Hi folks, welcome to another edition of Logical Fallacies Bootcamp, where I explain a (formal or informal) logical fallacy and provide a few examples. Today’s offering: the Post Hoc Fallacy, aka False Cause Fallacy.
“Post Hoc” comes from the Latin phrase, “post hoc, ergo propter hoc” which translates to “after this, therefore because of this.” This fallacy assumes that because one event happened after another, that therefore the earlier event must be the cause of the later event.
In a cause-effect world, of course the cause occurs before the effect. But with this fallacy, there is no evidence provided to show the causal link between the two events.
Examples:
“Violent crime increased after President X’s inauguration, so President X must be the cause of the increase.”
Without explaining some kind of logical chain of evidence linking President X and the increase in violent crime, this argument is assuming a link that is not readily evident.
A real life example:
“Vaccines cause autism!”
Despite repeated studies thoroughly debunking this, it persists in the anti-vaccine world. The fact is that the markers that indicate autism often do not occur or are not noticed until after the age that children are vaccinated. Anti-vaxxers confuse this with vaccines causing autism, when in fact it’s simply a coincidental bit of timing.
Sports rituals are another example — a lot of sports figures have rituals they perform, or taboos that they avoid, before playing/performing. Wearing “lucky socks” or standing on one foot for thirty seconds, or not eating fish the night before, or something like that, because they remember doing that before performing really well (or poorly). So in their mind, it becomes a causal link: “We made it to the playoffs because I didn’t brush my teeth the night before we had a game.”
Obviously, if evidence is provided that shows a causal link, then no fallacy has been committed. The key here is that that link between events is lacking, and the more unlikely the pairing, the more important it is that sufficient evidence be provided.
Avoiding the Post Hoc Fallacy is relatively simple: provide evidence or logic sufficient to prove the link between two events. Pretty straightforward, and yet lack of this is the cause of this fallacy in the first place.
Until next time, folks!
Logical Fallacies Bootcamp:
The Strawman
The Slippery Slope
Begging the Question
Poisoning the Well
No True Scotsman!
Ad Hominem
False Dilemma
Non Sequitur
Red Herring
Gamblers Fallacy
Bandwagon Fallacy
Appeal to Fear
The Fallacy Fallacy
Appeal to Personal Incredulity
Appeal to Authority
Special Pleading
Texas Sharpshooter
Cognitive Bias Bootcamp:
Bystander Effect
Curse of Knowledge
Barnum Effect
Declinism
In-Group Bias
Hindsight Bias