This method is somewhat similar to logical consistency. The main difference is that while logical consistency focuses on the inconsistency between claims or principles, consistent application is focused on criticizing an inconsistency in the application of a principle.
This method is generally employed as an attack method. This is to say that it is generally used to criticize as opposed to being used to support a position.
Concepts, Assumptions & Method
A principle is consistently applied when it is applied in the same way to similar beings in similar circumstances. Inconsistent application is a problem because it violates three commonly accepted moral assumptions: equality, impartiality and relevant difference.
Equality is the assumption that people are initially morally equal and hence must be treated as such. This requires that moral principles be applied consistently. Naturally, a person’s actions can affect the initially equality. For example, a person who commits horrible evil deeds would not be morally equal to someone who does predominantly good deeds.
Impartiality is the assumption that moral principles must not be applied with partiality. Inconsistent application would involve non-impartial application.
Relevant difference is a popular moral assumption. It is the view that different treatment must be justified by relevant differences. What counts as a relevant difference in particular cases can be a matter of great controversy. For example, while many people do not think that gender is a relevant difference in terms of how people should be treated other people think it is very important. This assumption requires that principles be applied consistently.
Consistent application, as a method of argumentation, has the following steps.
Step 1: Show that a principle/standard has been applied differently in situations that are not adequately different.
Step 2: Conclude that the principle has been applied inconsistently.
Step 3 (Optional): Require that the principle be applied consistently.
Applying this method often requires determining the principle the person/group is using. Unfortunately, people are not often clear in regards to what principle they are actually using. In general, people tend to just make moral assertions and leave it to others to guess what their principles might be. In some cases, it is likely that people are not even aware of the principles they are appealing to when making moral claims.
The following is an example of this method. Suppose that Barbara claims that male-only country clubs are immoral and should be opened to women. But then Barbara claims that women should be allowed to have women-only gyms so they can work out without being gawked at by men. If Barbara’s principle is that exclusion based on gender is immoral, then she is not applying the principle consistently. This is because it is applied one way to men, another way to women. Thus, her application is flawed and is thus subject to criticism on the grounds of this inconsistency.
Responding to a Charge of Inconsistent Application
There are four main ways of responding to a charge of inconsistent application. The first is to admit the inconsistency and stop applying the principle in an inconsistent manner. This obviously does not defend against the charge but can be an honest reply.
A second and actual defense is to dissolve the inconsistency by showing that the alleged inconsistency is merely apparent. One way to do this is by showing that there is a relevant difference in the situation. Returning to the gender equality example, the alleged inconsistency could be dissolved by arguing that country clubs are relevantly different from gyms or that men are relevantly different from women in this case. Successfully arguing for either of these would justify the difference in application and hence defeat the charge of inconsistency. This is because the application is only inconsistent if the situations are morally the same.
A third way to reply is to reject the attributed principle. Using the inequality example presented above, a person could claim that her actual principle justifies the difference in application.
Fore example, she might claim that her actual principle is that women should be treated equally except when it is to their advantage to be treated differently. Alternatively, she might claim that her actual principle is that people should not be discriminated against except in cases in which the presence of one gender would create undue discomfort to the other gender. Naturally enough, the “new” principle is still subject to evaluation. For example, the principle that allows women to be treated unequally when doing so is to their advantage seems to violate the standards of equality, impartiality and relevant difference. The other sample principle is less problematic and could be supported by an argument based on the fact that each gender has its own restrooms, locker rooms, etc.
A final, somewhat extreme, method of replying is to undercut the method by arguing against the grounding assumptions of this method-the principles of equality, impartiality, and relevant difference. To the degree that these assumptions are undercut, the method is weakened.