Tuesday, November 13, 2007

Logical Fallacies Part 2

6. Confusing association with causation
This is similar to the post-hoc fallacy in that it assumes cause and effect for two variables simply because they are correlated, although the relationship here is not strictly that of one variable following the other in time. This fallacy is often used to give a statistical correlation a causal interpretation. For example, during the 1990's both religious attendance and illegal drug use have been on the rise. It would be a fallacy to conclude that therefore, religious attendance causes illegal drug use. It is also possible that drug use leads to an increase in religious attendance, or that both drug use and religious attendance are increased by a third variable, such as an increase in societal unrest. It is also possible that both variables are independent of one another, and it is mere coincidence that they are both increasing at the same time. A corollary to this is the invocation of this logical fallacy to argue that an association does not represent causation, rather it is more accurate to say that correlation does not necessarily mean causation, but it can. Also, multiple independent correlations can point reliably to a causation, and is a reasonable line of argument.

7. Confusing currently unexplained with unexplainable
Because we do not currently have an adequate explanation for a phenomenon does not mean that it is forever unexplainable, or that it therefore defies the laws of nature or requires a paranormal explanation. An example of this is the "God of the Gapsâ" strategy of creationists that whatever we cannot currently explain is unexplainable and was therefore an act of god.

8. False Continuum
The idea that because there is no definitive demarcation line between two extremes, that the distinction between the extremes is not real or meaningful: There is a fuzzy line between cults and religion, therefore they are really the same thing.

9. False Dichotomy
Arbitrarily reducing a set of many possibilities to only two. For example, evolution is not possible, therefore we must have been created (assumes these are the only two possibilities). This fallacy can also be used to oversimplify a continuum of variation to two black and white choices. For example, science and pseudoscience are not two discrete entities, but rather the methods and claims of all those who attempt to explain reality fall along a continuum from one extreme to the other.

10. Inconsistency
Applying criteria or rules to one belief, claim, argument, or position but not to others. For example, some consumer advocates argue that we need stronger regulation of prescription drugs to ensure their safety and effectiveness, but at the same time argue that medicinal herbs should be sold with no regulation for either safety or effectiveness.

No comments: