• Leontiskos
    2.9k
    Gonna call it for tonight and rethink stuff, though obviously not in your favor :DMoliere

    Fair enough. :wink:

    I'd appreciate you answering my question about whether or not paraconsistent logic would count as a plural logic insofar that we accept both paraconsistent logic and classical logic.Moliere

    Yes, I didn't really understand it, and it seems like neither you nor I have a firm grasp on what it means for something to be a paraconsistent logic. Like probably everyone on TPF, I have read about paraconsistent logic as I read about animals in a far off land, but I have never worked with it or made use of it. They seem to be used mostly in the way that Aldous Huxley used his encyclopedia entries.

    Are you asking me whether I think that accepting both paraconsistent and explosive logic results in the robust kind of logical pluralism? My guess is that I would answer 'no.' Paraconsistency does not entail Dialetheism. And paraconsistent logic is often used informally in everyday life (if that counts). I also haven't seen anyone in this thread who favors logical pluralism embrace Dialetheism - other than yourself, of course. They seem to be mostly Augustinians, "Lord, give me logical pluralism, but not yet!"
  • Leontiskos
    2.9k
    - Fair enough. Or I suppose the person could respond to the quibbler, "If the center was deleted—per impossibile—then there would only be an Aristotelian Circle."

    Perhaps you can see my complaint. Given that the sort of mathematics we are engaged in is in an important sense limited only by our imaginations, so too quibbles are limited only by our imaginations. For example:

    Edit: And why can't a quibbler say that R^3 and even R^2 spaces are not Euclidean? What's to stop him? When is a disagreement more than a quibble?Leontiskos

    The flip side of this is that mathematical concepts seem to become purely stipulative and imaginary when viewed in such a way. In that case the ground rules for something like propositional logic lose all coherence and plausibility—as do all concepts—once we have dispensed with the notion of the true or useful. It then becomes nothing more than Banno's "symbol manipulation." That's why I keep asking things like this:

    But the deeper issue is that I don't see you driving anywhere. I don't particularly care whether the great circle is a Euclidean circle. If you have some property in your mind, some definition of "great circle" which excludes Euclidean circles, then your definition of a great circle excludes Euclidean circles. Who cares? Where is this getting us?Leontiskos
  • fdrake
    6.5k
    Edit: And why can't a quibbler say that R^3 and even R^2 spaces are not Euclidean? What's to stop him? When is a disagreement more than a quibble?Leontiskos

    Oh. Because the definition of a Euclidean space, in the modern sense, includes both. They're infinite expanses of points whose interpoint distances are given by straight line distance. In the old sense, in Euclid's sense, only R^2 could be, since R^3 isn't a surface.

    "If the center was deleted—per impossibile—then there would only be an Aristotelian Circle."Leontiskos

    It's interesting really. Since deleting the point from the plane impacts lots of possible circles. There will be Euclid circles in that space which are not Aristotle circles too, I believe. Though I'm not totally convinced.

    But the deeper issue is that I don't see you driving anywhere. I don't particularly care whether the great circle is a Euclidean circle. If you have some property in your mind, some definition of "great circle" which excludes Euclidean circles, then your definition of a great circle excludes Euclidean circles. Who cares? Where is this getting us?Leontiskos

    The discussion about capturing the intended concept is relevant here. The interplay between coming up with formal criteria to count as a circle and ensuring that the criteria created count the right things as the circle. That will tell us what a circle is - or in my terms, what's correctly assertible of circles (simpliciter).

    That's the kind of quibble we've been having, right? Which of these definitions captures the intended object of a circle... And honestly none of the ones we've talked about work generically. I believe "A closed curve of constant positive curvature" is the one the differential geometry man from above would've said, but that doesn't let you tell "placements" of the circle apart - which might be a feature rather than a bug.
  • Leontiskos
    2.9k
    There will be Euclid circles in that space which are not Aristotle circles too, I believe.fdrake

    Sure.

