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Know Your Logical Fallacies 20 Jul 2008

Posted by Jessa in Religion, Science.
Tags: , ,

Today’s lesson: post hoc ergo propter hoc

Post hoc ergo propter hoc (translation: “after this, therefore because of this”), often shortened to just “post hoc“, is an attempt to apply a cause and effect relationship to two events that happen in temporal succession.  This fallacy is generally expressed as:

X happened, then Y happened.
Therefore, X caused Y (or Y was caused by X)

Here’s a example, straight from my inbox:

Death is certain but the Bible speaks about untimely death!
Make a personal reflection about this…..
Very interesting, read until the end…..

It is written in the Bible (Galatians 6:7):
‘Be not deceived; God is not mocked: for whatsoever a man sow,that shall he also reap.

Here are some men and women who mocked God :

John Lennon (Singer):
Some years before, during his interview with an American Magazine, he said: ‘Christianity will end, it will disappear. I do not have to argue about that. I am certain. Jesus was ok, but his subjects were too simple, today we are more famous than Him’ (1966).

Lennon, after saying that the Beatles were more famous than Jesus Christ, was shot six times.

Tancredo Neves (President of Brazil ):
During the Presidential campaign, he said if he got 500,000 votes from his party, not even God would remove him from Presidency.

Sure he got the votes, but he got sick a day before being made President, then he died.

Cazuza (Bi-sexual Brazilian composer, singer and poet):
During A show in Canecio ( Rio de Janeiro ),while smoking his cigarette, he puffed out some smoke into the air and said:’God, that’s for you.’

He died at the age of 32 of LUNG CANCER in a horrible manner.

The man who built the Titanic
After the construction of Titanic, a reporter asked him how safe the Titanic would be. With an ironic tone he said: ‘Not even God can sink it’

The result: I think you all know what happened to the Titanic

Marilyn Monroe (Actress)
She was visited by Billy Graham during a presentation of a show. He said the Spirit of God had sent him to preach to her. After hearing what the Preacher had to say, she said: ‘I don’t need your Jesus’.

A week later, she was found dead in her apartment

Bon Scott (Singer)
The ex-vocalist of the AC/DC. On one of his 1979 songs he sang: ‘Don’t stop me; I’m going down all the way, down the highway to hell’.

On the 19th of February 1980, Bon Scott was found dead, he had been choked by his own vomit.

Campinas (IN 2005)
In Campinas , Brazil a group of friends, drunk, went to pick up a friend….. The mother accompanied her to the car and was so worried about the drunkenness of her friends and she said to the daughter holding her hand, who was already seated in the car: ‘My Daughter, Go With God And May He Protect You.’ She responded: ‘Only If He (God) Travels In The Trunk, Cause Inside Here…..It’s Already Full ‘

Hours later, news came by that they had been involved in a fatal accident, everyone had died, the car could not be recognized what type of car it had been, but surprisingly, the trunk was intact. The police said there was no way the trunk could have remained intact. To their surprise, inside the trunk was a crate of eggs, none was broken

Christine Hewitt (Jamaican Journalist and entertainer)
said the Bible (Word of God) was the worst book ever written.

In June 2006 she was found burnt beyond recognition in her motor vehicle.

Many more important people have forgotten that there is no other name that was given so much authority as the name of Jesus.

Many have died, but only Jesus died and rose again, and he is still alive.


See the fallacy?  These people mocked God (X happened), then they died untimely deaths (Y happened).  Therefore, they died untimely deaths because they mocked God (Y was caused by X).

Although the fallacy is pretty easy to spot in this example, sometimes it’s more difficult to see.   A good first step to try to determine if you’ve encountered a post hoc argument is to turn the argument around to see if it holds true.  In this case, the reverse would be:

“You can prevent dying an untimely death by not mocking God.”

Clearly, this doesn’t make sense.  Plenty of people who have died untimely deaths did not mock God.  The connection between the two events has not been established, so it’s a post hoc argument.

It is important to note that not all links between earlier and later events fall into the post hoc fallacy category.  Many scientific hypotheses start out as post hoc ideas.  But the causal relationships outlined in a hypothesis are then supported (or disproven) by evidence from properly-conducted experiments.  If it hasn’t been confirmed by evidence, proceed with skepticism.