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Flow Chart for Analyzing Arguments by Analogy

Contributed by Michael Connelly, Longview Community College.

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Some empirical premises are supported by Analogies. The arguments which support these premises must be analyzed in a particular manner. The general form of an argument by analogy will be:

  1. Some state of affairs A is like a state of affairs B in that they both share

    2. properties w,x and y.
  2. The state of affairs A has the additional property z
  3. Thus, the state of affairs B has the additional property z.
In analyzing such an argument, we can either question the premises (1&2) or question the conclusion (3). In calling into question the first premise, we will need to find either:
  1. a relevant property of A which is not shared by B which will defeat the conclusion or,
  2. a relevant dis-similarity between A and B which will defeat the conclusion.
In calling into question the second premise, we will need to show that either:
  1. the state of affairs described by A does not have the additional property, or
  2. the additional property is not relevant to the similarity being claimed.
In calling into question the conclusion, we only need to show that the similarity being claimed does not necessarily entail the conclusion. The easiest way to do this is to find a counter-example to the conclusion (another state of affairs which shared all of the similarities of A and B, but which did not have the additional property.

The Flow chart for Analyzing Analogies:


What we are looking for here is an expression of how the two instances that are being compared are similar.

 
 
 


Exactly which properties are being considered the same? Remember here that we are dealing with situation in which there are likely to be several dis-similarities. These can be considered only if they are relevant to the comparison being made.
 
 
 


 
 


 


 


 
 


Is there a similarity between the two cases which would defeat the inference made to the conclusion? If so, then the premise is probably false.
 
 
 


Is there a relevant way in which the two cases are dis-similar? If so, the conclusion of the argument, and thus the premise is probably false.
 
 
 


If not, the reject the conclusion - the premise is probably false.
 
 
 


 
 
 



 
 
 


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Critical Thinking Across the Curriculum Project
Longview Community College , Lee's Summit, Missouri - U.S.A.
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Inquiries to: michael.connelly@kcmetro.edu
Last modified: 03/02/04