Confusing cause and effect is one of the most common logical fallacies. It's a principal component of most propaganda. It's also known as the correlation/causation error, Post Hoc Ergo Propter Hoc or the false cause fallacy.
This fallacy states:
If X happens and Y occurs, you can conclude that X is the cause of Y.
My knee aches just before it rains, therefore the ache in my knee is the cause of the rain. It is consistent, repeatable, and accurate therefore it must be true.
Causal fallacies occur because of scientific ignorance (although in many cases, the fallacy is intentionally misleading). The assumption is that two correlated phenomena have a causal relationship. This fallacy occurs when we assume that because two things have either a positive relationship (the more it rains, the more your knee aches) or a negative relationship (The more you watch tv, the less you exercise) that this means that one thing is the CAUSE of the other. This is not necessarily true, for while correlation is a necessary condition for causality, it is not a sufficient reason for a causality.
Here are some more examples:Republican presidential candidate Rudy Giuliani prominently featured one such myth in his speech Oct. 20 to a group of social conservatives. The former New York City mayor stated that "we increased adoption by 133% over the eight years before I came into office. And we found that abortions went down by 18% during that period of time. I believe we can do that in the United States."
Rudy Giuliani is veritable fountain of causal logical fallacies. Here's another one:
Another popularly known fallacy, this is actually an offshoot of the false cause fallacy. It occurs when an arguer claims one event must lead to a successive chain of less desirable consequences -without offering any other proof.
Example: "If we vote for Clinton, a known pot smoker, soon the whole Whitehouse will be filled with drug addicts.""Because if we make the wrong choice, then the danger is that we'll get hit again, that we'll be hit in a way that will be devastating from the standpoint of the United States, and that we'll fall back into the pre-9/11 mind set if you will, that in fact these terrorist attacks are just criminal acts, and that we're not really at war. I think that would be a terrible mistake for us."
Last updated by Nelson Feb 12, 2009.