Thanks for making these videos! They're are easier to understand than every other resource on modal logic I've found. There is one thing I don't get about the semantics of quantifier operators though. The way I understand the existential operator is as referring to existence in a platonic sense, like when we one says "for every prime there exists a larger prime". It seems to me like a weird choice of semantics to understand existence as physical existence. It also seems to make the system less expressive, because there is no way to express existence in every possible world, while the converse is true: if existence means existence in every possible world, I can always define a function F(w, x) as true if x physically exists in world w, and then instead of saying "∀x P, w" I can say "∀x F(w, x) → P, w". This would also make the paradox you mention not a paradox anymore since whenever something exists, it would exist in every possible world, which is what one would expect of abstract entities like numbers. So why is it that the existential quantifier is understood as ranging over the set of things that exist in the one possible world only, and are there any alternative interpretations I could look into? Thanks!
@GFumet3 жыл бұрын
Amazing video! I've never seen this problem explained so simply and elegantly. A great resource!
@AtticPhilosophy3 жыл бұрын
Thanks! I've taught it for several years, I guess that helps getting it clear
@frankavocado Жыл бұрын
The thin concept of existence may handle the 'non-actual' well, but how does it account for the genuinely substantive - i.e. the notion of 'things' from which everything is composed? Granted, in modern physics, there is a case for only relations and not actual bits of stuff . But how, under the 'thin' account, do we capture, logically, the notion of absolute things? I guess we just kind of posit them? Maybe as a general case or a theory or special modifier? - anyway, this is all fascinating stuff!
@AtticPhilosophy Жыл бұрын
Well, real physical objects would exist in the full, *thick* sense, whereas only those difficult entities - the merely possible, maybe the fictional entities, maybe the abstract ones - would exist only in the *thin* sense.
@frankavocado Жыл бұрын
@@AtticPhilosophy Thanks! So, two categories of existence, maybe more? Philosophical richness, indeed.
@GCBrin3 жыл бұрын
Hi! Loving the videos, thanks so much for making them :) Was curious whether you'll do one on two-dimensional semantics and issues surrounding it?
@AtticPhilosophy3 жыл бұрын
Great suggestion! Thats quite an advanced topic & I've never worked out what's the simplest way to present it, but I'll give it a go
@poklar10 ай бұрын
Any chance you’d consider making a video about Free Logic? May be a useful complement to this and related videos?
@AtticPhilosophy10 ай бұрын
Great idea! That's definitely something I should cover soon.
@puilamwu2 жыл бұрын
Thank you so much for making this kind of videos. I find the idea of thick and thin existence really interesting. Are there any books, articles or works of particular philosophers that I can read further if I want to dig deeper on this idea? Thanks a lot!
@AtticPhilosophy2 жыл бұрын
Graham Priest’s book, Towards Non-Being, is really interesting on this topic.
@puilamwu2 жыл бұрын
@@AtticPhilosophy Thank you so much for the suggestion.
The ironic thing about this is that the whole system of symbolic logic and it's ideas don't really even exist in the sense that the material world does. If Pegasus can't be understood to exist at least in some symbolic sense, then why should any character of the language of logic?
@GreenEmperor3 жыл бұрын
Thank you, Dr Jago! Is this view related to the view you developed in your impossible worlds book?
@AtticPhilosophy3 жыл бұрын
You're welcome! The views aren't really related. Those who talk about 'thin existence' usually reserve it for possible entities, since most people don't want to say anything impossible exists in any sense.
@FffffffffffffffffffffffffffffL3 жыл бұрын
Hi Attic, I've already mastered basic logic and reason (truth tables, fallacies) and I've taken a class in symbolic logic as well, and I feel comfortable with that too. What are the next steps (topics) in learning logic?
@AtticPhilosophy3 жыл бұрын
Hi Vinny, there's loads of different directions you could take. If you want to learn more *kinds* of logic, there's modal logic (see the videos here), intuitionistic logic, and many-valued logic (videos on these coming soon). Or you could go deeper into the logic you've already looked at: proof theory (natural deduction, proof trees, sequent calculus), or meta-logic (soundness, completeness, decidability). Or you could look at philosophical issues (should Excluded Middle or Non-Contradiction be accepted?) Videos on that coming here soon.
@FffffffffffffffffffffffffffffL3 жыл бұрын
@@AtticPhilosophy Thanks Attic!
@FffffffffffffffffffffffffffffL3 жыл бұрын
@@AtticPhilosophy any plans to cover predicate logic?
@dylanl22582 жыл бұрын
How do you model haptia as a nexus of perspectives, a model of models? I'm not saying she didn't physically exist, but that the way her meaning exists as a summed up being (rather than as separate atoms or whatever) is all mitigated through perception. What role does that play in structural logic?
@AtticPhilosophy2 жыл бұрын
Is this the work of a random word generator?
@dylanl22582 жыл бұрын
@@AtticPhilosophy No. And that's a pretty harsh thing to write.. Are you interested in what I'm trying to ask, or just trying to be a jerk? The question is asked in good faith.
@dylanl22582 жыл бұрын
@@AtticPhilosophy And also, even if the wording isn't great, the idea isn't that hard to grok.
@AtticPhilosophy2 жыл бұрын
@@dylanl2258 The words in the question seem completely random. I don't know what haptia is, or 'nexus of perspectives', or what any of that has to do with a video on Quantified Modal Logic. Are you asking how logic represents a person or an idea or something like that?
@Nicoder6884 Жыл бұрын
Can you please clarify what you are talking about?