    I believe "A closed curve of constant positive curvature" is the one the differential geometry man from above would've saidfdrake

    Yes, or:

    We could say that a circle is a [closed] figure whose roundness is perfectly consistent.* There is no part of it which is more or less round than any other.Leontiskos

    The discussion about capturing the intended concept is relevant here. The interplay between coming up with formal criteria to count as a circle and ensuring that the criteria created count the right things as the circle. That will tell us what a circle is - or in my terms, what's correctly assertible of circles (simpliciter).

    That's the kind of quibble we've been having, right? Which of these definitions captures the intended object of a circle... And honestly none of the ones we've talked about work generically. I believe "A closed curve of constant positive curvature" is the one the differential geometry man from above would've said, but that doesn't let you tell "placements" of the circle apart - which might be a feature rather than a bug.
    fdrake

    But what is the "intended concept"? Presumably it is an intuitive concept, and are intuitive concepts mathematical formalisms? I wouldn't think so. So:

    It might not be a confusion, it could be an insistence on a unified metalanguage having a single truth concept in it which sublanguages, formal or informal, necessarily ape.fdrake

    Why think that the intended concept is a formalism, a mathematical equation? Similarly, why think that logic is a formalism, a logical system? Perhaps logic is as I've said: that which produces discursive knowledge. It is a natural or anthropological reality, not a prepackaged formalism.
  • fdrake
    6.5k
    We could say that a circle is a [closed] figure whose roundness is perfectly consistent.* There is no part of it which is more or less round than any other.Leontiskos

    That reads disingenuously to me. Your use of "roundness" previously read as a completely discursive+pretheoretical notion. If you would've said "I think of a circle as a closed curve of constant curvature" when prompted for a definition, and didn't give Euclid's inequivalent definition, we would've had a much different discussion. I just don't get why you'd throw out Euclid's if you actually thought of the intrinsic curvature definition... It seems much more likely to me that you're equating the definition with your previous thought now that you've seen it.

    The latter of which is fair, but that isn't a point in the favour of pretheoretical reasoning, because constant roundness isn't a concept applicable to a circle in Euclid's geometry, is it? Roundness isn't quantified...

    Presumably it is an intuitive concept, and are intuitive concepts mathematical formalisms?Leontiskos

    Mathematical concepts tend to be expressible as mathematical formalisms, yeah. And if they can't, it's odd to even think of them as mathematical concepts. It would be like thinking of addition without the possibility of representing it as +.

    not a prepackaged formalism.Leontiskos

    And therein lies a relevant distinction. Formalisms aren't prepackaged at all. In fact I believe you can think of producing formalisms as producing discursive knowledge!
  • Leontiskos
    2.9k
    But you also seem to think the context you have in mind for any question that arises is the only context it can possibly arise in.Srap Tasmaner

    Rather, if the context is different then the geometrical response is different, and I have no dog in the fight over the question of "family resemblances" as applied to geometrical abstractions. I have claimed that there are not square circles, not that "circle" can only ever be utilized within a single context.
  • Leontiskos
    2.9k
    That reads disingenuously to me. Your use of "roundness" previously read as a completely discursive notion. If you would've said "I think of a circle as a closed curve of constant curvature" when prompted for a definition, and didn't give Euclid's inequivalent definition, we would've had a much different discussion. I just don't get why you'd throw out Euclid's if you actually thought of the intrinsic curvature definition... It seems much more likely to me that you're equating the definition with your previous thought now that you've seen it.fdrake

    I gave that option before giving Euclid's. You are the one who brought up Euclid in the first place, but I really don't see the two descriptions as competing.

    The latter of which is fair, but that isn't a point in the favour of pretheoretical reasoning, because constant roundness isn't a concept applicable to a circle in Euclid's geometry, is it? Roundness isn't quantified...fdrake

    Pretheoretical or intuitive reasoning need not be quantified, does it? In making that comment I was making the point that pretheoretical reasoning represents the same basic idea as the calculus definition you gave. "...In calculus [consistent roundness] cashes out as a derivative, but folks do not need calculus to understand circles. Calculus just provides one way of conceptualizing a circle."

