@gjsterp Validity is a feature of deductive reasoning you commonly find in math, formal logic, computer programming, etc. But most reasoning about the world, say, doesn't have this feature. "Invalid argument" doesn't imply "bad argument". Scientific reasoning, detective work, medical diagnosis, etc. is at best strong, rather than valid, but we still think such arguments can count as offering "good reasons" to accept their conclusions.
I've got a tutorial course on how to organize an argumentative essay (see my channel), and a lot of that material is relevant to essay writing in general, but I don't have anything on english composition, grammar, etc. Sorry. Thanks for the nice comment.
@Heissenburger Very true! But in very different ways. The traditional notion of "logical strength" trades on the notion that belief or logical support can come in degrees, but retains bivalence (a proposition can only take on one of two truth values, "true" and "false"). Fuzzy logics trade on the notion that membership in a set can come in degrees, and correspondingly that truth values can come in degrees as well.
@socrates856 If we modify the conclusion as you suggest, then it's no longer an invalid argument (it's no longer a "risky" inference). The concept of a strong argument is meant to capture a risky inference (the conclusion doesn't follow with necessity) but that nevertheless it would be reasonable to accept. But the question of where to assign the probability (to the conclusion or to the inference as a whole) is an interesting one.
@socrates856 Strictly speaking, you can't have an argument that is both valid and strong, since strong arguments are by definition invalid. The terms 'valid' and 'invalid', and 'strong' and 'weak', are all used to describe the logical properties of an inference, they imply nothing about the actual truth or falsity of the premises themselves. In standard terminology, a valid argument with all true premise is called 'sound'; a strong argument with all true premises is called 'cogent'.
These arguments are ALL SO COMPLEX! I think it would be easier to just SCREAM my point(s) yet I have to learn how to do them to pass US HISTORY! Grrrr! Screaming is how I argue! The LOUDEST ONE usually wins!
Hi Kevin, Thanks for clearly explaining things. This video raises interesting questions. Are strong arguments invalid? When we look at the definition, that certainly is true, but do logicians use the terms that way? It seems strange to say that a strong argument is invalid; just as it would be strange to say that a valid argument is strong. I thought strong is a property of induction while valid is a term used only for deduction. Is that wrong? Is your point that the definition of validity unfortunately includes these examples, or is that how we use these terms? Does strong refer to induction while valid applies to deduction? If this is the case, then we need a better definition of validity. Here is another problem with the definition of validity. There are invalid arguments where the conclusion can't be false, but the definition makes them valid. Some propositions can't be false - like 1 + 1 = 2. Conclusions of this sort make any argument valid by definition as it's impossible to have all true premises and a false conclusion because it's impossible to have a false conclusion. Do logicians refer to statements that can't be false as valid, or is this an improper use of the language? Thanks again, John
Think about it this way: If C is A, then the argument I presented in my last post could be rewritten as "Almost all C are B, therefore C is B." That argument blatantly makes no logical sense what so ever. It is no better, logically, than saying "almost no C are B, therefore C is B". The conclusion is an absolute statement, "C is B". Not "C is likely B". It is simply an incorrect conclusion.
Great video. Made the distinction between valid, strong and weak arguments clear to me. However, I think it would have been a good idea to mention 'sound arguments' also (where the argument is valid AND the premises are true). From the worst type of argument to the best one could list: weak, strong, valid, sound. Thanks
Hey Kevin, you said that for a an argument to be valid it must satisfy the logic condition i.e. that must follows from the premises but this is contrary to what you said in respect of strong argument where it didn't satisfy the logic condition and hence not a valid argument but you said that it satisfied the logic condition.
But we studied that we can talk about validity and invalidity only when we want to evaluate the the deductive argument. Could you please clarify more please and thanks a lot🌹❤️
The colunm on the right sound more like inductive arguments and the ones on the left are deductive arguments. I think inductive argument is a better term then strong argument.
I like how u explain ur thoughts and judgements. If u have any resources to help improve my english especially for essay writing, it would be very appreciated.
Question: What about when one stipulates a 'highliy valid' and 'not very valid arguments'? Does this make the word just a matter of degree - similar to a 'strong' or 'weak' argument?
How can a "strong" argument be considered "good"? I don't consider it reasonable to believe a claim that something is TRUE simply because it is LIKELY. Those are extremely different things, and I would consider, in normal conversation, an argument such as "Almost all A are B, C is A, therefore C is B" to be a very very bad argument. I can't see how it would be useful, in a practical sense, to regard something as illogical as that as being "good".
I appreciate this series. One question though, wouldn’t most arguments be considered invalid since absolute certainty, about anything, is near impossible to obtain? The sun rising is 99.999... likely to happen but we can’t be absolutely certain; therefore any argument with the premise guaranteeing a sunrise is automatically invalid. No?
This is confusing because deductive arguments are intended to be valid by the author, whereas inductive arguments are intended to be reliable by the author. I feel like you're combining the two in this vid. The example you showed with the percentages is a statistical syllogism. P% of A are B, x is A, therefore x is B.
i think my teacher is teaching us wrong. she said only deductive arguments can be valid/invalid. but inductive arguments can be strong or weak. she doesn't understand logical fallacies either and she's teaching us wrong
90% of humans are right-handed Pat is human Therefore, Pat is right-handed It is a STRONG Argument. But if I change the conclusion to: " Therefore, Pat is most likely to be right-handed.", does it make it a valid argument?
this stuff would make great replies to conspiracy theories, most of those arguments don't even qualify as weak, something like 10 to 20 percent which makes it not only invalid but practically BS
Basically what I'm saying is, the definition of "good" that you're providing seems rather useless and silly. What's the point of calling an argument "good" if it includes "strong" conclusions?
Completely arbitrary!! Brings nobody closer to knowing, proving, or learning anything. Personal invocations of 'strong' and 'weak' do nothing to ameliorate the problem and arguing that such things 'strong' and 'weak' even exist is even a bigger hurdle to jump than the problems which their invocations attempt to solve. Get out of here.
13 years later, still helpful. Thank you!
@gjsterp Validity is a feature of deductive reasoning you commonly find in math, formal logic, computer programming, etc. But most reasoning about the world, say, doesn't have this feature. "Invalid argument" doesn't imply "bad argument". Scientific reasoning, detective work, medical diagnosis, etc. is at best strong, rather than valid, but we still think such arguments can count as offering "good reasons" to accept their conclusions.
I've got a tutorial course on how to organize an argumentative essay (see my channel), and a lot of that material is relevant to essay writing in general, but I don't have anything on english composition, grammar, etc. Sorry. Thanks for the nice comment.
Amazing! Brilliantly explained..
@Heissenburger Very true! But in very different ways. The traditional notion of "logical strength" trades on the notion that belief or logical support can come in degrees, but retains bivalence (a proposition can only take on one of two truth values, "true" and "false"). Fuzzy logics trade on the notion that membership in a set can come in degrees, and correspondingly that truth values can come in degrees as well.
@socrates856 I really appreciate you taking the time to comment! Thanks!
@socrates856 If we modify the conclusion as you suggest, then it's no longer an invalid argument (it's no longer a "risky" inference). The concept of a strong argument is meant to capture a risky inference (the conclusion doesn't follow with necessity) but that nevertheless it would be reasonable to accept. But the question of where to assign the probability (to the conclusion or to the inference as a whole) is an interesting one.
@socrates856 Strictly speaking, you can't have an argument that is both valid and strong, since strong arguments are by definition invalid. The terms 'valid' and 'invalid', and 'strong' and 'weak', are all used to describe the logical properties of an inference, they imply nothing about the actual truth or falsity of the premises themselves. In standard terminology, a valid argument with all true premise is called 'sound'; a strong argument with all true premises is called 'cogent'.
These arguments are ALL SO COMPLEX! I think it would be easier to just SCREAM my point(s) yet I have to learn how to do them to pass US HISTORY! Grrrr! Screaming is how I argue! The LOUDEST ONE usually wins!
Yes, if you don't mind other people thinking you can't even come up with a better argument than that. Earplugs are a thing you know.
I watched this video on Sunday, June 22nd for my developmental reading class.
dang 5 yrs ago
Very well explained
Hi Kevin,
Thanks for clearly explaining things. This video raises interesting questions. Are strong arguments invalid? When we look at the definition, that certainly is true, but do logicians use the terms that way? It seems strange to say that a strong argument is invalid; just as it would be strange to say that a valid argument is strong. I thought strong is a property of induction while valid is a term used only for deduction. Is that wrong? Is your point that the definition of validity unfortunately includes these examples, or is that how we use these terms? Does strong refer to induction while valid applies to deduction? If this is the case, then we need a better definition of validity.
Here is another problem with the definition of validity. There are invalid arguments where the conclusion can't be false, but the definition makes them valid. Some propositions can't be false - like 1 + 1 = 2. Conclusions of this sort make any argument valid by definition as it's impossible to have all true premises and a false conclusion because it's impossible to have a false conclusion. Do logicians refer to statements that can't be false as valid, or is this an improper use of the language?
Thanks again,
John
Wow wish you could help me understand more
Think about it this way: If C is A, then the argument I presented in my last post could be rewritten as "Almost all C are B, therefore C is B." That argument blatantly makes no logical sense what so ever. It is no better, logically, than saying "almost no C are B, therefore C is B". The conclusion is an absolute statement, "C is B". Not "C is likely B". It is simply an incorrect conclusion.
