CRITICAL THINKING - Fundamentals: Validity [HD] 

shout out to all my fellow university students trying to get by in there philosophy course

If you want to think more abstractly about these types of problems without having to replace things with letters or choose new items that make the premises true, here's an interesting approach that thinks of the items as boxes being placed into other boxes. This works because putting things in boxes allows us to imagine items in physical positions, making their relationships to each other in space clear. *Original* All fruit is a chair. Square is a chair. Conclusion: Square is a fruit. *Box Translation* The fruit box is in the chair box. The square is in the chair box. Conclusion: Is the square in the fruit box? Answer: No, as far as we know, we only put the square in the chair box. Premises tell you to take an item and put it in a box. Conclusions are yes or no questions about which box an item is in. For a comparison, look at this valid version of the argument: *Valid version* All fruit is a chair. Square is a fruit. Conclusion: Square is a chair. *Box Translation* The fruit box is in the chair box. The square is in the fruit box. Conclusion: Is the square also in the chair box? Answer: Yes, since the square is in the fruit box and the fruit box is in the chair box, the square has to also be in the chair box.

this is so hard!!! i have to know this for class and once i start feeling like i finally understand i get hit with a question and everything i thought i knew goes out the trash.

The last argument is invalid. Truth of C1 doesn't necessarily follow from the truth of both P1 and P2 (for example if both fruit and chair were both non-overlapping subsets of chair). However changing the second premise to "A square is a fruit" would make this into a valid argument.

Invalid. All fruit may be a chair, but vegetable may be a chair as well. Square could be vegetable.

It becomes borderline impossible for me to understand what's going on when they throw out nonsense phrases like "all fruit is a chair"

invalid because all fruit may be chairs, but not all chairs might be fruit. if you say "Square is a fruit" and "Therefore, Square is a chair", that would be valid.

Had an assignment for my ethics class and this helped so much. I was struggling for an hour until I found this video. Thank you!

Invalid. It's easier to see with term substitution where the premises are accepted to be true: All Lamborghini Countachs are cars. A Honda Civic is a car. Therefore, a Honda Civic is a Lamborghini Countach. All citrus fruits are acidic. An orange is acidic. Therefore, an orange is a citrus fruit. All architects are people. A landlord is a person. Therefore, a landlord is an architect. All three examples follow the same form of argument, but one example arrives at a false conclusion, one a true conclusion, and the last at a contingient conclusion. In an invalid argument, the truth of the premises does not *guarantee* the truth of the conclusion. As it so happens, inductive arguments, the mainstay of science, are invalid arguments.

Valid: A is B (coffee is a bean) B is C (bean is a food) Therefore A is C (coffee is a food) Invalid: A has B (dogs have fur) C has B (Claire has fur) Therefore C is A (Claire is a dog)

Correct me if I'm wrong and you might have to draw this out... In a Venn Diagram the large rectangle would be labeled chair. Within the large rectangle would be a circle named fruit since "all fruit is a chair". Then the X mark representing square would be on the border of the circle named fruit due to the second statement not saying explicitly if square is or isn't a fruit. So there's a possibility that square is something other than a fruit making the argument invalid.

Thankyou, I feel a lot clearer on this however I still feel like I haven't fully grasped the concept of validity in philosophy.

This makes sense intuitively, but I'm interested to know more about exactly how an argument is determined to be valid. What is the method for determining if an inference follows from the premises?

what the heck? he didn't give the answer at the end of the video!

In programming we use something similar to this called inheritance. Saying all Fruit is a Chair is like saying Fruit is a child of chair. This relationship is one way, Chair could have multiple children but Fruit can only have one parent. Therefore if Square is a Chair then it could be a Fruit. If Square was defined as a Fruit then it must also be a Chair.

What about this argument: P1: LA county requires a vaccine mandate to enter stores. P2: Vaccine mandates are discriminatory C: Therefore, LA county is discriminatory.

Im trynna getting this philosophy course so that i can enhance my arguments skills, that can be necessarily used in law school.

This was so clear to me, thanks for the video. I understand now.

"Metaphysics As A Guide to Morals" by Iris Murdoch is a must read!

They could have explained the concept much better. I will try to summarize the video in simple terms. 1) An argument is a list of statements that support a conclusion or answer a question. 2) A statement, in an argument, is known as a premise. 3) A valid argument is an argument in which all of the premises agree with each other, assuming that the premises are true. In other words, it’s valid when the premises do not conflict nor contradict the each other and we say the premises are true. 4) A valid argument does not identify if the argument is true or false, rather a valid argument only identifies if the premises support the conclusion or not. Example 1: P1: Bobby eats all foods that are red. P2: Bananas are red. Conclusion: Bobby eats bananas. In Example 1, the argument is valid but not true because P2 is not true, yet all of the premises agree if we assume P2 is true. Example 2: Question: Is the world round? P1: Bobby says the world is flat. P2: Bobby is always right. P3: The world has been proven to be round. Answer: Yes, the world is round. In Example 2, the argument is not valid yet true because the world is round but the premises don’t agree. We can use valid arguments to find the best answer when our known information is incorrect or limited. We can then find better answers to our questions using another valid argument as we learn the correct or new information. That’s why we should be humble and unbothered when someone criticizes our ideas and actions. What you think you know might be valid but not correct nor true. Great video thank you!

I was a mathematics major and for some reason this confused the heck out of me. Not sure if it was because I have a background in logic or just the way it was explained?

Will Smith, will smith I will smith Therefor I am Will Smith

Would this argument be valid: P1: A company mandating vaccination for its employees is involved in discrimination P2: Google is mandating the COVID vaccine for its employees. C: Therefore, Google is discriminating based on vaccination status.

The last argument is invalid, because: P1: All X (fruit) is a Y (chair) P2: Z (Square) is a Y (chair) it said all X is Y, not all Y is X, thus you cannot say Z is X because of it being Y, as Y doesn't mean X, this could be true if we made 1 more premise to the argument P3: All Y is a X, then the argument would be valid, but as it stands, it's invalid.

In the example at the end, the premise both p1 and p2 are true, but the conclusion is invalid, as square is not a fruit.

a conclusion being necessary means that the claim also conclusion is needed. think of it as applying for aa job and the interviewer says that you are necessary fir the job. you are needed because of your qualifications. inferencing here means to use the evidence being the premises and using them as reasons to make your claim. youre conclusion is what you strongly believe in and the premises are the because, they let us know why you think that. you could also work backwards by giving the claim 1st nd then using the premises to make convince us of what you claim. this happens only in valid deductions, the conclusion is based off of the premises.

Someone tell me if this is a reasonable thing to do: The final argument can be simplified by replacing some of the words with variables? If fruit=A and chair=B and square=C then the argument goes p1. All A are B p2. C is a B c1. therefore, C is an A That seems like an invalid argument. Is there any flaw in what I did here?

If all fruit is a chair, and square is a chair, then square must be a fruit. If P1 was true and P2 is true, the validity of the Conclusion resides on if it is true, making the argument valid, or untrue, making the argument invalid. Review the video @ 4:05. False premises can produce a valid argument. If we use our conventional understanding on what distinguishes a fruit from a chair, then P1 would be classified as a false statement along with P2 based on the same principal between a square and a chair. However, if P1 and P2, even though we know the statements to be false, were in fact true, using a more ambiguous definition of the objects, the conclusion would in turn constitute as also being true. So in conclusion, the statement is VALID. (capitalized for visual effect, I am in no way yelling at you)

Looking at his Example: 1 All aliens speak english 2 (name) speaks english C therefore (name) must be an Alien is a Valid statement Wouldn't the question at the end be a valid argument too? I might be wrong af tho lol

Why you give examples of not true things as valid arguments premesises what point am i missing there?

Invalid, two objects that share one property doesn't make them identical as the property is not defined as property describing all properties of the object.

If we were to substitute 'the chair' for 'a chair' in P1 and P2, would this then become a valid argument?

