Argument from Analogy

Similarities between objects, people and places pervade our thinking and influence our interaction with the environment. Many of these similarities serve no logical purpose but have a descriptive or explanatory function in our cognitive affairs. However, for the substantial number of analogies which are used in argument, their logical and other attributes have long been a source of fascination for investigators in a range of disciplines. It is argued in this chapter that cognitive agents use the argument from analogy as a facilitative heuristic to guide their judgements about public health problems when evidence or knowledge is not available in a particular context. To this extent, the argument is one type of adaptation of our rational procedures to the problem of uncertainty in the cognitive domain. Several examples of the use of this argument in a public health context are examined. The dialectical and epistemic features of this argument are addressed within a discussion of the use of analogical argument in systematic and heuristic reasoning. The results of a study of public health reasoning reveal that members of the public are adept at identifying the conditions under which the use of analogical argument is more or less rationally warranted.