Logical fallacy: X is bad, Y is worse, thus X is not bad

Question

I have heard this type of argument too many times: You are criticising X using well researched facts and arguments. Your interlocutor, states that Y is much worse with equally well researched facts and arguments. X and Y are linked in a general sense: two alternative medicines (homeopathy & chiropractics), two politicians (May & Corbyn), two historical figures (Hitler & Stalin). So far so good, it is a conversation.

Now, your interlocutor uses his arguments that Y is worse to suggest that X is in fact, good. This logical fallacy asserts that because Y is much worse than X, therefore X would be a good thing.

What is this logical fallacy called?

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Clearly in a binary choice, the lesser evil should win: X is bad, Y is worse therefore you should chose X. ⚠ This is not what this question is about.⚠ Please re-read the last sentence.

This logical fallacy asserts that because Y is much worse than X, therefore X would be a good thing. Not that it is a better choice, less-worst choice, the only choice but that it is a worthwhile choice on its own.

In addition, there might not be just two choices or one might not even be asked to make a choice: the fact that Y is worst makes X good regardless of X's merits.

Answer 1

This is (at least a subset of) the fallacy of relative privation.

From Wikipedia >> List of Fallacies >> Red herring fallacies

Fallacy of relative privation ("not as bad as") – dismissing an argument or complaint due to the existence of more important problems in the world, regardless of whether those problems bear relevance to the initial argument. For example, First World problem.

RationalWiki adds

[Use of this fallacy is] popular with people who know perfectly well they're doing something wrong; being fully aware that they're doing something wrong, they feel compelled to attempt to justify it and do so by pointing to other (usually worse) actions.

A hypernym (again, RationalWiki) (emphasis mine) appears to be

Moral equivalence is a form of equivocation and a fallacy of relevance often used in political debates. It seeks to draw comparisons between different, often unrelated things, to make a point that one is just as bad as the other or just as good as the other. It may be used to draw attention to an unrelated issue by comparing it to a well-known bad event, in an attempt to say one is as bad as the other. Or, it may be used in an attempt to claim one isn't as bad as the other by comparison. Drawing a moral equivalence in this way is a logical fallacy.

Answer 2

This seems like a false dilemma:

• major premise: "either X is good and Y is bad, or X is bad and Y is good".
• minor premise: "Y is bad".
• conclusion: "X is good".

Because the major premise is fallacious, the syllogism (though perfectly valid) is not sound.

In your examples it's elaborated slightly: the interlocutors both seem to agree, on some level, that both X and Y are bad; but because Y is putatively worse than X, Y gets assigned the role of "bad" and X gets assigned the role of "good" in order to conform to the major premise.

Answer 3

If this logical fallacy is used as a retaliative defense, it is called tu quoque ("you too"). You, who accuse me, do worse things than me; thus I am not bad. This doesn't cover all the instances, but it came to mind upon seeing Trump and Clinton in the question.

Answer 4

It's not an informal fallacy, it's a formal, logical one. It doesn't have a name, but perhaps should have a nickname because it is encountered so frequently lately. If you reduce it to form, you'll see it makes zero sense:

a is bad
b is double-bad
therefore,
 a is good

It's a failure of form (this argument can never be valid, no matter what the content), as its conclusion contradicts one of its premises.

Answer 5

From this problem we can form two propositions:

1. A is good           - we'll call this 'G'
2. B is worse than A   - call this 'W'

From these propositions we can form three hypotheses and a conclusion, based on the original problem:

Hypothesis 1:   ¬G
Hypothesis 2:   W
Hypothesis 3:   W→G
Conclusion:     G

This is a contradiction, as ¬P∧P can only ever equate to be false. Hypotheses 2 and 3 can be ignored - and logically, hypothesis 1 and the conclusion contradict.

"A logical contradiction is the conjunction of a statement S and its denial not-S. In logic, it is a fundamental law- the law of non contradiction- that a statement and its denial cannot both be true at the same time." - G. Randolph Mayes http://www.csus.edu/indiv/m/mayesgr/phl4/handouts/phl4contradiction.htm

Answer 6

I think it's to do with relativism.

If you only know X and Y, and know that Y is worse than X, then you have the situation described in the OP.

To know that X is bad, either you need to know about some "absolute" good (against which to compare X and find it bad), rather than mere "relative" good; or at least you need to know a third thing, Z, which is relatively good and compared to which X is bad.

In if you want to support your proposition that X is bad, in spite of your interlocutor's reminder that Y is worse, either you need to define what "absolute" good is or you need to explain what third choice you're comparing X with.

In your "homeopathy & chiropractics" example, you could argue:

• "My definition of 'absolute good' is a treatment proven via evidence-based medicine" (according to which absolute standard, both "homeopathy & chiropractics" fail)
• "My examples of 'relatively good' are e.g. vaccine and physical exercise" (compared with which, both "homeopathy & chiropractics" are relatively ineffective)