What I cannot wrap my head around is putting the examples in reverse. Making the statements sufficient.
NYC -> USA
Being in NYC is sufficient for being in the USA. I can be in Florida (currently am) and also be in the USA.
How do I do the same for the milk/store example?
Store -> Milk
It is sufficient to go to the store in order to buy milk? But, every time I go to the store, I have to buy milk; I cannot go to the store to buy bread, without having to buy milk. If I buy milk at a farm, then the necessary statement would not work, am I right?
I guess I need help with deducing store -> milk to a sufficient statement. My brain cannot make sense of it.
This will probably be explained in a future lesson I imagine, but I'd like clarification on what happens when the necessary condition is true instead of the sufficient.
I'll use the milk/store example since I think that's the one most of us are confused about. I'll also write it out to specify the premises and conclusion:
Premise 1: If I go to the store, I will buy milk.
Premise 2: I went to the store.
Conclusion: I bought milk.
And here the "Lawgic" version of Premise 1:
Store -> Milk
This might not make sense in our world, but in the world of this argument then if anyone ever goes to the store, they have to buy milk. I think this makes sense.
Now what if I change the argument to something like this:
Premise 1: If I go to the store, I will buy milk.
Premise 2: I bought milk.
Conclusion: I went to the store.
I want to say that this does not make sense/is not valid, because Premise 1 is unchanged that means that the Lawgic is still "Store -> Milk," and not "Milk -> Store." In English, this would mean that I could have gotten milk from anywhere, not just the store.
He's already using A for P and B for Q, but does anyone know if this will follow a more formal/classical logic language or a sentential logic language? Or neither and I'm just going to get really confused?
Note for anyone confused by the store and milk example:
That example is not intended to map onto whatever real life understanding you have about stores and milk. When we get a statement saying "If I go to the store, then I will buy milk," we have to analyze the meaning of that specific statement. And that statement means that if I go to the store, I am guaranteed to buy milk.
You might be thinking, "But I don't have to buy milk when I go to the store..." That may be the case in real life. But the statement "If I go to the store, then I will buy milk" does assert that I have to buy milk when I go to the store.
And, "If I go to the store, then I will buy milk" does not assert that the store is the only place that I can buy milk. It's entirely possible that whenever I visit a local farm, I buy milk. Or that I often buy milk from my neighbor. But, according to the statement, if I go to the store, I am guaranteed to buy milk.
This is why the statement is diagrammed like this:
Store → Milk
If I go to the store, the arrow points to what is guaranteed to happen: I will buy milk.
I really struggle like many in this comment list with the milk, store analogy. For me and most normal people I feel like you would identify the opposite. I would think the store would be the necessary condition because in my mind to buy milk you have to go to the store but you can go to the store without buying milk? I think im getting it more though that because the condition states if i will go to the store I will buy milk. So you know if she goes to the store she must buy milk but she can buy milk and not go to the store? someone please help me get this better
Hi! I highly recommend looking up logic symbols and connectives. They are identical to the elements we are learning, but sometimes a little bit more simplified. Ex: Sufficient condition → Necessary condition (our lesson); X → Y = If X, then Y (logic symbols); Cat → Mammal = If Cat, then Mammal.
This is not "lawgic"; it's sentential logic. Sentential logic is very helpful in philosophy when discussing the bones of argumentation. There are plenty of resources that will teach you about it without coining it as something it's not.
Questions, In my mind I am equating sufficient to subset and necessity to superset. Is that correct?
I understand a sufficient ( a cat is a mammal) relationship but I am having trouble grasping the necessity relationship ( a mammal does not mean it's a cat).
I am having a hard time understanding why the arrow points from subset to superset and not the other way around? When I visualize and read these statement my mind first goes to the big picture (superset) and then to the subset. Can anyone help me find a way to understand it better? #help
I like how this lesson includes an alternative way of thinking of sufficient and necessary conditions as subset and superset -- this is a very important key that can easily allow arguments to be drawn out in sets (aka circles :) )
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73 comments
I am excited to learn 'lawgic' as I think this will be really helpful for breaking down questions quickly! :)
Can we not put "going to the store" as a superset and "buying milk" as a subset? It is sufficient for you to go to the store to buy milk.
I think one way to understand the arrow, is that the arrow always points in the direction of certainty.
If I go to the store, I (must) buy milk).
Go to store -> buy milk.
Whereas you cannot say:
buy milk -> go to store. What if I got milk elsewhere?
What I cannot wrap my head around is putting the examples in reverse. Making the statements sufficient.
NYC -> USA
Being in NYC is sufficient for being in the USA. I can be in Florida (currently am) and also be in the USA.
How do I do the same for the milk/store example?
Store -> Milk
It is sufficient to go to the store in order to buy milk? But, every time I go to the store, I have to buy milk; I cannot go to the store to buy bread, without having to buy milk. If I buy milk at a farm, then the necessary statement would not work, am I right?
