Existential Import: Aristotelian v. Boolean Perspectives

[@erinshults2184]

This is very clarifying. Thank you so much for making this!!

[@FlumdogMillionaire]

Glad it was helpful!

[@daleputnam8300]

Thank you for making this, it was helpful.

[@themadmanchannel9036]

Thank you for this lucid explanatory video.

[@FlumdogMillionaire]

You are welcome!

[@joebuck4496]

So basically here’s the thing about Logic…when people apply Aristotelian Logical rules to Logic they do so consistently across the board. But when people “Claim to” apply Boolean Logical rules to Logic they inconsistently do so. Why does Boole tell us that universal and particular statements exclude each other, YET people who claim to apply Boolean Logic still follow the Aristotelian guidelines that subcontraries can not both be false?? Both CAN be false according to Boole’s distinction.

[@ZishanWazedBegg]

Awesome. Very clarifying. Thank you

[@derumweger1590]

Logic's subject matter is really about essence not existence. So much of the Existential Import chimera is missing the point. I would argue that modern Booleans are not doing logic at all. Booleans have confused existence with essence.

[@oblamovadvanced5956]

Agree.Avicenna says the same.

[@clarkharney8805]

Absolutely ! Essence is what“ness”, what makes something what it is. Esse is the is; aka existence

[@justingrove5190]

Thank you sir well made

[@ruthabiti5219]

Best explanation 👏👏👏👏

[@tupacshakur8286]

The best

[@tobiayo4930]

If an endangered specie gets extinct does it fall under the aristotelian category like the dragons?

[@derumweger1590]

What facts of reality lead to conclude the necessity of existential import? I argue logic is not about existence as such, but about existence as known, subject to prior laws of thought like supposition. This presentation confuses the subject matter of logic as the science of things as known with the science of things as they are, given in the first act of the mind or apprehension.

[@FlumdogMillionaire]

Thanks for the comment! This is a short video meant to explain the difference between Boolean and Aristotelian approaches to existential import for my introductory logic students. Unfortunately, there's just not enough time to get into anything else!

[@derumweger1590]

​@@FlumdogMillionaire The video's title is appropriate. These are perspectives. But, I must point out that there is no such thing as Aristotelian logic (my preference) and Boolean Logic. Such terminology serves only to confuse the subject, truth in identification. Truth must be demonstrated, whichever the method.

[@ceryx6849]

I wonder if there’s an ontological reason for the difference you exposed or if it is completely arbitrary and we’re about ground heuristics of their respective logics here. I think you kinda discussed it with someone else in the comments. The point was that existential imports into universal propositions lead to absurd logics (like with the box). But I’m still feeling dizzy about it because I can find many cases where it doesn’t lead to absurdities and almost no case where it does. Maybe it doesn’t when we talk about simple reasonings, and it begins to create absurdities only when it becomes complex like with the box.

[@ipenchimphapaellium7683]

thanks

[@Zen-lz1hc]

"Some dragons are fire breading monsters" -Commits to the existence of at least one dragon is a fire breading monster. WAIT WHAT??? THAT CAN'T BE RIGHT! LAST TIME WHEN I CHECKED DRAGONS DO NOT EXIST.

[@zb3301]

What books would you consider to be good primers for boolean logic? I study aristotelian logic in Arabic through classical texts and would like to do a side by side comparison after organizing modern logic in the same structure as these aristotelian texts.

[@FlumdogMillionaire]

Thanks for watching! I'm following Hurley's Concise Introduction to Logic 13th edition. He's got a nice explanation. Here's a link to an article with a nice bibliography: www.logicmuseum.com/wiki/Existential_import

[@dasemaw1862]

What about " some dragons breath fire" They both agree an i statement make an existintial import but what is the logic in that since There isn't such thing as dragon in reality?

[@1Spacecore]

That would still be an existential fallacy. The class "dragons" does not have any members, so it does not exist.

[@matematikemulo]

But why Boole changed the meaning of "all" excluding existential import? And altering the more common and natural meaning of "all" in languages? (btw thanks for the interesting video :-))

[@FlumdogMillionaire]

I don't think he was changing the definition of "all". I think at least one thing he was thinking of what "All S are P" actually means. To Boole, this means that 'no members of S exist outside of the P category'. Note that this statement doesn't affirm the existence of any S's - it only affirms that there are none in the P category. Here's an example: I can say "All of the unicorns are magical horses with one horn," without making any claim about unicorns actually existing.

[@matematikemulo]

@@FlumdogMillionaire thank you for your prompt answer! Exactly, to Boole it means that, but to most of the rest of the world (ancient logic and most of everyday logic) it meant and means something different (it implies existential import). So in this sense he changed the meaning of an existing word. Why?

[@FlumdogMillionaire]

@@matematikemulo I did a bit more digging and here's what I found: The idea that all universal propositions lack existential import is not Boole's idea; it was John Venn's in his book Symbolic Logic. Venn thought that allowing all universal propositions to have existential import leads to logical absurdities. Venn's book was published in 1881, you should be able to find it online for free.

[@matematikemulo]

@@FlumdogMillionaire thanks! I read some more sources about Venn, particularly Wu's article projecteuclid.org/download/pdf_1/euclid.ndjfl/1093893792 But I still don't see the answer. Let's define I = some S are P, B = no S is not P and A = all S are P. In ancient logic A = I∧B. In everyday logic this is the standard interpretation of A if we talk about past verifiable events. Venn says : in some much rarer cases (laws of science or right, such as "all thieves will be punished") we don't know if I is true (we don't know if there will be some thieves), so let's change the definition of A, so that A = B. But in laws you are talking about future or universal hypotheses, so you cannot affirm neither the existence nor the non-existence, it is simply undefined. So you don't know whether statement I will be true, but you dont know either whether B will be true. There is an implicit conditional statement: if S exists, then A=I∧B. If you need to say B, you can just say B. So where is the need to change the definition of A?

[@siktasimantini1440]

Some cenatures are vindictive. Does this proposition has existenial import

[@spotify_ERROR404]

nat atbot GPT-3 [:|]... 11:41 "thank you. " [BEEP]