Causal Reasoning

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Causal Reasoning
GXEX1406 Thinking and Communication Skills
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What isCausal Reasoning?
If you walk on a banana skin you will slip !!!
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What is Causal Reasoning?

•  Causal reasoning is a statement about cause and
  effect.
• It is human nature to seek a cause and effect for
  any circumstances/events/occurrences.
• CR attempts to show a definite relationship
  between things i.e. one event necessarily causes
  another. It is a form of inductive reasoning in
  which an event(s) is the result of another
  event(s).
•              

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Definition

• One can observe that B follows A, but not that B
  is caused by A.
• A cause must precede its effect.
• Example Studying hard (antecedent) leads to good
  grades (consequent)
• Causal relationships are inferred, not directly
  observed.

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Examples of Causal Reasoning

• Drinking and driving causes traffic accidents.
• A woman with blue eyes will have daughters with
  blue eyes.
• Violence on TV and in movies causes people to
  like violence

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How Does CR Work ?

• We found that that such an object is followed by
  such an effect
• We foresee other similar objects, will be be
  followed by similar effects
• Example
• The times I touched a hot iron with my bare
  hands, I was badly burned. ______________________
  ____________
• In the future, touching a hot iron will most
  likely burn my finger.

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Reasoning Pattern (Mills Method Of Reasoning)

•  There is a set of five careful methods to
  analyze and interpret our observations for the
  purpose of drawing conclusions about the causal
  relationships.
• These are Mills Method Of Reasoning
•  In this course we will only consider two of the
  methods.

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Mills Method Of Reasoning

• Method of Agreement
• Method of Difference

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Scenario 1

• In order to illustrate these two methods we
  consider the following scenario.
• Suppose that on an otherwise uneventful
  afternoon, the Doctor at the Klinik Kesihatan
  Mahasiswa becomes aware that an unusual number of
  students from FSKTM are suffering from severe
  indigestion.
• Dr. Adam naturally suspects that this symptom
  results from something the students ate for
  lunch, and he would like to find out for sure.
• (cont)

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Scenario 1

• The Doctor wants to find evidence that will
  support a conclusion that "Eating ?xxxx? causes
  indigestion."
• Mill's Methods can help.
• (cont)

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Mills Method of Agreement

• E.g.. Suppose that four students from FSKTM come
  to see Dr. Adam with indigestion, and he
  questions each about what they had for lunch.
• Dr. Adam Can you tell me what you had for lunch
  ?
• (cont)

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Mills Method of Agreement

• First Student (Aziz) I had pizza, roti canai,
  sugar cane, and an ice cream
• Second Student (Aisha) I had a burger and chips,
  roti canai, and iced lemon tea
• Third Student (Mary) I ate pizza and roti canai
  and drank iced lemon tea
• Fourth Student(Lim) I ate only chips, roti
  canai, and papaya.
• (cont)

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Mills Method of Agreement

• Dr. Adam, concludes
• "Eating roti canai caused the indigestion."
• (cont)

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Mills Method of Agreement

• Question Is eating roti canai the only relevant
  common factor preceding the indigestion?
• Only if it is can the argument be considered
  reliable.
• Question Could the indigestion be the result of
  independent causes? (I.e. Maybe there was a viral
  infection)
• The argument is reliable only if this possibility
  has been eliminated.

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Mills First Method (Method of Agreement)

• Generally,
• X is the common thread.
• X caused Y because X is the only relevant common
  factor in more than one occurrence of Y.

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Mills Method of Agreement

• Question Is X the only relevant common factor
  preceding the occurrences of Y?
• Only if it is can the argument be considered
  reliable.
• Question Did the occurrences of Y result from
  independent causes?
• The argument is reliable only if this possibility
  has been eliminated.

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Mill's Method of Difference

• On the other hand, suppose that only two students
  arrive at the Klinik.
• The two are roommates who ate together, but one
  became ill while the other did not.
• The first had eaten a burger, chips, roti canai,
  papaya and drank iced lemon tea,
• The other had eaten a burger, chips, papaya, and
  drank iced lemon tea.
• Again, Dr. Adam concludes that the roti canai is
  what made the first roommate ill.
• (cont)

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Mill's Method of Difference

• This reasoning applies comparison of a case in
  which the effect occurred and another case in
  which the effect did not occur revealed that only
  one prior circumstance was present in the first
  case but not in the second.
• In such situations, we commonly suppose that,
  other things being equal, different effects are
  likely to arise from different causes, and since
  only the student who had eaten roti canai became
  ill, it was probably the cause.
• (cont)

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Mill's Method of Difference

• Roti Canai is the difference.
• Roti Canai caused indigestion because roti canai
  is the only relevant difference between this
  situation, where indigestion occurred, and
  situations where indigestion did not occur.

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Mill's Method of Difference

• Question Is eating roti canai the only relevant
  common factor preceding the indigestion?
• Only if it is can the argument be considered
  reliable.
• Could the indigestion be the result of
  independent causes? (Again, the viral infection)
• The argument is reliable only if this possibility
  has been eliminated.

