Difference between revisions of "Contradiction"
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| − | In a [[proof]], if two contradictory [[inference]]s can be drawn from the [[premise]], this indicates either that a premise is false or that the argument is invalid. | + | In a [[proof]], if two contradictory [[Conclusion|inference]]s can be drawn from the [[premise]], this indicates either that a premise is false or that the argument is invalid. |
It is often held that from a contradiction anything can be inferred. This can be demonstrated: | It is often held that from a contradiction anything can be inferred. This can be demonstrated: | ||
Revision as of 16:35, March 23, 2018
A contradiction is the simultaneous acceptance and denial of a proposition or statement. "It was the best of times and the worst of times" is a poetic example: the contradiction is being used to enhance the poetic nature of the piece.
According to J.Sarfati, a contradiction is defined as the conjunction of the affirmation and denial of a premise, in the same time, place, and sense (i.e. p and not-p, or in symbolic form, p.~p).[1]
In a proof, if two contradictory inferences can be drawn from the premise, this indicates either that a premise is false or that the argument is invalid.
It is often held that from a contradiction anything can be inferred. This can be demonstrated:
- Take any contradiction, “A” and “Not A”, and take it to be true.
- Take anything that you want to prove, “P”
- Now because “A and Not A” is true, “A” is true, by virtue of the simplification rule.
- “A or P” is true just so long as not both A and P are false.
- So, As “A” is true, “A or P” must be true.
- If “A or P” is true, then one of “A” or “P” must be true.
- As “Not A” is true then “A” is false which means that the remaining term in “A or P” must be true.
- “P”, absolutely anything you like, is true.
References
- ↑ Jonathan Sarfati (4 November 2012). Is God a particle-wave duality?. Creation Ministries International. Retrieved on 2012-11-04.