If you are a Jedi, Then you use the Force. Dooku uses the Force. Dooku is a Jedi.
This is INVALID--
Lawgic:
Jedi-> Force
Dooku -> Force
Dooku -> Jedi
Imagine two circles, small circle being Jedi and it's inside the Force.... Dooku can be anything other than a Jedi and still be in the big circle "Uses the force".
This would be a VALID argument:
Only Jedi use the Force. Dooku uses the Force. Therefore, Dooku is a Jedi.
(remember Only is group 2 indicator)
Lawgic:
Force -> Jedi
Dooku -> Force
Dooku -> Jedi
Lets chain this up:
Dooku -> Force -> Jedi
so...
Dooku -> Jedi
Because Dooku uses the Force and thats sufficient to be a Jedi than that makes sense as he's already in the small circle so he must be a Jedi.
I completely understand it but I wish you guys wouldn’t show the invalid argument in lawgic. When you’re still trying to grasp everything it’s easy to see and have it manipulate your thinking, even when you know it’s wrong.
So if the premise said "Only Jedi use the Force", would that mean that Jedi is the necessary condition and Force is the sufficient? In Lawgic it would be written as Force -> Jedi
The replacing of all and only is definitely the best way to think of this if you are struggling with sufficiency and necessity. It follows that even if "All" in the first argument, the predicate does not require the subject to be it. "Some" narrows the scope, in turn creating a valid argument.
I understand this and the previous bc he used star wars again making the translation easier to dissect. Wording should be reworked on both but if you are confused on the language, he is saying the second example is an incorrect translation into lawgic, but because of that, it does make it a valid argument, however that is NOT what the statements are saying and you will pick a wrong answer.
@VanillaCat great way to visualize is the circles example: necessary is the bigger circle, sufficient is the smaller circle within the bigger one. Sufficient is always in the necessary's circle, but the necessary's circle can have other sufficients inside it as well
@VanillaCat Wait I am a little confused about the second bullet point... how can failing the necessary not guarantee failing the sufficient?
Going back to a previous example of NYC -> USA... if I do not satisfy USA, then I cannot satisfy NYC.
I understand you can satisfy NYC if your necessary is New York or East Coast, is that what you are explaining? That they are other methods of satisfying the sufficient?
@Kellbell206 hello yes the second one just refers to /USA --> /NYC. i'm a little confused what you are asking, if the necessary is NY, then yes NYC or East Coast could be sufficient conditions. but if we are looking at relationship between NYC and USA, failing the necessary (USA) means there's no possible way we could meet the sufficient (NYC). mayb your first sentence is where confusion lies? failing the necessary DOES guarantee we failed the sufficient (failing to be in USA does guarantee failing to be in NYC). 😊
I don't understand the last paragraph "The only problem is that you made up your own premise B -> A. The actual premise is A -> B. You confused sufficiency for necessity."
The rest of the lesson makes sense, but I'm totally lost when I read that. Maybe make a video or remove/clarify that paragraph? I don't see what that really adds here.
@john Agreed that confused me. I think they're just saying that the conditional argument follows A--> B, xA, xB. They chose to flip it for the sake of correcting the example but it does not follow the traditional (correct) conditional argument sequence.
Valid conclusion: Only dogs play outside. Blanche plays outside. Therefore, Blanche is a dog.
Invalid conclusion: All dogs play outside. Blanche plays outside. Therefore, Blanche is a dog.
In the invalid conclusion, Blanche could be a part of another group since it does not explicitly state that you have to be a dog to play outside. She could be human, a cat, etc.
Ok so I also found this lesson confusing. What I think the key take away here is that just because the necessary condition is true tells us nothing about the sufficient condition. That's it.
My example:
All moms use the kitchen. I use the kitchen. Therefore, I am a mom
Lawgic:
Moms -> use kitchen
I KITCHEN
--
I MOM
This is Invalid. WHY? Because I'M NOT A MOM. I AM A SINGLE DUDE. Just because I am using the kitchen does that mean I am a mom? NO!
