Perfect Analogy Fallacy




Description:This fallacy occurs when an analogical argument is rejected in an unprincipled way, usually by setting the standards of similarity too high.  Analogical arguments are discussed in some detail under the Fallacious Analogy entry, but I will recap the essential information here to explain this fallacy.

An analogical argument is an argument in which one concludes that two things are alike in a certain respect because they are alike in other respects. Put somewhat formally, an analogical argument (fallacious or not) has this structure:


Analogical Argument (need not be fallacious)

Premise 1: X and Y have properties P,Q,R.

Premise 2: X has property Z.

Conclusion: Y has property Z.

X and Y are whatever is being compared. P, Q, R stand for properties that X and Y share. Z stands for the property that X is known to possess and Y is concluded to have based on the similarity between the two.

The logical strength of such an argument depends on three factors. The first is that the more properties the two things have in common, the stronger the argument. The second is that the more relevant the shared properties are, the stronger the argument. Finally, the more dissimilarities and the more relevant they are, the weaker the argument.

In the case of a Fallacious Analogy, the conclusion is accepted because the application of standards is too lax. The Perfect Analogy fallacy is somewhat of the reverse, the argument is rejected because the standards are set too high.

While there can be reasonable disagreement about how alike two things must be for an analogical argument to be strong, the Perfect Analogy fallacy occurs when the standards are set unreasonably high. In the most extreme version, the analogy would need to be perfect. That is, the two things being compared would need to be identical.

When this fallacy is committed in good faith, it occurs in ignorance. In such cases, the person is unwarranted in rejecting the analogy, but are unaware their standards of similarity are unreasonably high. In the case of bad faith, the use of the fallacy is intentional.

The fallacy usually takes the form of rejecting an analogical argument because of an alleged difference between X and Y. This reasoning is not inherently fallacious; showing that X and Y are too different to make a strong comparison would show that the analogical argument is weak. The fallacy occurs when the relevance and significance of the alleged difference are not adequately justified. In practice, a person using this fallacy will just assert there is a difference and reject the analogical argument. It has the following form:

Premise 1: Argument by analogy A concludes that Y has Z.

Premise 2: But D is a difference between X and Y.

Conclusion: Therefore, argument by analogy A is a weak (Fallacious) analogy.

The fallacy occurs when Premise 2 is not adequately supported, simply asserting there is a difference does not prove the analogical argument is weak. In some cases, the next step is to commit the Fallacy Fallacy by inferring that because a Fallacious Analogy has (allegedly) occurred, the conclusion of that argument is false:

Premise 1: An argument by analogy A concludes that Y has Z.

Premise 2: Argument by analogy A is a Fallacious analogy, as per the previous argument.

Conclusion: Therefore, Y does not have Z.

This is fallacious for the usual reason that the Fallacy Fallacy is fallacious, a fallacious argument can have a true conclusion. A person can also save time by committing both fallacies at once:

Premise 1: An argument by analogy A concludes that Y has Z.

Premise 2: D is a difference between X and Y.

Premise 3: Therefore, argument by analogy A is a Fallacious Analogy.

Conclusion: Y does not have Z.

Another version of this fallacy uses a tactic analogous to Moving the Goal Posts and consists of repeatedly rejecting analogical arguments until the target gives up. At that point, an Appeal to Silence might be used. Like the standard Moving the Goal Posts, this is an interactive fallacy used in a discussion. In more detail, here is how a fully developed Perfect Analogy fallacy would occur.

The first step is the unprincipled rejection of an analogical argument by claiming in some manner that it does not meet the standards of an analogical argument. As would be expected, someone committing this fallacy will usually not reference the standards of an argument by analogy. They will usually just say there is some difference and infer that this disproves the analogy. But this might be done in a way that seems reasonable, to try to create the illusion that the criticism is being made in good faith and thus set the stage for the bad faith arguments to follow.

If this criticism is addressed by revising the original argument or presenting a new one, then the response will be to reject this argument, asserting that it does not meet the standards. In practice, this usually just involves the assertion of a difference and the rejection of the analogy. The progression of the fallacy often reveals that the person is arguing in bad faith: the only analogy they will accept is a perfect one, effectively the comparison of the thing (Y) to itself. Anything that is different will be rejected because of that difference. But the person’s goal is to “prove” that Y does not have Z, so they can be seen as attempting a form of Begging the Question because they do so by assuming that Y does not have Z:

Premise 1: Only Y is the same as Y.

Premise 2: Y does not have Z.

Conclusion: Y does not have Z.

This process will repeat until one side gives up. If the target gives up, this is often met with an Appeal to Silence. If the target does not give up, the exchange will often end in an Ad Hominem attack or insult as the discussion is abandoned.

Defense: To avoid committing this fallacy when you are assessing an analogical argument be sure to apply the three standards fairly and back up your assessment with reasons. You might find that the argument is weak or even fallacious, but if your assessment is warranted, then you have not committed this fallacy.

If you suspect this fallacy is being committed by someone else, the main defense is to consider whether their criticism of the analogical argument is based on a reasonable application of the three standards. If they are simply rejecting the argument by merely asserting the analogy does not hold, then they are probably committing this fallacy. In such cases, you should not accept the rejection of the argument based solely on their fallacious argument. As always, it would be the Fallacy Fallacy to infer that they are wrong simply because they have committed a fallacy.