    Mathematical concepts tend to be expressible as mathematical formalisms, yeah. And if they can't, it's odd to even think of them as mathematical concepts. It would be like thinking of addition without the possibility of representing it as +.fdrake

    Well then I would ask whether the intuitive concept that is the intended concept is a mathematical concept. When a child learns to place circle-shaped blocks in circle-shaped holes they are not involved in formal geometry.

    And therein lies a relevant distinction. Formalisms aren't prepackaged at all. In fact I believe you can think of producing formalisms as producing discursive knowledge!fdrake

    Or rather, producing a thing that can produce discursive knowledge. And knowing a true logical system is a kind of knowledge, which is probably discursive. I think that's right. But they are prepackaged in a very relevant sense, particularly for those of us who are not their inventors.

    But I also don't think a logic like Frege's is merely a model, nor that it could be. To invent a logical system is to attempt to capture a (or the?) bridge to discursive knowledge, and I don't know that any success or failure is complete.
  • fdrake
    6.5k
    You are the one who brought up Euclid in the first place, but I really don't see the two descriptions as competing.Leontiskos

    Ah. That's unfortunate. Euclid's definition makes the great circle not a circle. The closed curve one makes it a circle.

    Pretheoretical or intuitive reasoning need not be quantified, does it? In making that comment I was making the point that pretheoretical reasoning represents the same basic idea as the calculus definition you gave. "...In calculus [consistent roundness] cashes out as a derivative, but folks do not need calculus to understand circles. Calculus just provides one way of conceptualizing a circle."Leontiskos

    It's the same basic idea, yeah. When understood in the context of a circle. You can think of curvature as a more general concept than roundness, since curvature's also "pinchiness" and "pointiness". and "flatness" etc all rolled into one. So it's sort of like roundness is to curvature as apples are to fruit.

    Or rather, producing thing that can produce discursive knowledge. And knowing a true logical system is a kind of knowledge, which is probably discursive. I think that's right. But they are prepackaged in a very relevant sense, particularly for those of us who are not their inventors.Leontiskos

    It's both innit. Getting the definitions right is one thing - yay, you have found the commonality between circles. Using the definitions to produce even more knowledge is another.

    But I also don't think a logic like Frege's is merely a model, nor that it could be. To invent a logical system is to attempt to capture a (or the?) bridge to discursive knowledge, and I don't know that any success or failure is complete.

    I don't think any of the examples we've discussed so far is "merely" a model, since the different frameworks place much different commitments and demands on the behaviour of people that use them.

    One of the great things about producing formalisms is that they're coordinative. If you and I operated on the constant curvature definition, we'd be committed to the same beliefs about circles. The same with the Euclid one. When you add that to our ability to mathematise abstractions expressively in a common language, you end up being able to write down the mathematical rules one must follow when dealing with an abstraction - just in case you have successfully defined it in the symbols. At that point, whether it is the right abstraction for the job seems a different issue.

    I certainly wouldn't tell my students that a circle is a closed curve of constant curvature, I'd show them examples of circles and just say "like this". Roll them about. Measure them. I wouldn't even show them Euclid, or try to define the shape. For a lot of things you can get an okay idea of what they are without a formalism, but that loses its charm when you need to explore things that have less straightforward intuitions associated with them.

    Like the example I gave of continuous functions vs Darboux functions (functions with the intermediate value property). Mathematicians thought those were equivalent for a long time based on pretheoretical notions.
  • Count Timothy von Icarus
    2.7k


    Now what do you make of this? I've understood you as saying Tarski is unavoidably deflationary, and that this is a bad thing.

    As I've said repeatedly, STT need not be deflationary. It is often taking as a means of modeling correspondence truth and this leaves the door open for judging "correct logics" in terms of their ability to preserve correspondence truth not simply truth relative to some formal context.

    But STT can also be rendered deflationary, and Frank has given us some sources indicating that this is more how Tarski himself considered the theory (which jives with what I've read of his work).