Are whiteboard animation videos still valid?

Your explanation is satisfy... do updated me in your next up coming videos.. thank you Sir. From N.E India

i Really do not get that immortal part. How is all humans immortal??

a splif is a splat if a fruit is a splif than a splaf is a sploof am i wrong?

Invalid. It could be valid if P2 was “Square is a fruit” and the conclusion was “therefore square is a chair.” In order for the original argument to be valid we would need a premise that chairs can only be fruit and nothing else.

HUGE HUGE HUGE fan of yours. PLEASE never stop doing videos. There is a type of fallacy im hearing theists accuse me of. Can you help me with it? (Or someone else familiar with logical fallacies?)

how about the statements Aliens speak English Splot is alien Therefore, Splot speaks English It is confirmed valid but Americans also speak English? Must be invalid or i just dont get it?

@4:08 it is said that this is an argument with all false premises in it - but how is premise 2 ("Iris Murdoch is a human.") false? Is Iris Murdoch not a human?? (..obviously we know Iris Murdoch is a human)

how does validity of an argument define?

Where my Night Owls at? 🦉

Paul, could you please explain how the validity is affected if it is a compound syllogism and one or more premisses are analytic propositions: eg. P1: All symbols are made by minds (analytic premise) , P2: All codes are made of symbols (analytic), P3: Therefore, all codes are made by minds, P4: ASCII is a code, Conclusion: Therefore, ASCII was made by a mind. Is P3 also an analytic proposition because it follow from 2 analytic propositions? By "analytic" I mean necessarily true, as apposed to "synthetic" propositions whose truth depends on evidence.

How are the people in the opening statement not using validity in the same sense? An argument is taking place and they are making a statement that "oh aha! you have finely made a valid argument that follows logical rules instead of fallacies and nonsense." They are using validity in the philosophical sense. They are not stating agreement with the argument just accepting that the person they are debating has finally formed a valid argument.

So how do we determine if a premise is true?

Quality content I need on youtube

4:08 You said all the premises would be false, but P2 is true (or at least it was earlier).

Note : The statement : All humans are mortal is a conditional statement. It should properly be framed as : All humans are mortal, so far.

not valid. If P2 was 'Square is a fruit', and C was 'therefore square is a chair' then that would be a valid argument. But just because all fruit is a chair (a slightly dubious statement because of the grammar in my opinion,) that doesn't give us any information about square. Square may be, or may not be. We don't know.

thank you so much for helping students like me

Invalid. All fruits are chairs does not mean all chairs are necessarily fruit.

Response to the last question: Invalid. Association fallacy.

P1 tells us that all fruits are chairs, not that all chairs are fruits. As such, p2 cannot prove the conclusion as it only tells us square is a chair, not specifically a fruit. So it's invalid.

when someone asks you if it makes sense, implying that's true, and you're like...

The last argument is invalid. If all fruit are chair, and the square is chair, there is a possibility that square may not be fruit, even though it is chair.

Of course, fruit cannot be a chair and a square is not a chair, we know this. However, if without a doubt the statement is ensuring all fruit is a chair then there is absolutely no way a triangle can be a chair (the premise specifically stated that a fruit is a chair) or that pizza can be a chair ( the premise specifically stated that a fruit is a chair). Given this information, the conclusion is a valid deductive argument because of the specific premise and conclusion. The question was "is the argument a valid deductive argument or an invalid deductive argument NOT if the argument was concluded by SOUND statements. Right? Wireless Philosophy

buenas noches sería posible incluir subtitulos en español gracias

P1, Whatever begins to exist, has a cause of its beginning. P2, The universe began to exist. C, Therefore, the universe has a cause of its beginning.

Good explanation👋!

To the ones that are scrambling their brains ... The answer at the end is that the conclusion does not add up logically. You can see it's invalid by breaking the pattern when u think in terms of logic (Although Im not sure it's the right way to interpret it) But yeah, logic..

