James Stuart Mill

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James Stuart Mill

• CAUSE EFFECT
• RELATIONSHIP

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CAUSE EFFECT RELATIONSHIP

• System of Logic" Mill explains FOUR methods of
  experimental inquiry to find out the relationship
  between CAUSE EFFECT
• Cause is the invariable unconditional
  antecedent
• Effect is the consequent phenomena that
  invariably follows the cause

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CAUSE EFFECT RELATIONSHIP

• In the presence of Cause, Effect should occur
• In the absence of Cause, Effect should not occur
• A Cause Effect must be co-present , or
  co-absent
• Any change in one of them, must be reflected in
  the other

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CAUSE EFFECT RELATIONSHIP

• That is not the cause of a phenomenon, in the
  absence of which the phenomenon occurs
• That is not the cause of a phenomenon, in he
  presence of which the phenomenon fails to occur

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CAUSE EFFECT RELATIONSHIP

• That is not the cause of a phenomenon, which
  varies when the other is constant, or is constant
  when the other varies, or varies in no constant
  proportion
• That is not the cause of a phenomenon, which is
  known to be the cause of another phenomenon

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CAUSE EFFECT RELATIONSHIP

• The above principles are applied in the methods
  of inquiry explained y Mill.
• 1. Method of Agreement
• 2. Method of Difference
• 3. Method of concomitant variation
• 4. Method of Residual variation

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Method of Agreement

• Compare several positive instances of the same
  phenomena
• The circumstance (s) which agree commonly in all
  the instances can be the cause or effect of that
  phenomenon

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Method of Agreement

• Example
• P1 - a,b,c,d
• P2 - p,c,q,r
• P3 - m,n,o,c
• P4 x,y,c,z
• P C are co-present in all instances
• So C is the cause of P

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Method of Agreement

• 1st night Prolonged study, Heavy meal, Mentally
  alert, A cup of strong coffee
• 2nd night Prolonged study, light meal,mentally
  unrest, A cup of strong coffee
• 3rd night Very little study, Heavy meal,
  mentally quiet, A cup of strong coffee
• 4th night No study, light meal,mentally unrest,
  A cup of strong coffee

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Method of Agreement

• Disadvantages
• Plurality of Causes
• Difficulty in distinguishing Cause co-
  existence
• Antecedent Consequent may not be easily
  distinguished
• Possibility of non-observation of actual Cause
• Gives only the probable Cause

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Method of Difference

• Observation of Negative instances
• C and P may be co-present in many instances, but
  if present even once in the absence of P, it
  cannot be the Cause.
• If C and P are co-absent, the are causally
  related.

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Method of Difference

• Antecedents Consequents
• C,D,E P,Q,R
• D,E Q,R
• C P

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Method of Difference

• Example
• Coffee tastes Bitter
• On addition of Sugar, it becomes Sweet
• Sweetness Sugar are co-present, or co-absent
• Sugar is the cause of sweetness

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Method of Difference

• Advantages
• Experimental method effective in establishing
  Cause effect relationship
• More suited to testing Hypothesis
• Requires only 2 instances
• More scientific

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Method of Difference

• Disadvantage
• Valuable only if the circumstances are under our
  control completely

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Joint Method of Agreement Difference

• Double method of Agreement
• Agreement in the presence Comparing positive
  instances, look for common circumstances
• Agreement in the absence Using negative
  instances, we verify the Hypothesis

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Method of concomitant variation

• Any circumstance which is unaffected by the
  variation in the phenomena cannot be the cause of
  that phenomenon
• C1 P1
• C2 P2
• C3 P3
• C4 P4

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Method of concomitant variation

• Variation Directly proportionate
• Variation in the same direction Temperature
  Pulse rate
• Variation inversely proportionate
• Variation of the Two phenomena in opposite
  direction Insulin level? - Blood Glucose ?

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Method of concomitant variation

• Advantages
• Can quantify cause effect
• Calculate the amount of medicine needed to cure a
  disease
• Disadvantages
• Not applicable in Qualitative changes
• Applicable only if both phenomena are observable
  simultaneously

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Method of Residual variation

• Subtract fro any phenomena that part known by
  previous observations to be the effects of
  certain antecedents, and the residual phenomena
  is the effect of of the remaining antecedents

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Method of concomitant variation

• Antecedents Consequents
• C,D,E P,Q,R
• D Q
• E R
• C P