I guess I need help with deducing store -> milk to a sufficient statement. My brain cannot make sense of it.
This will probably be explained in a future lesson I imagine, but I'd like clarification on what happens when the necessary condition is true instead of the sufficient.
I'll use the milk/store example since I think that's the one most of us are confused about. I'll also write it out to specify the premises and conclusion:
Premise 1: If I go to the store, I will buy milk.
Premise 2: I went to the store.
Conclusion: I bought milk.
And here the "Lawgic" version of Premise 1:
Store -> Milk
This might not make sense in our world, but in the world of this argument then if anyone ever goes to the store, they have to buy milk. I think this makes sense.
Now what if I change the argument to something like this:
Premise 1: If I go to the store, I will buy milk.
Premise 2: I bought milk.
Conclusion: I went to the store.
I want to say that this does not make sense/is not valid, because Premise 1 is unchanged that means that the Lawgic is still "Store -> Milk," and not "Milk -> Store." In English, this would mean that I could have gotten milk from anywhere, not just the store.
He's already using A for P and B for Q, but does anyone know if this will follow a more formal/classical logic language or a sentential logic language? Or neither and I'm just going to get really confused?
Note for anyone confused by the store and milk example:
That example is not intended to map onto whatever real life understanding you have about stores and milk. When we get a statement saying "If I go to the store, then I will buy milk," we have to analyze the meaning of that specific statement. And that statement means that if I go to the store, I am guaranteed to buy milk.
You might be thinking, "But I don't have to buy milk when I go to the store..." That may be the case in real life. But the statement "If I go to the store, then I will buy milk" does assert that I have to buy milk when I go to the store.
And, "If I go to the store, then I will buy milk" does not assert that the store is the only place that I can buy milk. It's entirely possible that whenever I visit a local farm, I buy milk. Or that I often buy milk from my neighbor. But, according to the statement, if I go to the store, I am guaranteed to buy milk.
This is why the statement is diagrammed like this:
Store → Milk
If I go to the store, the arrow points to what is guaranteed to happen: I will buy milk.
This example doesn't make sense to me. This is what makes sense to me:
Store -> Milk
Mammal -> Cat
you have to go to the store to buy milk, but you dont have to buy milk if you go to the store.
just like how you have to be a mammal if you're a cat, but you dont have to be a cat if you are a mammal.
reading the comments below to look for some extra clarification but I see everyone seems lost as well.
If you get confused which goes at what side of the arrow, I remember it by "Start with Sufficient, Next is Necessary." S -> N
so if A then B.
A has to happen for B to happen
sufficient condition → necessary condition
I really struggle like many in this comment list with the milk, store analogy. For me and most normal people I feel like you would identify the opposite. I would think the store would be the necessary condition because in my mind to buy milk you have to go to the store but you can go to the store without buying milk? I think im getting it more though that because the condition states if i will go to the store I will buy milk. So you know if she goes to the store she must buy milk but she can buy milk and not go to the store? someone please help me get this better
So if this argument was given it would be wrong:
*If I go to the store then I buy milk.
I bought milk
I went to the store*
because I could have bought milk elsewhere besides the store?
Hi! I highly recommend looking up logic symbols and connectives. They are identical to the elements we are learning, but sometimes a little bit more simplified. Ex: Sufficient condition → Necessary condition (our lesson); X → Y = If X, then Y (logic symbols); Cat → Mammal = If Cat, then Mammal.
"If you don't like it, sue me. But first, you have to take the LSAT and get into law school so pay attention." that was unannounced lol
Quick question in reference to the following:
store → milk
[sufficient condition] → [necessary condition]
So why would store be the sufficient thing in relation to milk and not the other way around?
This is not "lawgic"; it's sentential logic. Sentential logic is very helpful in philosophy when discussing the bones of argumentation. There are plenty of resources that will teach you about it without coining it as something it's not.
why is there a store → milk in the sufficient → necessary condition?
What is it trying to say lol.
SUBSET -> SUPERSET
SUFFICIENT -> NECESSARY
Questions, In my mind I am equating sufficient to subset and necessity to superset. Is that correct?
I understand a sufficient ( a cat is a mammal) relationship but I am having trouble grasping the necessity relationship ( a mammal does not mean it's a cat).
Why does sufficient always lead to necessary?
I am having a hard time understanding why the arrow points from subset to superset and not the other way around? When I visualize and read these statement my mind first goes to the big picture (superset) and then to the subset. Can anyone help me find a way to understand it better? #help
"store → milk"
what is this trying to say lol
#help (Added by Admin)
This has been the most helpful part for me so far. That just finally clicked for me!
I like how this lesson includes an alternative way of thinking of sufficient and necessary conditions as subset and superset -- this is a very important key that can easily allow arguments to be drawn out in sets (aka circles :) )