    As for it being a "bad thing," that's an entirely different conversation. The question is: "is deflation question begging or at the very least a highly relevant and contested premise when considering logical nihilism vs pluralism vs monism, such that its implicit assumption is problematic?"

    I don't see how the answer could possibly be anything but "yes." If one starts with a strong deflationary position it seems trivial to show that no laws of logic hold with generality. But monists are normally arguing for monism in a non-deflationary context, in terms of "correct logics." Monism is true for "actual truth preservation" not "truth preservation relative to an arbitrary context."

    For example, G&P's target is the natural language logical consequence relation. The scientific position's target is entailment in the sciences. The metaphysical position is talking about logical consequence from the perspective of metaphysical truth.

    And nihilism also seems to need to avoid deflation because nihilism is a position about logic in general or "all correct logics." If the nihilist adopts a strong deflationary position for the purposes of undercutting monism then they are guilty of equivocating when they try to tell the pluralist that there are no laws of truth preservation for logic as a whole. Deflationary nihilism is simply pluralism, the nature of truth preserving logical consequence varies by context.

    But again, virtually no one wants to claim that truth should be both deflated and allowed to be defined arbitrarily. So we still have the question (even in the permissive case of Shapiro) about what constitutes a "correct logic." The orthodox position is that this question is answered in terms of the preservation of "actual truth." But we also see it defined in terms of "being interesting" (e.g. Shapiro). Either way, we are right back to an ambiguous metric for determining "correct logics," hence to common appeals to popular opinion in these papers.
  • Cheshire
    1.1k
    This seems like a useful clarification of terms. Where I have seen the term used, and how it is used in the papers we have been discussing, the idea is that there is no logical consequence relationship. It is not that there is no general consequence relationship that obtains in all cases. The idea that there are truth-preserving rules of logical consequence but that they might vary is called logical pluralism.Count Timothy von Icarus

    I agree, speaking the same language always helps. Based on this I would fall more in the nilishist camp I suppose. The truth of the conclusion isn't a consequence of the premises. I could make most arguments backwards. Any assertion of truth comes with the 'consequence' and it is true or and it is false.

    Nihilism seems more to me like we all have wood blocks and jigsaws and we can cut out whatever we please. Which, as an analogy for "how does one derive conclusions from true premises," seems like a poor one if one has any notion that truth is not some sort of post-modern "creative act."Count Timothy von Icarus

    Isn't this just an attempt to dismiss the idea out of hand? I suppose if I thought nihilism was wrong I would posit that the relationship between ideas can be by free association(under nihilism), but I wouldn't confuse it with a compelling position.
    This is why deflationism is question begging. You can set up the argument like so:

    1. Truth is defined relative to different formalisms.
    2. Different formalisms each delete some supposed "laws of logic," such that there are no laws that hold across all formalisms.
    3. The aforementioned formalisms each have their own definition of truth and their systems preserve their version of truth.
    C: There are no laws vis-á-vis inference from true premises to true conclusions.
    Count Timothy von Icarus

    This sounds more like arguing against the "no general" bit of the definition that you claimed doesn't apply. I guess I'm confused as to what question I'm begging. Do people think that ordering statements they've asserted as true eliminates the possibilty of error? Something more than a persuasive assertion?

    There's no formula for making a false statement true when it isn't. So, formulation doesn't cause the truth of something. It simply presents the reasoning in an arguably unnatural way. The truth of things is constrained by the facts and the state of affairs, not the way I choose to write it down. What question is that unfair to? Thanks for the explanation though, I tried to parse it best I can.
  • Count Timothy von Icarus
    2.7k


    So, formulation doesn't cause the truth of something. It simply presents the reasoning in an arguably unnatural way. The truth of things is constrained by the facts and the state of affairs, not the way I choose to write it down.

    I agree with underlined point completely. The scientific and metaphysical arguments for monism tend to be abductive arguments based on this idea. This is why deflation is problematic as a background assumption. It needs to be an explicit premise, else we end up talking past each other, since the disagreement is really about what is properly "truth-preserving" in the most perfect* sense, not about what is true of formal systems and the logical consequence relationships each uses.

