Do I believe it? The three S’s: a guide to evaluating knowledge claims

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  How to evaluate claims:
  
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    Look for independent confirmation.
    
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    Include input from knowledgeable proponents from all points of view.
    
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    Don’t automatically trust the word of authorities.
    
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    Develop alternative hypotheses.
    
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    Be willing to give up your hypothesis.
    
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    Quantify or measure if possible.
    
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    Consider each the elements of the argument logically (in sequence). Do all the parts make sense?
    
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    Consider the possible motivation of the claim’s author.
    
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    Occam’s Razor. When faced with two hypotheses that explain the data equally well – choose the simpler.
    
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    Ask if the hypothesis can be falsified. Can a test be conducted to disprove the hypothesis?
    

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  Some other tips for considering evidence:
  
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    There is good reason to doubt a proposition if it conflicts with other propositions we have good reason to believe.
    
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    The more background information a proposition conflicts with, the more reason there is to doubt it.
    
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    When there is a good reason to doubt a proposition, we should proportion our belief to the evidence.
    
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    There is a good reason to doubt a proposition if it conflicts with expert opinion.
    
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    Just because someone is an expert in one field, it doesn’t mean that he or she is an expert in another.
    
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    Just because a large number of people believe something, it doesn’t mean that it is true.
    
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    If we have no reason to doubt what’s disclosed to us through perception, introspection, memory or reason, then we’re justified in believing it.
    
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    When evaluating a claim, look for the disconfirming as well as confirming evidence.
    
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    When evaluating a claim, look at all the relevant evidence, not just the psychologically available evidence.
    

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  Ad hominem – an argument which attacks the person, not the argument.
  
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  Argument from authority – blind trust because of the person’s position or status.
  
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  Argument from adverse consequences – you better believe this or else…
  
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  Argument ad ignorantium (Appeal to ignorance) – the claim that since the argument cannot be proved false, then it must be true.
  
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  Special pleading – the attempt to rescue a proposition in deep rhetorical trouble.
  
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  Begging the question – assuming the answer as part of the argument.
  
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  Observational selection – the enumeration of favorable circumstances (counting the hits, ignoring the misses).
  
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  Statistics of small numbers - 4 out of 5 dentists is a very small representative sample if only 5 dentists are surveyed.
  
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  Misunderstanding / misapplying statistics – “proven to be 20% more effective…” How was “effectiveness measured?”
  
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  Inconsistency – applying reasoning and evidence inconsistently to the proposition.
  
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  Non-sequitor – arguments which don’t follow and not logically related to each other..
  
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  Post hoc, ergo propter hoc – “it happened after, so it was caused by”
  
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  Meaningless questions – misapplication of words, language or ideas.
  
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  Excluded middle – false dichotomy – not including intermediate possibilities.
  
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  Short term vs. long term – one at the expense of the other.
  
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  Slippery slope – once you start, there is no stopping…
  
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  Confusion of correlation and causation – mis applying a cause and effect relationship.
  
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  Straw man – simplifying (caricaturizing) a position to make it easier to attack.
  
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  Suppressed evidence and half truths – inaccurate or missing details.
  
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  Weasel words – reinvention of words for political (or other) purposes.
  

Paul, R. and Elder, L. (2008) The Miniature Guide To Critical Thinking