A conclusion which relies on a premise which is based on the conclusion.
Example: “The Bible is the word of God – I know that because it says it in the Bible and it must be true because the Bible is the word of God.”
Denying the Antecedent
Assuming that a cause is based on the effect when there are multiple possible causes.
Example: “If you get a good degree, you’ll get a good job. If you don’t get a degree, you won’t get a good job.”
Ignoring a Common Cause
Claiming a link between 2 events, when there is a 3rd event which is likely to be the cause.
Example: “During the 60s there was a sexual revolution, because of that people are dying of AIDS.”
Cum Hoc Ergo Propter Hoc
Claiming that 2 events that occur together must have a cause-effect relationship and assuming that correlation = cause.
Example: “Smart people wear glasses, so wearing glasses must make you smarter.”
Affirming the Consequent
Assuming that there’s only one explanation for an observation you’ve made.
Example: “Marriage usually results in children, so that’s why marriage exists.”
Post Hoc Ergo Propter Hoc
The claim that because one event followed another, it was caused by it. Another cause-effect fallacy.
Example: “Since Obama became president, ISIS has become more powerful. Therefore, Obama has caused the rise of ISIS.”
Two Wrongs Make a Right
If someone is wronged, then another wrong will cancel it out
Example: “They killed 100 of our soldiers, so we need to kill 100 of their soldiers to make it right.”
Abstract: The fallacy of false cause and its forms as non causa pro causa and post hoc ergo propter hoc is disussed with examples.
I. False Cause: the fallacy committed when an argument mistakenly attempt to establish a causal connection. There are two basic interrelated kinds.
- Post hoc ergo propter hoc: (literally "after this, therefore because of this") the fallacy of arguing that one event was caused by another event merely because it occurred after that event.
- I.e., mere succession in time is not enough to establish causal connection. E.g., consider "Since hair always precedes the growth of teeth in babies, the growth of hair causes the growth of teeth."
- Consider also "Every severe recession follows a Republican Presidency; therefore Republicans are the cause of recessions." Accidental generalizations need not always be causal relations.
- Causal connections are difficult to establish; the nature of causality is an active area of inquiry in the philosophy of science.
- Non causa pro causa: (literally "no cause for a cause") in general, the fallacy of making a mistake about the ascription of some cause to an effect. This is the general category of "false cause."
II. The informal structure of the fallacy is usually similar to one of the following.
Event x is related to (or is followed by) event y.
Event x caused event y.
Events of kind x are followed by events of kind y.
Events of kind x cause events of kind y.
III. Examples of false cause:
"We hear that a writer has just filed a two million dollar lawsuit against the Coors beer company for pickling his brain. It seems that he had been consuming large quantities of Coors' 3.2 beer, containing only 3.2 percent alcohol and so supposedly non-intoxicating, at his local tavern. But, the suit contends, the stuff was insidiously marinating his mind; and as a result he has been unable to finish writing his second novel. The author may have a point. But we have to wonder whether the damage was caused by the beer, or by the current fad of product liability suits." Wall Street Journal (02.14.79).
There are two cases of false cause here, but the second, the Journal's, is tongue-in-cheek
"Napoleon became a great emperor because he was so short."
(If this were a causal inference, then all short people would become emperors.)
"Dear ABBY: If GOING BALD doesn't have any sighs of rash, or sores on her head, she should make a mixture of castor oil and sheep dung, and plaster it on her head every night. (Tell her to wear a shower cap so she won't mess up her pillow.) I started losing my hair after the birth of my child. My grandmother gave me this remedy and it worked. Index Journal (02.01.80).
"Defense attorney Ellis Rubin claims Ronald Zamora's constant exposure to TV crime shows such as re-runs of 'Kojak' and 'Police Woman' was responsible for 'diseasing his mind and impairing his behavior controls.' 'Without the influence of television ... there would not have been any crime,' Rubin argued." Index Journal (08.13.77).
"When the telephone was first introduced to Saudi Arabia, some contended it was an instrument of the devil. But others pointed out that, according to Moslem doctrine, the devil is incapable of reciting the Koran. When several verses of the Koran were recited and heard over the phone, skeptics were convinced that the instrument wasn't evil." Wall Street Journal (11.11.79).
"Especially bothersome to some parents whose children have chest pain, are reports in the media of sudden death in what appeared to be otherwise healthy athletes. There are many causes of chest pain in children. The most common cause is called idiopathic chest pain. Idiopathic means the cause is unknown. One can only call chest pain idiopathic after they have ruled out other causes." Randy Robinson, M.D. "Family Practice Notes," Index Journal (n.d.).
IV. Establishing causality in science is difficult. Usually if all A's are followed by B's then one suspect that A caused B. But even this generalization could be a coincidence. For the most part, causality is no longer used in science; correlation is sought instead.