    As for the bolded part, I think this is something many monists, pluralists, and nihilists would agree with. Logical consequence is about truth preservation in arguments, not causation, or "that in virtue of which something is true."

    Yet, we might ask, "is cause unrelated to logical consequence?" That's a common presupposition in contemporary discussions of logic. It was not a popular position for most of the history of logic though. The ideal argument is propter quid, explaining why something is true (demonstrative syllogism). Not all arguments are thought to be of this sort of course, only some.

    This sort of thinking is still alive and well in relevance logic and occasional attacks on material implication.

    Anyhow, I think you get at a good point, in that I can imagine that many who subscribe to "classical metaphysics" (i.e. the serious "neo-neoplatonists" today, or Thomists) might actually agree with the nihilist that laws, as in short, stipulated formulae, are incapable of capturing the logical consequence relationship because they cannot capture analogical predication of truth and being properly. But I think they would disagree in concluding that the logical consequence relationship can be either arbitrary or unintelligible as a unity. Just for an example, I don't think Eriugena's four-fold distinction of being where "to say 'angels exist' is to negate 'man exists'" (when using exists univocally) is going to fit nicely into formal context. You could add four distinct existential quantifiers related by some sort of formalism of analogy, but I don't think that's going to cut it.

    * I couldn't think of a better term here than "perfect" in the sense that scholastic logic uses it. In this context, blindness is a perfect privation for a dog or a man because, by nature, these things see. Whereas we can say "non-seeing" of a rock or tree, but this is not perfect privation. The differentiation here is that truth might be said analogically of something being "true relative to some stipulated formulation of truth," but this is not true in the same way "George Washington is dead," is made true "by the world."
  • Leontiskos
    2.9k
    But again, virtually no one wants to claim that truth should be both deflated and allowed to be defined arbitrarily. So we still have the question (even in the permissive case of Shapiro) about what constitutes a "correct logic." The orthodox position is that this question is answered in terms of the preservation of "actual truth." But we also see it defined in terms of "being interesting" (e.g. Shapiro). Either way, we are right back to an ambiguous metric for determining "correct logics," hence to common appeals to popular opinion in these papers.Count Timothy von Icarus

    Right. As I said earlier, a basic challenge for the pluralist is to show which logics are acceptable/correct and which are not. I haven't seen anyone in the thread attempt such a feat, and if that can't be done then I'm not sure a serious position is being put forward. The same could be said for nihilism or monism, but no one has claimed such positions.
  • Count Timothy von Icarus
    2.7k


    Well Beall & Restall at least have a tighter definition. Shapiro's "eclectic pluralism" is based on "being interesting." But triviality is interesting. Does this mean logics where everything expressible can be shown to be true are "truth-preserving?"

    I think you need to assume deflation here for that to make any sense. If we aren't willing to go that far then we can still speak of how they "preserve truth," internally, in an equivocal sense, but that's it.
  • Leontiskos
    2.9k


    Seems right.

    There is also a really odd thing that happens constantly on TPF (and it usually happens with SEP). Someone will champion a position like logical pluralism or dialetheism or something like that, but when it comes down to the question of what exactly they are promoting they are at a loss for words. They don't have any clear definition of, say, logical pluralism.

    So we go to a secondary source like SEP or Griffiths and Paseau. But as soon as the content of the position is being taken from SEP and not from the TPFer we are no longer engaging/arguing with that TPFer. The TPFer had superficially identified with logical pluralism without being able to say what logical pluralism is, or what they mean by it, and when one flies over to SEP they have overlooked the crucial nature of this conundrum. SEP is not going to tell us what the TPFer thinks; it is only going to tell us what the author of SEP thinks. The thread becomes the discussion of a position that no one in particular holds, and that no one in particular has a stake in. In my opinion this outlines one of many misuses of SEP on TPF. Yet there is a fascination in our contemporary culture with labeling and labels!

