Method of Difference (PDF)

# METHOD OF DIFFERENCE Mill has defined the Method of Difference thus: “If an instance in which the phenomenon under investigation occurs, and an instance in which it does not occurs, have every circumstances in common save one, that one occurring only in the former; the circumstance in which alone...

# METHOD OF DIFFERENCE Mill has defined the Method of Difference thus: “If an instance in which the phenomenon under investigation occurs, and an instance in which it does not occurs, have every circumstances in common save one, that one occurring only in the former; the circumstance in which alone the two instances differ is the effect, or the cause, or an indispensable part of the cause, of the phenomenon.” From the above definition, it can be noted here that the principle of the Method of Difference is that whatever cannot be eliminated without interfering with the phenomenon under investigation must be causally connected with the latter. This means, if the cause is absent, the effect will also be absent or a circumstance in which it is present, the phenomena (effect) does not occur, cannot be the cause. ## Method of Difference assumes two forms. They are: - We add something to the antecedent, and the result is that something new happens in the consequents. - We may subtract something from the antecedents and something disappears from the consequents. Thus, it is the singleness of the difference that constitutes the ground of proof as the two instances differ only in one respect and this is called the Method of Difference. Method of Difference is essentially a method of experiment because only experiment can furnish the instances of the special kind required for this method. Thus this method can conclusively prove causation. ## Symbolic example: | A | X | - | B | Y | B | Y | A | X | |---|---|---|---|---|---|---|---|---| | C | Z | C | Z | ABC is | Caus | Effec | Caus | Effec | | Caus | Effec | Caus | Effec | | e | t | e | t | | e | t | e | t | followed by XYZ | BC is followed by YZ. Therefore A is the cause of X or X is the effect of A. The symbolical expression shows that only two instances are considered, and each instance is a group of antecedents which is symbolized by A, B and C and which is followed by a group of consequents which is represented by X, Y and Z in the first instance. Again a group of antecedent representing B and C which is followed by Y and Z in the second instance. Based on the principle of the method, the phenomenon under investigation occurs, that is, the phenomena X occurs in the presents of A in the first instance whereas the phenomena X is absent in the absence of phenomena A in the second instance and in the rest, it fails to occur. That means, ‘if the cause is absent, the effect will also be absent' or 'A circumstance in whose presence the phenomenon (effect) does not occur cannot be the cause.' Therefore A is causally connected with X. ## Critical estimate: The Method of Difference has the following uses or advantages: 1. The Method of Difference is pre-eminently a method of experiment and proves causal connection and has more scientific value. 2. The Method of Agreement supplies data to confirm the conclusions. 3. It requires only two instances, although these instances must be of a special kind. 4. Certainty of the conclusion arrived at by means of this method is dependable and reliable. The Method of Difference too has certain disadvantages: 1. The Method of Difference cannot be directly applied to reasoning from effect to cause. 2. Where the phenomena are complex, beyond our control, this method cannot be applied. 3. Like the Method of Agreement, this method is also not free from plurality of causes. 4. By means of this method, the cause cannot be sufficiently analyzed, in distinguishing a cause from a condition. 5. When this method is used for investigations in the social sciences, the difficulties are further multiplied. 6. Misapplication of this method leads to commit the fallacy of "post hoc ergo propter hoc" – after this; therefore, on account of this.