Difference between revisions of "Non sequitur"

Revision as of 19:37, May 15, 2007

Template:Fallacy Non sequitur (Latin, "It does not follow") is a logical fallacy that involves arguing from a premise to a conclusion with insufficient or no connection between the two.^[1]

Definitions

Classically, the term non sequitur applies to:

1. A conclusion that does not follow from the premises or evidence.^[2]
2. A statement that does not necessarily follow from preceding statements.^[2]

Some authorities use the term non sequitur to refer generally to any fallacy involving the introduction of irrelevant considerations.^[3] This, then, would include ad hominem and special pleading.

Example

The most common example of non sequitur is any attempt to infer causation from correlation alone. An argument of causality--that is, that X caused Y--is always subject to weakening if one can show that:

1. Y could have occurred with or without X.
2. Another event, Z, actually caused Y.
3. Y caused X rather than X causing Y.

The usual way to weaken a non sequitur is simply to show that two facts, that might happen to correlate, are in fact not mutually relevant. Of course, showing that the chain of implication is reversed--meaning that the first named fact actually follows from the second, rather than the second from the first--will cast even more serious doubt on the argument.

References

1. ↑ Glenn Whitman, Non sequitur, Glen Whitman's Debate Page, August 30, 2005. Retrieved April 9, 2007.
2. ↑ ^{2.0 2.1} Definition of non sequitur in The American Heritage® Dictionary of the English Language, 4th. ed., Houghton Mifflin Company, 2006. Retrieved April 9, 2007.
3. ↑ Paul Raveling, Non sequitur logical fallacies at SierraFoot.org. Retrieved April 9, 2007.

See Also

• Logical fallacy