    ...And to be specific, after this thread was necro-bumped Banno did the thing, "Yay for logical pluralism! Boo for Leontiskos and his logical monism!" What did Banno mean by logical pluralism? He had no real idea. Why did he think I was committed to logical monism? Again, probably no idea, although everyone took him at his word (!). It was a half-baked thought meant to stir up controversy, and that is the heart of the problem. Bringing in something like SEP is not going to make that initial move impressive or substantive.
  • fdrake
    6.5k
    There is also a really odd thing that happens constantly on TPF (and it usually happens with SEP). Someone will champion a position like logical pluralism or dialetheism or something like that, but when it comes down to the question of what exactly they are promoting they are at a loss for words. They don't have any clear definition of, say, logical pluralism.Leontiskos

    I would be pretty happy to defend logical nihilism as set out in Russell's paper.
  • Cheshire
    1.1k
    I agree with underlined point completely. The scientific and metaphysical arguments for monism tend to be abductive arguments based on this idea. This is why deflation is problematic as a background assumption. It needs to be an explicit premise, else we end up talking past each other, since the disagreement is really about what is properly "truth-preserving" in the most perfect* sense, not about what is true of formal systems and the logical consequence relationships each uses.Count Timothy von Icarus

    Thanks for the generous read and I'm still looking up some of these references. I suppose I have cake and eat it to approach to deflation. I think we we can know the truth of things. I don't think we have complete access to when that is the case and when it isn't. So its deflationary in the sense that truth claims are only assertions, but the truth itself isn't. Its a thing to be approximated. A type of perfect in this same sense.

    Anyhow, I think you get at a good point, in that I can imagine that many who subscribe to "classical metaphysics" (i.e. the serious "neo-neoplatonists" today, or Thomists) might actually agree with the nihilist that laws, as in short, stipulated formulae, are incapable of capturing the logical consequence relationship because they cannot capture analogical predication of truth and being properly. But I think they would disagree in concluding that the logical consequence relationship can be either arbitrary or unintelligible as a unity. Just for an example, I don't think Eriugena's four-fold distinction of being where "to say 'angels exist' is to negate 'man exists'" (when using exists univocally) is going to fit nicely into formal context. You could add four distinct existential quantifiers related by some sort of formalism of analogy, but I don't think that's going to cut it.Count Timothy von Icarus

    I'm still missing the jump from a symbolic system lacks the richness of embedding found in natural language to - logical consequence is arbitrary or unintelligible as a unity. Following your discussion with Leontiskos I get how "interesting" might be on the right path. To say there's a link between a formulated argument and the compulsion to accept it doesn't seem outrageous by any stretch. I just think it's naturally limited to saying, this is why I think I'm right versus why I must be right. The 'right' part is still "truth" properly inflated. But, it's relative to a person and we come with mistakes. Not to say logic doesn't get us closer and contradictions don't indicate a likely error, but neither are flawless indications of inflated truth. So, nihilistic with respect to guarantees, but realistic in thinking ideas ought to be consistent.

    I've always noted that disagreements about 1 thing, imply a disagreement about another. Is that a concession to anti-nihilism?
  • Leontiskos
    2.9k
    - Good to know.

    - Good points.

    One of the great things about producing formalisms is that they're coordinative.fdrake

    Coordination, cooperation, intersubjective agreement, etc., really tends to be the goal and limit of contemporary thinking. I think such things are useful, but I also think that at some point we have to venture out beyond the bay and into the open sea.
  • fdrake
    6.5k
    I think such things are useful, but I also think that at some point we have to venture out beyond the bay and into the open sea.Leontiskos

    I do enjoy the open sea, I just tend to think its openness is necessary. If you'll forgive me the excess of portraying metaphysical intuition through vagueness.
  • Leontiskos
    2.9k


    I would agree that every quantification is into a domain, and I don't think there are context independent utterances. I do not think it follows that there is no metaphysics. I'm rather fond of it in fact, but the perspective I take on it is more like modelling than spelling out the Truth of Being. I think of metaphysics as, roughly, a manner of producing narratives that has the same relation to nonfiction that writing fanfiction has to fiction. You say stuff to get a better understanding of how things work in the abstract. That might be by clarifying how mental states work, how social structures work, or doing weird concept engineering like Deleuze does. It could even include coming up with systems that relate lots of ideas together into coherent wholes! Which it does in practice obv.fdrake

    And this sounds a lot like Srap's approach. I was encouraging him to write a new thread on the topic.