@thesparitan i consider that a great compliment indeed, thank you!
If invalid and all false premises can we conclude false conclusion or can it be true conclusion too ?
Why can't you have subtitles that I can copy & paste to print off and take with me? Some people do and it's very helpful. Thank you.
...Because the video is 13 years old?
It makes a difference if you ask for free help with "Could you..?" instead of "Why can't you..?"..
Great video. Made the distinction between valid, strong and weak arguments clear to me. However, I think it would have been a good idea to mention 'sound arguments' also (where the argument is valid AND the premises are true). From the worst type of argument to the best one could list: weak, strong, valid, sound.
Thanks
Your videos are great for people studying for debate!
Hey Kevin, you said that for a an argument to be valid it must satisfy the logic condition i.e. that must follows from the premises but this is contrary to what you said in respect of strong argument where it didn't satisfy the logic condition and hence not a valid argument but you said that it satisfied the logic condition.
So valid and invalid are absolute, binary designations and weak or strong are a spectrum of intermediaries.
thanks, this helped me get an 83% on my civics essay / slideshow
But we studied that we can talk about validity and invalidity only when we want to evaluate the the deductive argument. Could you please clarify more please and thanks a lot🌹❤️
The colunm on the right sound more like inductive arguments and the ones on the left are deductive arguments. I think inductive argument is a better term then strong argument.
I like how u explain ur thoughts and judgements. If u have any resources to help improve my english especially for essay writing, it would be very appreciated.
Question: What about when one stipulates a 'highliy valid' and 'not very valid arguments'? Does this make the word just a matter of degree - similar to a 'strong' or 'weak' argument?
Great video, would have helped if text were readable though...
How can a "strong" argument be considered "good"? I don't consider it reasonable to believe a claim that something is TRUE simply because it is LIKELY. Those are extremely different things, and I would consider, in normal conversation, an argument such as "Almost all A are B, C is A, therefore C is B" to be a very very bad argument. I can't see how it would be useful, in a practical sense, to regard something as illogical as that as being "good".
Lol why this in my recommendation... Might come in handy tho
I appreciate this series. One question though, wouldn’t most arguments be considered invalid since absolute certainty, about anything, is near impossible to obtain? The sun rising is 99.999... likely to happen but we can’t be absolutely certain; therefore any argument with the premise guaranteeing a sunrise is automatically invalid. No?
You could say that argument B is statistically strong and therefore the conclusion has a relatively high probability of being true.
This is confusing because deductive arguments are intended to be valid by the author, whereas inductive arguments are intended to be reliable by the author. I feel like you're combining the two in this vid. The example you showed with the percentages is a statistical syllogism. P% of A are B, x is A, therefore x is B.
the video was very helpful! thank you!
i think my teacher is teaching us wrong. she said only deductive arguments can be valid/invalid. but inductive arguments can be strong or weak. she doesn't understand logical fallacies either and she's teaching us wrong
this is correct tho
I love it! Thanks!
Relativity?
Fuzzy logic provides another calculus to handle different degrees of certainty.
en(dot)wikipedia(dot)org(slash)wiki(slash)Fuzzy_logic
90% of humans are right-handed
Pat is human
Therefore, Pat is right-handed
It is a STRONG Argument.
But if I change the conclusion to: " Therefore, Pat is most likely to be right-handed.", does it make it a valid argument?
The first statement was likely to be true, but the second statement (your statement) makes it a bit more true because pat could also be left handed.
@@qryx0538 isn't every proposition either true or its negation is true?
Wrong
Istasis Mishra nope that’s like saying 99% of the money is paid so it is paid of almost
this stuff would make great replies to conspiracy theories, most of those arguments don't even qualify as weak, something like 10 to 20 percent which makes it not only invalid but practically BS
If an argument is invalid logically, as these two are, how can one ever be considered "strong"?
Still good.
Basically what I'm saying is, the definition of "good" that you're providing seems rather useless and silly. What's the point of calling an argument "good" if it includes "strong" conclusions?
Great video Kevin, so is Pat male or female?LOL
A true PhilosophyFreak, ;D thanks for the help! recpect!
Most = >50%
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Completely arbitrary!! Brings nobody closer to knowing, proving, or learning anything. Personal invocations of 'strong' and 'weak' do nothing to ameliorate the problem and arguing that such things 'strong' and 'weak' even exist is even a bigger hurdle to jump than the problems which their invocations attempt to solve. Get out of here.
Strong arguments
sound like weak logic to me.
90% sounds very low to me.
I would think that 99% would be a minimum.
On steroids