Determining Validity of an Argument Using a Truth Table

In this video we look at using truth tables to determine whether an argument is valid or a fallacy. Four common valid forms are presented and four common invalid arguments (fallacies) are presented.

[@dustyg4261]

This was extremely helpful; i was so stuck after listening to my college lecture. You broke it down better than my professor, so thank you

[@Mudkip2701]

my math book didn’t explain how to get the conclusion, but this cleared it up for me, thank you so much!

[@yasminahmed3495]

Agreeeee

[@emmanueltuyishimire8234]

I'm Rwandan and I feel hy of this video so thank you

[@pratibhasingh750]

great video very helpful thank you so so much I have an exam after some days and I was very confused but because of this video my all confusion related to this topic get sorted😊

[@chasitychristian9696]

Thank you very much for making this video. I was stumped!!! This video just made it CLICK!!!

[@happysunflower3929]

This video was really helpful .Thank youuuu

[@faridamohamad1019]

👏👏so useful

[@SynenSimene]

You help me a lot. THANKS.

[@kevinconnelly6770]

Great video, very helpful.

[@tristansamontina4949]

How about: •Your are taking at least 12 credits or you are a part time student. •if you are taking at least 12 credits, then you are matriculated. You are not a part time student •therefore, you are matriculated. Can I ask something sir, what is the meaning of r in this topic

[@csvaughen]

that's a good one, you could choose any statement in that argument to be p, q or r... suppose you choose this way: p=you are taking at least 12 credits, q=you are a part-time student, r=you are matriculated then you could write the argument in symbolic form as: p v q p ->r ~q --------- r And creating the truth table for this one would be bigger, not only because there are three premises, but because there are 3 variables, so the table has 8 rows to account for the 8 possible variations of true or false for each of the 3 variables

[@asmaulhusna1680]

Thank you so so so much!!!!!!

[@malatmengesha8344]

it is helpful video ,thank you so much!!!

[@gsibuma1128]

This is the argument that I need to answer: Consider the statement, “If you pass the UPCAT, I’ll buy you a car.” If you took the UPCAT and I bought you a car, can you conclude that you passed the UPCAT? That has the same form as the example 1 in the video. So the statement is not always true and it is an invalid argument. How can I answer the question tho?

[@csvaughen]

Take the statement "If you pass the UPCAT, I'll buy you a car." That alone is just a statement, not an argument. I assume an argument requires at least two premises. Now you continue, "if you took the UPCAT and I bought you a car", you said "you took it" but didn't indicate passing or not. So let's say you have this argument: Premise1: If you take the UPCAT, then I'll buy you a car. Premise2: I bought you a car. based on those two premises, the conclusion "You passed the UPCAT" is not valid. You could not logically make that conclusion.

[@lupitatalksalot]

thank you!!!

[@khreszmaerafer4035]

It is a very helpful video but i'm confuse in last example. The form is not written from valid nor invalid forms. So I did a truth table and got T,T,F,F for last column. It is invalid right? Or I made a mistake?

[@csvaughen]

hmm, example 8? that one's valid, the truth table should work out true in every case

[@rhiannelopez7987]

Thank youu so much!!!

[@michalchik]

This is good, but wouldn't 8 variables be 2 to the 8 or 256 instead of 8!?

[@thedestroyer9423]

so good

[@cyberNva]

I don't understand why the first ex is invalid ??

[@csvaughen]

First example is the fallacy of the converse. If p->q is true, that doesn't mean q->p is true.

[@baffoeagyei1501]

it is supposed to be valid not invalid so i think he can correct it

[@marooqi]

I thought the and symbol is a dot. what am I thinking about?

[@csvaughen]

there are multiple different notations... dot is common and makes sense, and has properties similar to multiplication en.wikipedia.org/wiki/Logical_conjunction

[@АлинаКусаинова-ц1ь]

hi you made a mistake in the second argument in 4th column, the third column implies to first column equals , second line F implies to T is T not F in this case argument become ivalid check everything.

[@csvaughen]

Hi, I checked example 2 again and it is correct, the 4th column is a conjunction, not an implication (as you suggest), so it is correct in the video, final conclusion is also correct, thanks for your feedback though

[@aivepulvera7025]

hi @@csvaughen , you are right..even if I negate the q statement because of the word `not`, still the answer is valid.

[@saraguerrero2432]

P P>Q (P^Q)>R -S > -R Conclusión S Can someone help?

[@csvaughen]

try this website web.stanford.edu/class/cs103/tools/truth-table-tool/ I just entered that argument above as a single statement in the general form (A->B) where is all of the first 4 lines you have connection with "and", B is just the variable S as to determine whether this is a valid argument. It came back as always true with this calculator (very tedious to do by hand since you have 4 variables that is 16 rows)

[@triciadawn]

thank you!!!!