Irrelevant Conclusion
An irrelevant conclusion fails to answer the issue or receive the support claimed from its premises. Barbone uses the label broadly for conclusions that do not follow, including conclusions that happen to be true.
THE IDEA
33 Irrelevant Conclusion
Steven Barbone
You cannot convict my client of murder. We have proven that one of the arresting officers made prejudicial remarks, remarks scornful of my client. Look at the videotape, the audiotape, the man's own testimony. He is a full‐blown racist; you must not trust anything he says.
Loosely based on the O.J. Simpson case, from PhilosophicalSociety.com
Barbone uses irrelevant conclusion, or ignoratio elenchi (“ignorance of the proof”), broadly enough to call it the parent of other fallacies (see also Chapter 43 on the red herring fallacy). A useful distinction remains: premises can be relevant but insufficient to establish a conclusion, or they can address a different issue altogether. In either case, ask whether they provide the support being claimed. Consider these generalizations (assume for the sake of argument that they’re true):
- The Japanese eat little fat and have fewer heart attacks than Americans and the English.
- The French eat a lot of fat and have fewer heart attacks than Americans and the English.
- The Italians drink a lot of wine and have fewer heart attacks than Americans and the English.
- The Chinese drink little wine and have fewer heart attacks than Americans and the English.
What should we conclude? How about, therefore, eat and drink as you like; speaking English leads to heart attacks! We could for the sake of argument even agree that there is some odd causal connection between speaking English and having a heart attack (so the conclusion could be correct), but does this conclusion really follow from the premises? No, it does not. In fact, it’s not certain what follows from those premises. Here’s another example of an argument with an irrelevant conclusion:
- The United States had an active space program in the 1960s.
- The USSR had an active space program in the 1960s.
- Therefore, the United States was the first to land humans on the moon, in 1969.
In this example, all the premises are true. The conclusion is true too, but it does not necessarily follow from the premises. Except for some who believe that the moon landing is an elaborate hoax, we should believe that humans landed on the moon in 1969, but there being active space programs does not necessarily imply that there was a moon landing.
In this broad use of the term, there is no single form: the conclusion does not follow from the premises. We might imagine it like this:
Premise 1 + premise 2 + premise 3 […] premise infinity.
Conclusion A (where A has nothing to do with any numerical premise).
Avoiding this fallacy is easier said than done, for it requires one to be a critical thinker at all times. Any time someone tries to persuade you of something or you try to convince someone else of something, ask how the conclusion is related to the premises. Do they establish the conclusion, make it more probable, or merely provoke a reaction? Do the premises really support the conclusion or are the premises ambiguous or possibly misunderstood? Don’t just accept a conclusion because it’s labeled as such. Make sure it’s connected to the propositions that supposedly support it.
When to use it
In a debate about climate change, someone argues that because the Earth has had ice ages before, current global warming is natural—an irrelevant conclusion.
In a court argument, distinguishing a relevant challenge to a witness’s reliability from an unsupported leap to a verdict.
In a political discussion, a speaker claims that because the economy was good under a previous president, the current president's policies are bad—the conclusion does not follow from the premise.
In a scientific argument, anecdotal evidence is used to refute a statistical trend, ignoring that anecdotes do not disprove general patterns.
FROM THEORY TO EVERYDAY LIFE
In practice
O.J. Simpson Defense Argument
The source offers an argument loosely based on the Simpson case: an officer made racist remarks, therefore the client cannot be convicted. This is not a transcript of the defense. Evidence of prejudice can bear on a witness’s credibility, but does not by itself settle guilt or determine what the remaining evidence establishes.
Diet and Heart Attacks
From premises about the diets and heart attack rates of Japanese, French, Italian, and Chinese people, the argument concludes 'speaking English leads to heart attacks.' Even if the conclusion were true, it does not follow from the premises about diet.
Space Programs and Moon Landing
The premises state that the US and USSR had active space programs in the 1960s, but concluding that the US was the first to land on the moon in 1969 does not logically follow, even though both premises and conclusion are true.
A MOMENT TO REFLECT
Put it to work.
When you hear an argument, ask yourself: Does the conclusion logically follow from the premises?
Can you recall a situation where someone used an irrelevant conclusion to distract from the main issue?
How can you avoid committing the irrelevant conclusion fallacy in your own reasoning, especially when emotions are high?
CONTINUE THE CONVERSATION
Source texts
- Bad Arguments 100 of the Most Important Fallacies in Western Philosophy (Steven Barbone, Michael Bruce)