To install click the Add extension button. That's it.

The source code for the WIKI 2 extension is being checked by specialists of the Mozilla Foundation, Google, and Apple. You could also do it yourself at any point in time.

4,5
Kelly Slayton
Congratulations on this excellent venture… what a great idea!
Alexander Grigorievskiy
I use WIKI 2 every day and almost forgot how the original Wikipedia looks like.
Live Statistics
English Articles
Improved in 24 Hours
Added in 24 Hours
Languages
Recent
Show all languages
What we do. Every page goes through several hundred of perfecting techniques; in live mode. Quite the same Wikipedia. Just better.
.
Leo
Newton
Brights
Milds

Negative conclusion from affirmative premises

From Wikipedia, the free encyclopedia

Negative conclusion from affirmative premises is a syllogistic fallacy committed when a categorical syllogism has a negative conclusion yet both premises are affirmative. The inability of affirmative premises to reach a negative conclusion is usually cited as one of the basic rules of constructing a valid categorical syllogism.

Statements in syllogisms can be identified as the following forms:

  • a: All A is B. (affirmative)
  • e: No A is B. (negative)
  • i: Some A is B. (affirmative)
  • o: Some A is not B. (negative)

The rule states that a syllogism in which both premises are of form a or i (affirmative) cannot reach a conclusion of form e or o (negative). Exactly one of the premises must be negative to construct a valid syllogism with a negative conclusion. (A syllogism with two negative premises commits the related fallacy of exclusive premises.)

Example (invalid aae form):

Premise: All colonels are officers.
Premise: All officers are soldiers.
Conclusion: Therefore, no colonels are soldiers.

The aao-4 form is perhaps more subtle as it follows many of the rules governing valid syllogisms, except it reaches a negative conclusion from affirmative premises.

Invalid aao-4 form:

All A is B.
All B is C.
Therefore, some C is not A.

This is valid only if A is a proper subset of B and/or B is a proper subset of C. However, this argument reaches a faulty conclusion if A, B, and C are equivalent.[1][2] In the case that A = B = C, the conclusion of the following simple aaa-1 syllogism would contradict the aao-4 argument above:

All B is A.
All C is B.
Therefore, all C is A.

YouTube Encyclopedic

  • 1/3
    Views:
    1 392
    3 996
    1 176
  • ✪ Rule IV (Categorical Syllogisms)
  • ✪ Universal Particular Affirmative Negative
  • ✪ Exclusive Premises (Logical Fallacy)

Transcription

See also

References

  1. ^ Alfred Sidgwick (1901). The use of words in reasoning. A. & C. Black. pp. 297–300.
  2. ^ Fred Richman (July 26, 2003). "Equivalence of syllogisms" (PDF). Florida Atlantic University: 16. Archived from the original (PDF) on June 19, 2010. Cite journal requires |journal= (help)

External links

This page was last edited on 20 March 2020, at 02:10
Basis of this page is in Wikipedia. Text is available under the CC BY-SA 3.0 Unported License. Non-text media are available under their specified licenses. Wikipedia® is a registered trademark of the Wikimedia Foundation, Inc. WIKI 2 is an independent company and has no affiliation with Wikimedia Foundation.