Logical Fallacies

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Logical Fallacies

Based on the list and definitions at http://www.don-lindsay-archive.org/skeptic/arguments.html

Definitions

What are some common or interesting logical fallacies?

Euphemism, e.g., replacing words with strong negative connotations with milder ones in Internet discussions

Notice that the definitions of some of the fallacies in this list are a little different than expected from use of the terms in everyday speech. Some of this reflects the fact that as names of fallacies, the terms are more technical than in everyday speech, but also realize that there isn’t some standard list and set of definitions of “the” fallacies anywhere, so while there’s a lot of agreement on the most important ones, each person’s list will differ from others in its details and exact definitions.

Examples

Some more or less “real world” examples (some more real than others).

From “The Big Bang Theory”:

The ad that preceded this video opened with a fallacy, namely the “appeal to the masses” one, when it tried to build interest in organizational culture resources by saying that 94% of respondents to some study thought organizational culture was important.

The “post hoc, ergo propter hoc” fallacy is assuming that because one thing happens before another, the first one caused the second.

From “The Simpsons”:

This is a false cause fallacy, or the colloquial phrase “correlation doesn’t imply causation,” i.e., just because 2 things happen together doesn’t mean that one of them causes the other.

A collection of fallacies from the global conversation about COVID (I don’t agree with exactly how these have been classified as fallacies, but that’s part of the point — fallacies “in the wild” don’t always fit the neat categories people create):

https://www.chop.edu/news/news-views-name-logical-fallacy-covid-19-edition

Some points from our discussion of these fallacies:

• Several of them pose a question instead of explicitly stating a position. This is a common rhetorical move for people who want to cast doubt on something, but don’t really have an argument to make against it.
• False cause fallacies (e.g., example 3) are potentially present in any argument that claims a causal connection between two things, e.g., “Geneseo is highly vaccinated, and has a low COVID rate, so vaccines must work.” This might indeed be evidence for vaccine effectiveness, or it might be just an interesting coincidence; to make a compelling argument around it you’d need to provide more examples of low infection rates in highly vaccinated populations, maybe summarize the scientific basis for expecting vaccines to prevent disease, etc.
• This Web site identifies example 4 as an appeal to ignorance fallacy, although it would be a better example of such if it included a conclusion, e.g., “I heard we don’t know about the long-term side effects of the COVID-19 vaccine, so it’s probably not safe yet.”

And In Fairness…

What do you think of this: “your argument is fallacious, therefore your conclusion must be wrong.”

This is also a fallacy, because a conclusion can be true independently of a bad argument for it. So avoid fallacious logic in your own writing, and realize that lots of people will either deliberately or accidentally try to convince you of things through fallacious reasoning, but also realize that identifying fallacies isn’t the end of the story in judging someone’s ideas.

Next

Peer editing of “Turing” essay drafts.

We’ll do this in class, since that seemed to work slightly better than Zoom last time.

Bring computers to class, and be prepared to share your draft with a partner.

(And remember to share it with me sometime before Friday’s class.)

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