If you thought me using the kitchen meant I'm a mom you are confusing sufficiency for necessity. You are saying that using the kitchen is SUFFICENT for being a mom. you are saying "All those who use the kitchen are mom".
AFFIRMING THE NECESSARY CONDITION TELLS YOU NOTHING ABOUT THE SUFFICIENT CONDITION
All we know from the stimulus is that All moms use the kitchen.
Mom = Sufficient
Using kitchen = Necessary
If I affirm the necessary condition by saying "I use the kitchen" does that tell you anything about if I am a mom or not?
If the necessary condition is satisfied, it yields no information about the sufficient condition. The sufficient condition could be true or could be false.
"All" is from group 1-necessity conditional indicators, where what follows immediately after the indicator, in this case "all", is the necessary condition. So, lawgic would be:
All Jedi use the Force.
J -> F
Dooku use force:
D -> F
Dooku is Jedi:
D -> J. This conclusion is not valid from the given premise.
In case of "only", its from group 2-sufficiency conditional indicators. What follows immediately after the indicator, "only", is the sufficient condition. So, lawgic would be:
Only Jedi use the Force.
F -> J
Dooku uses the Force.
D -> F
Chaining conditionals:
D -> F -> J
D -> J
We can infer from the above that Dooku is Jedi, which is the conclusion in the argument.
What has made this easier for me is realizing that all is not the same as only. All refers to everything of a certain group. Only is more strict about the rules.
All dogs drink water. Other animals can drink water too.
ONLY dogs drink water. No other animals drink water.
I am also confused by this but I am a little new to studying for this oldest trick in the book that keeps kicking my butt.
All Jedi… Is that not a sufficient condition because they used “all”? All Jedi us the force so using the force is a sufficient condition of being a Jedi?
Only Jedi…is that not a necessary condition because they used “only”? While using the force is a necessary condition of being a Jedi it is not sufficient to guarantee membership in the Jedi order simply because one uses the force?
@DorinLee Hi I don't know if this is helpful but I think by the statement "the only problem is that you made up your own premise" they mean that you alone had to assume that B-->A to make the conclusion valid. The stimulus only tells you that A--> B. The only way to make this conclusion valid is to add in this premise you made up (B--> A). So the conclusion is not valid given the premises the stimulus gives you.
Only Arabic-speakers get PhDs. Chris is an Arabic speaker. Therefore Chris gets a PhD.
If gets a PhD, then an Arabic Speaker, written
PhD->Arabic-speaker
Now here's where you don't want to mess up. It says Chris is in that "Arabic-Speaker" portion, or in other words, he's someone in the necessary condition position. But we can't work backwards. We can't say if Chris (the necessary) speaks Arabic then he gets a PhD.
It's easier to see if we use three topics, as it builds on earlier lessons:
Would you say this can be simplified to: "If the sufficient condition is false, the necessary condition can be true or false", and "if the necessary condition is true, the sufficient condition can be true or false"?
I do not understand the second example. If the conditional indicator is Only, that translates to logic Uses Force --> Jedi. Since Dooku uses the force, he triggered the sufficient and is a Jedi. This is a valid logic. But why did the text say I made up my own premise? If the conditional indicator is only, I did not make anything up did I? it's very confusing.
If it says all jedi use the force, and count doku uses the force. Its reasonable to assume that hes a jedi based on the premises. Dont understand why thats not valid
If all Jedi USE the force, that just means that all Jedi have the ability to use it. It doesn't say anything about if Sith can use it, etc. Because we just don't know if others can use it, it's not valid. Count Dooku might as well be a force user, but not a Jedi. That possibility still exists.
Another example:
All dogs like peanut butter. Jim likes peanut butter. Does this mean Jim is a dog? He might not be, right? It's not a requirement to be a dog to like peanut butter. There's a bit of a hole in that argument.
If the argument was ONLY Jedi use the force, then yes the argument would be valid. Just because All Jedi use the force doesn't mean all force-users are Jedi.
All birds eat corn. Rob eats corn. Therefore, Rob is a bird.
This is invalid because Rob could be a human, a dog, a raccoon, anything.
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141 comments
I hope this helps:
(if, then always helped me)
If you are a Jedi, Then you use the Force. Dooku uses the Force. Dooku is a Jedi.
This is INVALID--
Lawgic:
Jedi-> Force
Dooku -> Force
Dooku -> Jedi
Imagine two circles, small circle being Jedi and it's inside the Force.... Dooku can be anything other than a Jedi and still be in the big circle "Uses the force".
This would be a VALID argument:
Only Jedi use the Force. Dooku uses the Force. Therefore, Dooku is a Jedi.
(remember Only is group 2 indicator)
Lawgic:
Force -> Jedi
Dooku -> Force
Dooku -> Jedi
Lets chain this up:
Dooku -> Force -> Jedi
so...
Dooku -> Jedi
Because Dooku uses the Force and thats sufficient to be a Jedi than that makes sense as he's already in the small circle so he must be a Jedi.
I completely understand it but I wish you guys wouldn’t show the invalid argument in lawgic. When you’re still trying to grasp everything it’s easy to see and have it manipulate your thinking, even when you know it’s wrong.
So if the premise said "Only Jedi use the Force", would that mean that Jedi is the necessary condition and Force is the sufficient? In Lawgic it would be written as Force -> Jedi
@mayamcd125 Yes exactly
@mayamcd125 yes. "only" is the necessary indicator word so the sentence should be translated into lawgic as Force -> Jedi
The replacing of all and only is definitely the best way to think of this if you are struggling with sufficiency and necessity. It follows that even if "All" in the first argument, the predicate does not require the subject to be it. "Some" narrows the scope, in turn creating a valid argument.
A trick that may work for people is thinking about this chronologically/left-to-right.
If A > B, then A has to be true before we can conclude that B is true.
If A is false, who knows anything about B. We haven't gotten there yet.
If B is true, great, but we haven't heard about A. We don't know anything about A.
@NikkiWidra This helped a lot! thank youuuu!
For those who have never seen Star Wars (me):
(1) All pilots can fly airplanes. Alex can fly airplanes. Therefore, Alex is a pilot.
This is invalid because someone could know how to fly planes and not be a pilot.
(2) Only pilots can fly airplanes. Alex can fly airplanes. Therefore, Alex is a pilot.
This is valid because anyone who can fly airplanes must be a pilot.
@KaraSwider You need to see Star Wars, nonnegotiable. Thanks for the example though.
@KaraSwider Thank you!!!
I understand this and the previous bc he used star wars again making the translation easier to dissect. Wording should be reworked on both but if you are confused on the language, he is saying the second example is an incorrect translation into lawgic, but because of that, it does make it a valid argument, however that is NOT what the statements are saying and you will pick a wrong answer.
I don't understand this same example used here again saying you made up your own premise. double confusion.
After reading these I think that the videos help me grasp it more.
I got home from reviewing demands and medical records to come and read! ughhh where are the videos!!
@LauraBolivar why is this me!!
@jrm98 Because you're responsible lol that's my best guess right now
Failing a sufficient condition doesn't mean they cannot meet the necessary condition
Failing a necessary condition does mean that they cannot meet the sufficient condition
Meeting a sufficient condition does mean that they meet the necessary condition
Meeting a necessary condition does not mean that they meet the sufficient condition
@VanillaCat needed this!
@VanillaCat great way to visualize is the circles example: necessary is the bigger circle, sufficient is the smaller circle within the bigger one. Sufficient is always in the necessary's circle, but the necessary's circle can have other sufficients inside it as well
@epayne17 Yesss this is what i picture every time
@VanillaCat Wait I am a little confused about the second bullet point... how can failing the necessary not guarantee failing the sufficient?
Going back to a previous example of NYC -> USA... if I do not satisfy USA, then I cannot satisfy NYC.
I understand you can satisfy NYC if your necessary is New York or East Coast, is that what you are explaining? That they are other methods of satisfying the sufficient?
@Kellbell206 hello yes the second one just refers to /USA --> /NYC. i'm a little confused what you are asking, if the necessary is NY, then yes NYC or East Coast could be sufficient conditions. but if we are looking at relationship between NYC and USA, failing the necessary (USA) means there's no possible way we could meet the sufficient (NYC). mayb your first sentence is where confusion lies? failing the necessary DOES guarantee we failed the sufficient (failing to be in USA does guarantee failing to be in NYC). 😊
I don't understand the last paragraph "The only problem is that you made up your own premise B -> A. The actual premise is A -> B. You confused sufficiency for necessity."
The rest of the lesson makes sense, but I'm totally lost when I read that. Maybe make a video or remove/clarify that paragraph? I don't see what that really adds here.
@john Agreed that confused me. I think they're just saying that the conditional argument follows A--> B, xA, xB. They chose to flip it for the sake of correcting the example but it does not follow the traditional (correct) conditional argument sequence.
Valid conclusion: Only dogs play outside. Blanche plays outside. Therefore, Blanche is a dog.
Invalid conclusion: All dogs play outside. Blanche plays outside. Therefore, Blanche is a dog.
In the invalid conclusion, Blanche could be a part of another group since it does not explicitly state that you have to be a dog to play outside. She could be human, a cat, etc.
Ok so I also found this lesson confusing. What I think the key take away here is that just because the necessary condition is true tells us nothing about the sufficient condition. That's it.
My example:
All moms use the kitchen. I use the kitchen. Therefore, I am a mom
Lawgic:
Moms -> use kitchen
I KITCHEN
--
I MOM
This is Invalid. WHY? Because I'M NOT A MOM. I AM A SINGLE DUDE. Just because I am using the kitchen does that mean I am a mom? NO!
If you thought me using the kitchen meant I'm a mom you are confusing sufficiency for necessity. You are saying that using the kitchen is SUFFICENT for being a mom. you are saying "All those who use the kitchen are mom".
AFFIRMING THE NECESSARY CONDITION TELLS YOU NOTHING ABOUT THE SUFFICIENT CONDITION
All we know from the stimulus is that All moms use the kitchen.
Mom = Sufficient
Using kitchen = Necessary
If I affirm the necessary condition by saying "I use the kitchen" does that tell you anything about if I am a mom or not?
If the necessary condition is satisfied, it yields no information about the sufficient condition. The sufficient condition could be true or could be false.
@Student101 this made me giggle but also helped, thank you
@Student101 It's hard being a single mom when you're a childless, single-man. It's a struggle, fr fr
Did I get it wrong?
"All" is from group 1-necessity conditional indicators, where what follows immediately after the indicator, in this case "all", is the necessary condition. So, lawgic would be:
All Jedi use the Force.
J -> F
Dooku use force:
D -> F
Dooku is Jedi:
D -> J. This conclusion is not valid from the given premise.
In case of "only", its from group 2-sufficiency conditional indicators. What follows immediately after the indicator, "only", is the sufficient condition. So, lawgic would be:
Only Jedi use the Force.
F -> J
Dooku uses the Force.
D -> F
Chaining conditionals:
D -> F -> J
D -> J
We can infer from the above that Dooku is Jedi, which is the conclusion in the argument.
@MnM this was my writeup as well so i agree
What has made this easier for me is realizing that all is not the same as only. All refers to everything of a certain group. Only is more strict about the rules.
All dogs drink water. Other animals can drink water too.