Why in all the youtube of this types the examples of untrue valid arguments are nonsensical. It makes it difficult to grasp the concept when there are obvious absurdities. Is there no philosopher that can come up with an untrue valid argument that is non-nonsensical?

I don't understand the final example, maybe I'm using too much logic. for me a chair is not a fruit and vice versa so the example is not valid because it's simply illogical to think a chair is a fruit or a fruit is a chair. I don't even understand why it is used an example it's just non sense. Maybe the example should have been tomatoes are fruits, fruits are good for health therefore eating tomatoes is good for health. All premises are true so valid and conclusion is good too. Why does it has to be all confusing and shakesperean and who the hell reasons like this in our modern world?

Last argument is invalid. The truth of the premises are not relevant to the conclusion.

So logic assesses the validity of an argument and prior knowledge assesses the truth of it's premises... So one must use both logic and prior knowledge to assess the truth of a conclusion. Okay, okay I think I get it

Way better than my professor

Invalid.

Of course, fruit cannot be a chair and a square is not a chair, we know this. However, if without a doubt the statement is ensuring all fruit is a chair and a square is a chair then there is absolutely no way a triangle and be a chair (the premise specifically stated a square) or that pizza can be a fruit (the premise specifically stated that a fruit is a chair). Given this information, the argument is a valid deductive argument because of the specific premises and conclusion. The question was "is the argument a valid deductive or an invalid deductive argument" NOT if the premises or the conclusion were SOUND statements.

Invalid. We don't know if all chairs are fruit. Square could be a fruit, which makes it a strong inductive argument, but not a valid deductive argument.

Nice video and helpful!

the split and splat thing sound a lot like Hegel's philosophy...

invalid, because the conclusion is false? cmiiw

It is a Valid Argument.

thank you sir

Invalid, and thank you a hundred times.

Great video Paul!

Urgh, surely this could have been explained better through the introduction of simple syllogisms? Or is the idea that the audience is afraid of algebra? Saying there are formal structures in which A is B; B is C; so A is C actually provides a basis for understanding the relationship between different statements through variables and functions, whereas repeating the 'If the premises are true the conclusion must be true' thing five times doesn't explain 'why' validity works at all.

I dont understand All men are mortal Socrates is a man Therefore, Socrates is mortal All dogs have fur Claire has alot of fur Therefore, claire is a dog. they both look the same to me even though the last arguement is invalid???

Invalid argument at the end, if all chairs were fruit it would be valid, but since all fruit are chairs, and square is a chair, the argument cannot logically conclude that.

thanks this video is so amazing

It's invalid. you must establish what Square is part of. Is it part of the larger or the smaller population. With "all fruit" being the larger population than "a chair", and "square" being part of the smaller population "chair", you cannot infer from the small population to the larger population. Therefore, invalid.

INVALID Premises are TRUE Conclusion is FALSE (Square may not be fruit)

Invalid be cause all fruits are a chair but some chairs could be fruits. Therefore chairs are chairs.

valid

And this is the fundamentals behind the majority of theoretical physics.

Wtf? Where's the answer?? I need someone to valid(ate) me!

even though all fruits may be a chair, not all chairs are fruits

math! If a = b and b = c, then a =c. If a = b, but b does not equal c, then a cannot equal c. :)

Invalid. Typical example of affirming the consequent.

What I'm taking away from this is someone could have a totally valid argument, but it also be totally bullshit.

Oh! I know this one! Invalid! This is the fallacy of affirming the consequent or fallacy of the converse, if you will! :D

Invalid because the conclusion is false. It would be valid if,the premises(P2) was square is a fruit. Then It conclusion was therefore, square is a chair.

I love this video

Premises is plural.

Invalid? Maybe valid if P1 was changed all chair are fruit

U save my life 🙏

Spliff is a splaff. Wtf! Clear simple wording or easier contexta would make a huge difference to landing this video.

the last one is definitely invalid

Who is to say a pencil can't be a chair too even though it is not a fruit which is always a chair? A square is a chair even though it may not be a fruit. But all fruit is a chair.

Thank you

invalid because fruits may not be the only thngs that can be chairs