i dont know how to thank u..this whole series of videos are really helpful..u teach in such a way that complex things look simple and i m really enjoying solving logic problem....keep up the good work mate..thank u so much man..
I wish you were my teacher :( My teacher can't even solve his own quiz problems that he gives to us. These youtube videos have helped and TAUGHT me so much for my online class. My own online teacher taught me nothing.
“We can speak and think only of what exists. And what exists is uncreated and imperishable for it is whole and unchanging and complete. It was not or nor shall be different since it is now, all at once, one and continuous.” ― Parmenides
Professor Thorsby, At 5:04, you say that we are allowed to apply an existential generalization onto a statement function, not only a statement name. Doesn't this allow us to exploit universals in such a way as to commit the existential fallacy? Or does the existential fallacy not apply in first-order logic? I'm a little confused. For example: 1. (∀x)(Cx > Dx) 2. Cx > Dx ||| 1, UI 3. (∃x)(Cx > Dx) ||| 2, EG Thanks a lot for all of your great videos! Logic is one of my favorite courses now.
I find a god way to remember the change of quantifier rules is this, since it limits it to two statements of equivalence, and applies to either quantifier: 1) Positive quantifier and positive function= negative inverse quantifier and negative function. 2) Negative quantifier and and positive function= positive inverse quantifier and negative function.
Hi Professor Thorsby, I got some doubts, which I need to trouble you for. [1] For UI, why is there a need to perform EI first? I hear that the existence of the variable a is required for UI to proceed. [2] For simplification, why is there a need to commutate first? e.g. Ra · ~Qa, then ~Qa·Ra , Kind regards.
I don't know if you read this comment but you must know that this Videos are much better than my Elementary logic classes. Thank you ;)
i dont know how to thank u..this whole series of videos are really helpful..u teach in such a way that complex things look simple and i m really enjoying solving logic problem....keep up the good work mate..thank u so much man..
I wish you were my teacher :( My teacher can't even solve his own quiz problems that he gives to us. These youtube videos have helped and TAUGHT me so much for my online class. My own online teacher taught me nothing.
thank you SO much for this. i wish i'd seen your videos months ago, instead of tonight as i'm studying for my introductory logic final!
I read the book, pause listen to lecture , then finish the Chapter
you are setting the example!
thank you again
“We can speak and think only of what exists. And what exists is uncreated and imperishable for it is whole and unchanging and complete. It was not or nor shall be different since it is now, all at once, one and continuous.”
― Parmenides
Professor Thorsby,
At 5:04, you say that we are allowed to apply an existential generalization onto a statement function, not only a statement name. Doesn't this allow us to exploit universals in such a way as to commit the existential fallacy? Or does the existential fallacy not apply in first-order logic? I'm a little confused.
For example:
1. (∀x)(Cx > Dx)
2. Cx > Dx ||| 1, UI
3. (∃x)(Cx > Dx) ||| 2, EG
Thanks a lot for all of your great videos! Logic is one of my favorite courses now.
I find a god way to remember the change of quantifier rules is this, since it limits it to two statements of equivalence, and applies to either quantifier:
1) Positive quantifier and positive function= negative inverse quantifier and negative function.
2) Negative quantifier and and positive function= positive inverse quantifier and negative function.
Does anyone have a resource or a hint for finding the solution on 8.3, Part 1 #14 ???? Stumped in Sacramento...
Hi Professor Thorsby, I got some doubts, which I need to trouble you for. [1] For UI, why is there a need to perform EI first? I hear that the existence of the variable a is required for UI to proceed. [2] For simplification, why is there a need to commutate first? e.g. Ra · ~Qa, then ~Qa·Ra , Kind regards.
Oh, Hi Mark!
[3] Hi Professor, is it possible to apply change of quantifier to "[Ǝx]~Ax v [Ǝx]~Bx" to "~[x]Ax v ~[x]Bx"?
Like :)
Lines 3 to 4 do not logically follow. Just because there exists something which is not an L, it does not follow that nothing is an L.