In writing up your research you will inevitably need to construct arguments. Simply put, an argument is a claim supported by reasons that are presented with the aim of convincing the reader to accept the claim as being true or at least plausible. In the absence of those reasons, a claim remains an unsubstantiated assertion. While you may “get away” with a few such assertions, your examiner will expect any claims to be presented as part of an argument, the strength of which will depend on the strength of the reasons you offer in support of the claim. For some arguments the reasons for accepting the claim may be empirical evidence that the claim is true. For others, one may rely on the authority of certain texts. In this article, we will briefly introduce the use of analogy as a reason for accepting a claim.
An argument by analogy relies on the use of an alternative claim that has already received general or authoritative acceptance. The force of the argument is that the new claim is sufficiently similar to the established claim that is reasonable to accept the new claim based on the acceptance of the established claim. The form of the argument is: If claim X is accepted, then, since it is sufficiently similar to claim X, claim Y should also be accepted. Key to understanding how to use, or assess, such an argument, is the recognition that, while X and Y are different claims, the common characteristics shared by X and Y means that, if one claim is accepted, then the other claim should also be accepted.
Argument by analogy is particularly useful where there is no direct evidence to support the new claim, or where there is an inconsistency in the treatment of two similar situations. As a simple example consider gender pay inequality. The claim that women should be paid the same as men for doing the same job is essentially an argument by analogy. The essence of the argument is that, while women are biologically different to men, the difference is irrelevant to the issue of fair pay. In the context of employment, the relevant characteristic is the person’s ability to do the job and not whether the employee is male or female. Similarly, the argument for animal rights is an argument by analogy that highlights the relevant similarities between animals and humans while explaining that the differences are not relevant to the particular issue.