Negative proof

:"This article is about a logical fallacy. The term "negative proof" can also refer to a proof of impossibility."Negative proof, the fallacy of appealing to lack of proof of the negative, is a logical fallacy of the following form:

: "X is true because there is no proof that X is false."

It is asserted that a proposition is true, only because it has not been proven false. The negative proof fallacy often occurs in the debate of the existence of supernatural phenomena, in the following form:

: "A supernatural force "must" exist, because there is no proof that it does "not" exist".

However, the fallacy can also occur when the predicate of a subject is denied:

: "A supernatural force "must not" exist, because there is no proof that it "does" exist."

: "Scientists "don't know" for sure what natural forces caused the first single-cell life, so it "must" be intelligent design."

Appropriate uses of negative evidence

In some cases a reversed burden of proof may be appropriate. This occurs when there are two competing explanations, and neither can be confirmed by observation. For example: when an empirical relationship has been observed, but the underlying mechanism is unknown, it may be reasonable to infer from the lack of conflicting evidence that the observed relationship is most likely causal. (c.f. Correlation does not imply causation) ("See also: Inference to the Best Explanation")

Though a lack of positive evidence can never disprove a hypothesis, a statistically large number of negative instances may make it highly improbable. For example, the lack of success in finding life on Mars, and the lack of a recognizable chemical signature of life, suggests that there is no life on Mars. However, it remains possible that we have not looked in the right place, or not recognized the evidence.

Criteria for selecting the best explanation in this case could involve Occam's razor, which states that the best explanation tends to be the one requiring the fewest additional assumptions. Such an explanation invokes the fewest intermediate factors while maintaining its predictive power; that is, its ability to explain current data and to predict future data. [ [http://experts.about.com/e/n/ne/Negative_proof.htm Negative proof] (experts.about.com)] However, according to the scientific method, the relationship is not formally proven in this instance, and to assert that it is so until disproven is fallacious.

In US criminal law, the lack of reasonable evidence of guilt is the definition of innocenceFact|date=September 2008: A defendant is innocent until proven guilty beyond a reasonable doubt. However, a legal finding of innocence does not mean that the defendant did not commit the crime. It only means that for the purposes of law, the defendant is innocent.

ee also

* Argument from ignorance
* Argument from silence
* Russell's teapot
* Indeterminacy problem

References

External links

* [http://www.safalra.com/philosophy/fallacies/negativeproof/ Negative proof] (safalra.com)