Before accusing a critic of committing this fallacy you should determine if this charge has a foundation. After all, good faith criticisms of an argument by analogy involve questioning the similarity between the two things and raising questions about relevant differences. If the critic brings up a difference without support for their claim that it is relevant and significant enough to undercut the analogy, then this would be grounds for suspicion. If they keep repeating the difference without supporting their claim or keep shifting to new, unsupported differences to reject the argument, then it would be reasonable to suspect they are engaged in this fallacy. Getting into a battle of endurance with someone engaged in this bad faith tactic is exhausting and usually pointless. To avoid getting dragged into this, a good defense is to point out that they seem to be using this fallacy and then directly asking what, if anything, they would be willing to accept as analogous. If they refuse or make a bad faith reply, the reasonable thing to do is end the discussion and expect an Appeal to Silence.

When trying to sort out good faith criticism from bad faith perfect analogy attacks there are two main things to look for. The first is, obviously enough, at least an attempt to argue that the claimed difference is relevant and significant. The second is to look for a willingness on the part of the critic to identify what similarities they would accept as relevant. If they refuse or require an unreasonable (or even impossible) level of similarity, then they are likely to be using this fallacy. It should also be noted that people can fall into this fallacy unwittingly: they do not have a conscious bad faith strategy; they simply believe that asserting a difference exists suffices to undercut the analogy. They would be reasoning in error, but not in bad faith. In such a case, they should be willing to correct their reasoning.


Example #1

Mike: “Okay, I do get that you are against mask mandates. I am somewhat infamous for my opposition to the tyranny of pants, so I am sympathetic to wanting to oppose the state trying to make us wear things.”

Randy: “Um, what do you mean about this pants thing? Do you go around naked or something?”

Mike: “Nah, I am always wearing something in public. It is kind of a joke, but also kind of serious. Whenever I go back to teaching in person, I say that I am back under the tyranny of the pants. That is, I must wear pants and a shirt in the classroom. I would prefer to just teach in a t-shirt and running shorts.”

Randy: “That would seem unprofessional.”

Mike: “Yeah. But I am a philosopher. But back to the masks. To be upfront about it, I don’t like wearing them, but I think the state has the legal right to compel us to wear them in public. Since I love analogies as much as I hate pants, do you think the state has the legal right to prevent me from running around naked in public?”

Randy: “Of course, no one wants to see that.”

Mike: “So, you should agree that that the state has a legal right to impose mask mandates. If it has the right to make us wear clothes, then it would seem to follow that it has the right to make us wear masks.”

Randy: “No! The pants thing is so people do not have to look at your junk. Especially jiggly runner junk.”

Mike: “You seem to have helped my argument here.”

Randy: “What?”

Mike: “Well, if the state can compel us to wear clothes just so people will not be offended or disgusted, then it should have the right to compel us so people will not get sick.”

Randy: “Um…those are different! I don’t want to see your junk, but I can tolerate your face. Mostly. The mask thing is about safety. Or so the libs say.”

Mike: “Well, what do you think about laws requiring people to use seat belts?”

Randy: “I don’t like wearing them, but yeah they seem legally okay.”

Mike: “Well, the mask mandate is like the seatbelt law; the state is using its legal right to require people to wear something to protect themselves and others.”

Randy: “Well, people don’t wear their seatbelts on their faces!”

Mike: “Well, except Jason.”

Randy: “True.”

Mike: “Okay, what about the laws requiring food workers to wear things like hairnets? Those are close to the face.”

Randy: “Close but not on the face. Also, the mask is a medical device. Hairnets are not medical.”

Mike: “But they serve the same purpose, namely protecting people.”

Randy: “Well hairnets protect people from…hair…in their food. So not the same.”

Mike: “So, is there anything like a mask?”

Randy: “Keep trying.”

Example #2

Rick: “I’m doing a paper on the ethics of police killbots.”

June: “The police have killbots?”

Rick: “Well, in 2016 Dallas police killed a suspect using a robot. So, yes.”

June: “Wow! Are they going to rebel against us and kill us all?”

Rick: “The Dallas police?”

June: “No, silly. The robots.”

Rick: “The robot they used was not autonomous, it was remote controlled. And that is the basis of my argument. I am going to argue that killing a person at a distance with a remote-controlled robot is morally the same as killing them with a gun. Both the gun and robot are machines for killing people at a distance, so morally the same.”

June: “I disagree. One is a robot, and the other is a gun. You need to redo the argument. If I can shoot it down like that, your professor is going to give you an F.”

Example #3

Joe: “Look, Jack, we regulate cars to protect people, so we should also regulate guns in the same way. Licenses, registration and so on.”

Jack: “Seat belts?”

Joe: “Yes…No. Well, sort of. Child safety locks. They are kind of gun seat belts.”

Jack: “Look, you can’t regulate guns like cars. We have a Constitutional right to keep and bear arms; we don’t have a right to keep and drive cars. So much for your plan, Joe.”

Example #4

Joe: “Look, Jack, we regulate cars to protect people, so we should also regulate abortion

Jack: “Look, you can’t regulate abortion like cars. We have a Constitutional right to abortion; we don’t have a right to keep and drive cars. So much for your plan, Joe.”

Originally appeared on A Philosopher’s Blog Read More