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Muslims do not eat pork.  Fish is pork.  So Muslims don’t eat fish. "Invalid and...

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kandysandy | Student, Undergraduate | eNoter

Posted December 26, 2010 at 2:38 PM via web

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Muslims do not eat pork.  Fish is pork.  So Muslims don’t eat fish. 

"Invalid and unsound arguments."  Could you explain this?

 

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clairewait | High School Teacher | (Level 1) Educator Emeritus

Posted December 26, 2010 at 3:04 PM (Answer #2)

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Upon careful reading of your question, it seems two different ideas are coming into play here.  In logic, an invalid and unsound argument means at least one premise is false and the conclusion does not follow from the premise.  An example of this is explained as follows:

  • All solar satellites are positioned in the ocean. (False)
  • Everything positioned in the ocean becomes wet. (True)
  • Therefore, solar satellites are dry. (??)

The first bullet is the "unsound" premise.  Solar satellites are not positioned in the ocean at all.  The second bullet point is true, but the "dry" part of the conclusion is invalid.  It is completely illogical to conclude that if a solar satellite were in the ocean it would be dry.  Even though the first point is not true, a valid but unsound conclusion would be to say, "Therefore, GPS satellites are wet."  This conclusion logically follows the incorrect argument.  The valid and sound argument is:

  • No solar satellites are positioned in the ocean.
  • Everything positioned in the ocean becomes wet.
  • Therefore, all solar satellites are dry.

The example provided in your question is actually a valid but unsound logical fallacy.  The conclusion is valid, meaning it follows the argument, but one of the premises in the argument is unsound or false.  Notice:

  • Muslims do not eat pork.  (True)
  • Fish is pork. (False)
  • Therefore, Muslims do not eat fish. (Would be true if fish was pork.)

A corrected version of the above argument might be something more like this:

  • Muslims do not eat pork.
  • Bacon is pork.
  • Therefore, Muslims do not eat bacon.
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pohnpei397 | College Teacher | (Level 3) Distinguished Educator

Posted December 27, 2010 at 1:12 PM (Answer #4)

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An argument is valid if the conclusion must follow from the premises.  In this case, if the premises were true, the conclusion would have to be true.  Therefore, this argument actually is valid.

However, this argument is not sound.  An argument is only sound if it is valid and the premises are actually true.  In this case, the premises are not true.  Fish is not pork.

So this is an argument that is valid (it makes sense within itself) but is not sound (not actually true).

Please cut and paste this link if you need more examples:

http://www.iep.utm.edu/val-snd/

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kandysandy | Student, Undergraduate | eNoter

Posted December 27, 2010 at 1:15 PM (Answer #5)

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thank you

could you

  1. Identify the following arguments as:

 

  • Valid and Sound
  • Valid and Unsound
  • Invalid
  1. Muslims do not eat pork. Fish is pork. So Muslims don’t eat fish.
  2. All forms of cheating are ethically wrong. Plagiarism is a form of cheating. Therefore, plagiarism is ethically wrong.
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kandysandy | Student, Undergraduate | eNoter

Posted December 27, 2010 at 1:26 PM (Answer #6)

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thats mean its valid and unsound

 

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kandysandy | Student, Undergraduate | eNoter

Posted December 27, 2010 at 1:33 PM (Answer #7)

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what about #2 All forms of cheating are ethically wrong. Plagiarism is a form of cheating. Therefore, plagiarism is ethically wrong.

could you explain it

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pohnpei397 | College Teacher | (Level 3) Distinguished Educator

Posted December 27, 2010 at 4:27 PM (Answer #8)

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You have two premises:

  • All forms of cheating are ethically wrong
  • Plagiarism is a form of cheating.

You have one conclusion:

  • Therefore, plagiarism is ethically wrong

Apply what I said before:

If your two premises are true, must the conclusion be true?  If so, it is a valid argument.

If it is valid, are the premises true?  If so, it is sound.

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kandysandy | Student, Undergraduate | eNoter

Posted December 28, 2010 at 4:35 AM (Answer #9)

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thank you kindly Mr phonpei379

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mwestwood | College Teacher | (Level 3) Distinguished Educator

Posted December 29, 2010 at 1:36 AM (Answer #10)

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Keep in mind that there are other forms of logical fallacies besides the deductive and inductive syllogisms in which one of the premises may be in error, thus rendering the conclusion invalid.

Red herring is one fallacy often used.  With the red herring, the speaker changes his/her argument to something else in an effort to explain the rational for the first part of the argument.  For instance,

There is some worth to the Republicans tax cut plan.  If the Demoncrats want to survive as a party, they, too, need to show that they are as tough as the Republicans since that is what the public wants. [http://www.nizkor.org/features/fallacies/red-herring.html]

Another fallacy involves an attack upon the speaker--ad hominem.  For example, someone makes a claim, then another person attacks that person's character.  The second person then declares the reasoning of the claim based upon the character of the person.

Person X makes a claim.

Person B attacks Person X

Therefore, person X is wrong.

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kandysandy | Student, Undergraduate | eNoter

Posted December 29, 2010 at 2:38 PM (Answer #11)

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thank you mwestwood
but i can not understand last five lines

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saharm | Student, Undergraduate | Honors

Posted January 6, 2011 at 10:13 AM (Answer #12)

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ofcourse it is not a correct statement that fish is a pork. muslims do not eat pork because it grows up by trashesh and dirty thing and live in a dirty place. it has some microbes in its blood that after eating it and drinking wine it won't have any effect on body but muslims never drinks wine too.

we muslims never eat dirty things and fish is not dirty. because the water in the ocean or sea all the time moves and the sult of this water have the cleaning ability.

we have our religious book like you to know what is correct and what is not correct. our religious book is qoran. if you need more information you can read it.

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ivorynihi | Student, Grade 10 | eNoter

Posted January 20, 2011 at 4:24 AM (Answer #13)

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fish isnt pork!!!!! according 2 ma kwledge......n muslims do eat fish alot it is one of there fav meals.........i do agree they do ot eat bacon at all but hell yea they do eat fish!!!!!

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