ONLY dogs drink water. No other animals drink water.
I am also confused by this but I am a little new to studying for this oldest trick in the book that keeps kicking my butt.
All Jedi… Is that not a sufficient condition because they used “all”? All Jedi us the force so using the force is a sufficient condition of being a Jedi?
Only Jedi…is that not a necessary condition because they used “only”? While using the force is a necessary condition of being a Jedi it is not sufficient to guarantee membership in the Jedi order simply because one uses the force?
how is this any different than confusing sufficiency for necessity? I guess I don't understand why this is separate
#feedback
That last paragraph keeps tripping me up. A video would prob explain this better to avoid confusion.
@DaisyVidana Agreed.
@DaisyVidana i agree! like what does that mean "The Only problem is that you made up your own premise B->A"?!! Is that valid, or nah?
@DorinLee I think since there's an only, Jedi should be the necessary
A (Force) -> B (Jedi)
xA
-----
xB
@DorinLee Hi I don't know if this is helpful but I think by the statement "the only problem is that you made up your own premise" they mean that you alone had to assume that B-->A to make the conclusion valid. The stimulus only tells you that A--> B. The only way to make this conclusion valid is to add in this premise you made up (B--> A). So the conclusion is not valid given the premises the stimulus gives you.
SO in form it would be
A-->B
B
-------
nothing - we cannot conclude anything about A
I know this is simple but I want to make sure I am not missing it.
... did you ever hear the tragedy of Darth Plagueis the Wise?
@clickbaitcowboy It's not a story the Jedi would tell you
Keep it simple: Think about this:
Only Arabic-speakers get PhDs. Chris is an Arabic speaker. Therefore Chris gets a PhD.
If gets a PhD, then an Arabic Speaker, written
PhD->Arabic-speaker
Now here's where you don't want to mess up. It says Chris is in that "Arabic-Speaker" portion, or in other words, he's someone in the necessary condition position. But we can't work backwards. We can't say if Chris (the necessary) speaks Arabic then he gets a PhD.
It's easier to see if we use three topics, as it builds on earlier lessons:
A->B->C
We can't say "if C, then B"
Would you say this can be simplified to: "If the sufficient condition is false, the necessary condition can be true or false", and "if the necessary condition is true, the sufficient condition can be true or false"?
Correct!
you rock for this!!! Such an easy way to remember and catch a trap
can you please explain this?
@amarareid1410 thank you so much for this
I do not understand the second example. If the conditional indicator is Only, that translates to logic Uses Force --> Jedi. Since Dooku uses the force, he triggered the sufficient and is a Jedi. This is a valid logic. But why did the text say I made up my own premise? If the conditional indicator is only, I did not make anything up did I? it's very confusing.
I think they are talking about the previous example but it is very confusing nonetheless.
If it says all jedi use the force, and count doku uses the force. Its reasonable to assume that hes a jedi based on the premises. Dont understand why thats not valid
If all Jedi USE the force, that just means that all Jedi have the ability to use it. It doesn't say anything about if Sith can use it, etc. Because we just don't know if others can use it, it's not valid. Count Dooku might as well be a force user, but not a Jedi. That possibility still exists.
Another example:
All dogs like peanut butter. Jim likes peanut butter. Does this mean Jim is a dog? He might not be, right? It's not a requirement to be a dog to like peanut butter. There's a bit of a hole in that argument.
Hope this helps!
If the argument was ONLY Jedi use the force, then yes the argument would be valid. Just because All Jedi use the force doesn't mean all force-users are Jedi.
All birds eat corn. Rob eats corn. Therefore, Rob is a bird.
This is invalid because Rob could be a human, a dog, a raccoon, anything.
You explained this in a very helpful way!
This was so helpful!
Or
All chefs use knives. Bob uses a knife. Therefore, Bob is a chef.
Bob might not be. He might be a ninja or something.
@rylan.burrows06 perfect explanation