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# Deductive Arguments

 Posts: 3,881 Add as FriendChallenge to a DebateSend a Message 5/30/2014 8:36:22 AMPosted: 3 years agoThe other arm of modus tollens are modus ponuns arguments, which I find less useful, but still a valid form of argument they go by the form:1. If X, then Y2. XC. Y1. If I push tbhidc over a cliff, he will die2. I pushed tbhidc over a cliffC. Tbhidc diedWhat you will more commonly see though is the fallacious denying the antecedent argument:1. If X, then Y2. Not XC. Not Y1. If I push tbhidc over a cliff, he will die2. I didn't push tbhidc over a cliff3. Tbhidc did not dieWhen of course, there are other conditions which may produce the outcome Y.
 Posts: 1,023 Add as FriendChallenge to a DebateSend a Message 5/30/2014 10:08:32 AMPosted: 3 years agoAt 5/30/2014 10:02:29 AM, Mhykiel wrote:That's what valid means. A probability of being true. You just rewarded the distinction I made.No. If an argument is logically valid, then if the conclusion must be true if the premises are true -- not the conclusion is probably true.
 Posts: 6,138 Add as FriendChallenge to a DebateSend a Message 5/30/2014 10:16:46 AMPosted: 3 years agoAt 5/30/2014 10:08:32 AM, Enji wrote:At 5/30/2014 10:02:29 AM, Mhykiel wrote:That's what valid means. A probability of being true. You just rewarded the distinction I made.No. If an argument is logically valid, then if the conclusion must be true if the premises are true -- not the conclusion is probably true.It would be nice if both of you looked up the word "Valid"Not logically valid or valid argument, but the word itself.Valid: having a sound basis in logic or fact; reasonable or cogentnotice the words sound, reasonable, cogent.... NONE of those mean certain.
 Posts: 6,138 Add as FriendChallenge to a DebateSend a Message 5/30/2014 10:21:49 AMPosted: 3 years agoInductive arguments conclude with a "valid" statement. Meaning the conclusion is reasonable and likely or highly probable. Not just that there is a probability or possibility of it being true, but that it is a high chance of it being true.Deductive arguments conclude with a "certain" or assured statement. The conclusion should follow from the truth of the premises. True premises make it necessary to have the a true conclusion.
 Posts: 1,023 Add as FriendChallenge to a DebateSend a Message 5/30/2014 10:31:11 AMPosted: 3 years agoAt 5/30/2014 10:16:46 AM, Mhykiel wrote:At 5/30/2014 10:08:32 AM, Enji wrote:At 5/30/2014 10:02:29 AM, Mhykiel wrote:That's what valid means. A probability of being true. You just rewarded the distinction I made.No. If an argument is logically valid, then if the conclusion must be true if the premises are true -- not the conclusion is probably true.It would be nice if both of you looked up the word "Valid"Not logically valid or valid argument, but the word itself.Valid: having a sound basis in logic or fact; reasonable or cogentnotice the words sound, reasonable, cogent.... NONE of those mean certain.You can't just take a word which has a well defined meaning pertaining to the topic of the thread and then say "but not that meaning." See definition 2b [http://www.merriam-webster.com...]. In logic, an argument is valid if the conclusion necessarily follows from the premises due to the axioms of logic -- 'valid' is an adjective describing the structure of an argument, and it describes deductive arguments. The conclusion of an inductive argument does not necessarily follow from the premises, so valid isn't an adjective used to describe inductive arguments; inductive arguments are instead strong or weak, which reflects the likelihood of the conclusion being true.
 Posts: 6,138 Add as FriendChallenge to a DebateSend a Message 5/30/2014 10:33:55 AMPosted: 3 years agoAt 5/30/2014 10:31:11 AM, Enji wrote:At 5/30/2014 10:16:46 AM, Mhykiel wrote:At 5/30/2014 10:08:32 AM, Enji wrote:At 5/30/2014 10:02:29 AM, Mhykiel wrote:That's what valid means. A probability of being true. You just rewarded the distinction I made.No. If an argument is logically valid, then if the conclusion must be true if the premises are true -- not the conclusion is probably true.It would be nice if both of you looked up the word "Valid"Not logically valid or valid argument, but the word itself.Valid: having a sound basis in logic or fact; reasonable or cogentnotice the words sound, reasonable, cogent.... NONE of those mean certain.You can't just take a word which has a well defined meaning pertaining to the topic of the thread and then say "but not that meaning." See definition 2b [http://www.merriam-webster.com...]. In logic, an argument is valid if the conclusion necessarily follows from the premises due to the axioms of logic -- 'valid' is an adjective describing the structure of an argument, and it describes deductive arguments. The conclusion of an inductive argument does not necessarily follow from the premises, so valid isn't an adjective used to describe inductive arguments; inductive arguments are instead strong or weak, which reflects the likelihood of the conclusion being true.You can not just twist my words around. I was not saying logically valid at all.I said the conclusion of a inductive argument is valid/invalid.So Valid is an adjective applied to the word conclusion. Not applied to the word argument.SO what is the definition of a valid conclusion?. The definition I gave.Learn to read english.
 Posts: 6,138 Add as FriendChallenge to a DebateSend a Message 5/30/2014 10:39:55 AMPosted: 3 years agoThe previous examples are not all deductive arguments. A deductive argument is that if the premises are true the conclusion has to be true. In a deductive argument there is no way for the premises to be true and the conclusion false.If you look at the previous examples you can see the conclusion could be false or true even if all the premises were true. That makes those examples inductive.Deductive Arguments:Modus Ponens:1. If P, then Q2. P3. Therefore Q1. If the dog is muddy, then the dog will leave muddy footprints2. the dog is muddy3. Therefore the dog leaves muddy foot prints.The conclusion is "definite", "100% certain", or "completely True" IF the premises are true AND X is necessary for Y. You will see this structure often but it is not a deductive argument if X is not necessary for Y. So the relationship between X and Y is one of subsequential, parent-child, cuase-effect.Modus Tollens:1. If P, then Q2. not Q3. not P1. If there is a fire detected, then a working fire alarm will buzz.2.No fire alarm is buzzing3. No fire detectedNotice with the negative it is like Modus Pollens except now the relationship is inverse. P has to have Q. So if no Q then No P.Pollens is affirming PTollens is negating QIn Pollens Q requires P to exist.In Tollens P requires Q for P to exist.