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Mills 2nd Method(Method of Difference)

• Generally,
• X is the difference.
• X caused Y because X is the only relevant
  difference between this situation, where Y
  occurred, and situations where Y did not occur.

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Mills 2nd Method

• Question Is X the only relevant common factor
  preceding the occurrences of Y? (Only if it is
  can the argument be considered reliable.) Did the
  occurrences of Y result from independent causes?
  (The argument is reliable only if this
  possibility has been eliminated.)

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Fallacies of Causality

• Questionable Cause aka Ignoring a Common Cause
• Assuming a Common Cause
• Misidentification of the Cause
• Slippery Slope
• post hoc ergo propter hoc

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Fallacies of Causality Questionable Cause

• This fallacy occurs when someone presents a
  causal relationship for which no real evidence
  exists.
• AKA Ignoring a Common Cause
• This fallacy has the following general structure
• X and Y are associated on a regular basis.
• (but no third, common cause is looked for).
• Therefore X is the cause of Y.
• (cont)

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Fallacies of Causality Questionable Cause

• The general idea behind this fallacy is that it
  is an error in reasoning to conclude that one
  thing causes another simply because the two are
  associated on a regular basis.
• More formally, this fallacy is committed when it
  is concluded that X is the cause of Y simply
  because they are associated on a regular basis.
• The error being made is that a causal conclusion
  is being drawn from inadequate evidence.
• Further, the causal conclusion is drawn without
  considering the possibility that a third factor
  might be the cause of both X and Y.
• (cont)

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Examples of Questionable Cause

• Example 1
• Ali gets a chain email that threatens him with
  dire consequences if he breaks the chain.
• He laughs at it and throws it in the rubbish bin.
  
• On his way to work he slips and breaks his leg.
• When he gets back from the hospital he sends out
  200 copies of the chain letter, hoping to avoid
  further accidents.
• (cont)

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Examples of Questionable Cause

• Example 2
• A thunderstorm wakes Tan up in the middle of the
  night.
• He goes downstairs to get some milk to help him
  get back to sleep.
• On the way to the refrigerator, he notices that
  the barometer has fallen a great deal.
• Tan concludes that the storm caused the barometer
  to fall.
• In the morning he tells his wife about his
  conclusion.
• She tells him that it was a drop in atmospheric
  pressure that caused the barometer to drop and
  the storm.
• (cont)

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Fallacies of CausalityAssuming a Common Cause

• This is the reverse of Ignoring a Common Cause
  (Questionable Cause)
• It consists of automatically assuming that two
  conjoined events must have had the same
  underlying cause.
• This fallacy occurs by claiming a link between X
  and Y when none exists.
• The moral is, "Don't unthinkingly assume that two
  conjoined occurrences have a common cause.
• But don't unthinkingly assume that they do not,
  either".
• (cont)

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Examples of Assuming a Common Cause

• "Both physicians ended up with cancer.
• There must be something about treating sickness
  that makes you get cancer.

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Fallacies of CausalityMisidentification of the
Cause

• In causal situations, we are not always certain
  about what is causing what.
• i.e. what is the cause and what is the effect.
• E.g.. "Headaches and tension"    
• "Failure is school and personal problems
• (cont)

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Fallacies of Causality Slippery Slope

• One undesirable action will lead to a worse
  action, which will lead to a worse one still, all
  the way down the 'slippery slope' to some
  terrible disaster at the bottom.
• Although this progression my indeed happen, there
  is certainly no causal guarantee that it will.
• (cont)

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Examples of Slippery Slope

• If we let this lady check 11 items through the 6
  item express checkout, you'll next be letting
  people walk out the store without paying, then
  speeding, murder and mayhem will be allowed, the
  country will go to

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Fallacies of Causality post hoc ergo propter
hoc

• Causality plays such a dominant role in our
  lives, and many a time mistakes or faulty
  reasoning occur.
• post hoc fallacy
• The post hoc ergo propter hoc (after this
  therefore because of this) fallacy is based upon
  the mistaken notion that simply because one thing
  happens after another, the first event was a
  cause of the second event.
• Post hoc reasoning is the basis for many
  superstitions and erroneous beliefs.
• (cont)

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Examples of post hoc ergo propter hoc

• You have a cold, so you drink fluids and two
  weeks later your cold goes away.
• You have a headache so you stand on your head and
  six hours later your headache goes away.
• You put acne medication on a pimple and three
  weeks later the pimple goes away.

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Testing Causal Relationships

• Is the cause necessary to produce the effect?
• E.g. Is it necessary to smoke to be cool?
• Is the cause sufficient to produce the effect?
• E.g. Is wearing trendy clothes sufficient to be
  cool?
• E.g. Is looking tanned or muscular synonymous
  with being physically fit?
• Are there alternative causal explanations
• Are there cumulative (additional, contributory)
  causes?
• Are there countervailing causes?