper know about global warming? She drives a Range Rover”.
STRUCTURE
CLARITY
EVIDENCE
LOGIC
1
2
3
4
5 Steps:
How to assess arguments?
EVALUATIONStep 5
Is the argument clear, with
valid evidence and logic ?
Strong
argument
Weak argument
Yes
No
STRUCTURE
CLARITY
EVIDENCE
LOGIC
EVALUATION
1
2
3
4
5
How to assess arguments?
5 Steps:
Global Challenges
Infectious diseasesPopulation
Climate changeObesity