 Posts: 1,023 Add as FriendChallenge to a DebateSend a Message 5/30/2014 10:42:06 AMPosted: 3 years agoAt 5/30/2014 10:33:55 AM, Mhykiel wrote:At 5/30/2014 10:31:11 AM, Enji wrote:At 5/30/2014 10:16:46 AM, Mhykiel wrote:At 5/30/2014 10:08:32 AM, Enji wrote:At 5/30/2014 10:02:29 AM, Mhykiel wrote:That's what valid means. A probability of being true. You just rewarded the distinction I made.No. If an argument is logically valid, then if the conclusion must be true if the premises are true -- not the conclusion is probably true.It would be nice if both of you looked up the word "Valid"Not logically valid or valid argument, but the word itself.Valid: having a sound basis in logic or fact; reasonable or cogentnotice the words sound, reasonable, cogent.... NONE of those mean certain.You can't just take a word which has a well defined meaning pertaining to the topic of the thread and then say "but not that meaning." See definition 2b [http://www.merriam-webster.com...]. In logic, an argument is valid if the conclusion necessarily follows from the premises due to the axioms of logic -- 'valid' is an adjective describing the structure of an argument, and it describes deductive arguments. The conclusion of an inductive argument does not necessarily follow from the premises, so valid isn't an adjective used to describe inductive arguments; inductive arguments are instead strong or weak, which reflects the likelihood of the conclusion being true.You can not just twist my words around. I was not saying logically valid at all.I said the conclusion of a inductive argument is valid/invalid.So Valid is an adjective applied to the word conclusion. Not applied to the word argument.SO what is the definition of a valid conclusion?. The definition I gave.Learn to read english.A deductive argument is described in terms of validity and soundness. An inductive argument is described in terms of strength and congency. You're using the wrong words.
 Posts: 3,881 Add as FriendChallenge to a DebateSend a Message 5/30/2014 10:47:10 AMPosted: 3 years agoAt 5/30/2014 10:39:55 AM, Mhykiel wrote:The previous examples are not all deductive arguments. A deductive argument is that if the premises are true the conclusion has to be true. In a deductive argument there is no way for the premises to be true and the conclusion false.If you look at the previous examples you can see the conclusion could be false or true even if all the premises were true. That makes those examples inductive.Deductive Arguments:Modus Ponens:1. If P, then Q2. P3. Therefore Q1. If the dog is muddy, then the dog will leave muddy footprints2. the dog is muddy3. Therefore the dog leaves muddy foot prints.The conclusion is "definite", "100% certain", or "completely True" IF the premises are true AND X is necessary for Y. You will see this structure often but it is not a deductive argument if X is not necessary for Y. So the relationship between X and Y is one of subsequential, parent-child, cuase-effect.Modus Tollens:1. If P, then Q2. not Q3. not P1. If there is a fire detected, then a working fire alarm will buzz.2.No fire alarm is buzzing3. No fire detectedNotice with the negative it is like Modus Pollens except now the relationship is inverse. P has to have Q. So if no Q then No P.Pollens is affirming PTollens is negating QIn Pollens Q requires P to exist.In Tollens P requires Q for P to exist.+1 on Enji, and I didn't give any invalid examples unless I specifically said it was invalid. Such as affirming the consequent or denying the antecedent .
 Posts: 1,023 Add as FriendChallenge to a DebateSend a Message 5/30/2014 11:03:59 AMPosted: 3 years agoAt 5/30/2014 10:52:29 AM, Mhykiel wrote:At 5/30/2014 10:42:06 AM, Enji wrote:A deductive argument is described in terms of validity and soundness. An inductive argument is described in terms of strength and congency. You're using the wrong words.No you are completely wrong.A valid argument or a logically valid argument is a description of a sound structure.a deductive argument leads to a conclusion that is a certainty, fact, truea inductive leads to a conclusion that is valid, probable, cogentWhat I am saying is no different than in every philosophy 101 class. here is just one site out of thousands to help you understand: http://philosophy.lander.edu...Your source doesn't support what you are claiming. It uses validity to describe only deductive arguments, and points out that inductive arguments aren't necessarily deductively valid. Validity, soundness, strength, and cogency are terms which should have been covered in whichever philosophy or logic class you took. Here's the top 3 websites Google found:http://editthis.info...http://www.uky.edu...http://itdc.lbcc.edu...
 Posts: 84 Add as FriendChallenge to a DebateSend a Message 5/30/2014 11:09:42 AMPosted: 3 years agoA valid argument has nothing to do with the truth of the premises. That's completely different. Sure, you could use the word "valid" to mean more likely true than not, but usually "validity" refers to the structure of the argument.To quote GK Chesterton..." Logic and truth, as a matter of fact, have very little to do with each other. Logic is concerned merely with the fidelity and accuracy with which a certain process is performed, a process which can be performed with any materials, with any assumption. You can be as logical about griffins and basilisks as about sheep and pigs...Logic, then, is not necessarily an instrument for finding truth; on the contrary, truth is necessarily an instrument for using logic"for using it, that is, for the discovery of further truth and for the profit of humanity. Briefly, you can only find truth with logic if you have already found truth without it."