Post Hoc
Fallacy
(Faulty Casualty/Non-Sequitur)
Evan Payne
Definition
• Simply where one past
event is used to explain a
current one, though they
may be completely
unrelated
• Ex. I crashed my car into
a tree. The tree was a
cedar. So cedar trees
must cause car crashes.
• “Post hoc, ergo propter hoc,” meaning
“After this, therefore because of this.”
• Used to explain an event by saying a
previous event caused it
This graph shows the apparent correlation
between the number of Firefox downloads
and new WICCA members. WICCA is a
modern cult/religion of witchcraft. The
creators of this ad (as it is an ad, since its
promoting Internet Explorer seen in the
left) are trying to show that Firefox leads to
following WICCA. The “Keep the Faith” is
an appeal to Christians, designated by a
cross.
The Crucible
• Type: Post Hoc
• Character: Giles Corey
• Quote: “Last night—mark this—I tried and
tried and could not say my prayers. And
then she close her book and walks out of
the house, and suddenly—mark this—I
could pray again!” –Act 1, pg. 186
The Crucible
• Explanation: In the frenzy of witchcraft
accusations, Giles Corey states that he
believes his wife is guilty, saying that he
couldn’t pray when she had her books out.
Just because A happened (she read her
books) doesn’t mean that it caused B
(Giles couldn’t pray). Could also be seen
as since she stopped reading, he could
pray.
The Crucible
• Type: Post Hoc
• Character: Mrs. Putnam
• Quote: “I knew it! Goody Osburn were
mid-wife to me three times. I begged you
Thomas, did I not? I begged him not to call
Osburn because I feared her. My babies
always shriveled in her hands!” –Act 1, pg.
189
The Crucible
• Explanation: Mrs. Putnam is backing
Tituba’s accusation of Goody Osburn,
claiming that she was responsible for the
death of her babies. Even though she was
her mid-wife three times, that doesn’t
mean it caused the deaths of the babies.
The Crucible
• Type: Post Hoc
• Character: Danforth
• Quote: [Hale speaking] “There is a
prodigious fear of this court in the
country—”
[Danforth] “Then there is a prodigious guilt
in the country.” -Act 3, pg. 214
The Crucible
• Explanation: Danforth believes that the
fear of the court comes from guilt.
However, the fear is caused by the court’s
actions, not personal guilt. So fear does
not mean a presence of guilt, with guilt
also meaning witchcraft. So fear of the
court does not necessarily come from guilt
of witchcraft.
Modern Society
• Type: Post Hoc
• Speaker: Al Gore
• Quote: “During my service in the United
States Congress, I took the initiative in
creating the internet.”
Bluedorn, Hans. “Post Hoc Al-Gore Propter
Hoc.” fallacydetective. Fallacydetective.
20 Apr. 1999. Web. 15 Feb. 2012
Modern Society
• Explanation: Al Gore was attempting to
explain how he was different that his
opponent in this quote. However, he
claims that during his time in Congress, he
decided to make the internet. This implies
that the idea and inspiration for making the
internet was result of being in Congress,
which are not necessarily related.
Modern Society
• Many modern superstitions were born of
and based around a post hoc fallacy.
Many of the “bad luck” superstitions are
sustained because when people do these
unlucky actions, they blame any resulting
unfortunate event on the unlucky act.
Thus, the current action is not really a
result of a previous event.
Works Cited
• “Logical Fallacies.” Niyamaklogic.
Niyamaklogic. May 2009. Web. 14 Feb.
2012
• “Keep the Faith.” Jazzroc. Jazzroc. Nov.
2008. Web. 14 Feb. 2012
• “Post Hoc Examples.” Hub Image. Hub
Image. n.d. Web. 14 Feb. 2012