    Plato's phrase, "carving nature at it's joints," seems appropriate here. I would say more but in this I would prefer a new or different thread (in the Kimhi thread I proposed resuscitating the QV/Sider thread if we didn't make a new one). I don't find the OP of this thread helpful as a context for these discussions touching on metaphysics.
    Leontiskos

    It seems to me that Sider's thread is the better place for this, but what you describe here doesn't really sound like metaphysics at all. The only point that sounds like metaphysics is the fanfiction metaphor, but if the fanfiction cannot be good or bad then one cannot be doing metaphysics, and are you willing to say that the fanfiction can be good or bad?
  • fdrake
    6.5k
    and are you willing to say that the fanfiction can be good or bad?Leontiskos

    Yes. Harry Potter and the Methods of Rationality is definitely better written than My Immortal.
  • Banno
    24.8k
    As I've said repeatedly, STT need not be deflationary. It is often taking as a means of modeling correspondence truth and this leaves the door open for judging "correct logics" in terms of their ability to preserve correspondence truth not simply truth relative to some formal context.Count Timothy von Icarus

    Well at least we have agreement that the Semantic Theory is noncommittal as to deflation or correspondence. I'm at a bit of a loss as to what happens next. You say that the correct logic is the one that "preserves correspondence truth". Does that mean that correspondence gets to decide between logics? How could that work? Is the correctness of logic to be decided empirically?

    And I'm now not sure if you are claiming that there is only one logic, and hence monism, or if you are saying that there are indeed multiple logics, only one of which "preserves correspondence truth".

    And it remains unclear to me why you introduced deflation into the conversation.

    I'm sorry, I just have not been able to follow what you are claiming.

    One of the issues in this thread is indeed the nature of logical pluralism. Deal with it as you will, but repeatedly attacking me is petty.
  • Banno
    24.8k
    It seems it is worth showing that paraconsistent logic is useful. Have a look at Applications from the IEP article. A google search will reveal uses in engineering and computing.

    The IEP article ends with
    Affirming coherence and denying absurdity is an act, a job for human beings.
  • Count Timothy von Icarus
    2.7k


    Does that mean that correspondence gets to decide between logics?

    When people writing on this topic discuss "correct logics," what exactly is it you think they are referring to? If all logics are correct logics then nihilism is obvious.

    Is the correctness of logic to be decided empirically?

    Yes, this is why G&P refer to the challenge as "broadly epistemic." Personally, I think the correspondence theory of truth is deficient, I only use that as an example because that is how it is most often conceived of.

    And it remains unclear to me why you introduced deflation into the conversation.

    If you assume deflation, I don't get how nihilism isn't a consequence. Truth just is truth as defined by some system. There are systems that both define a notion of truth and variously dispense with each of the proposed "laws of logic." Ergo, there are no laws of logic. What else more is there to say? If there is a logic that dispenses with LNC, then LNC cannot be a law of logic, etc.
  • Banno
    24.8k
    When people writing on this topic discuss "correct logics," what exactly is it you think they are referring to?Count Timothy von Icarus
    To be sure, it's not a term I would use. Logics are useful, applicable, valid, consistent, incomplete and so on, but not so much "correct".

    If all logics are correct logics then nihilism is obvious.Count Timothy von Icarus
    Why? If
    Truth just is truth as defined by some system.Count Timothy von Icarus
    what follows is that there are logical laws that apply within each system. What does not follow is that there are no logical laws.

    Is the correctness of logic to be decided empirically?

    Yes,
    Count Timothy von Icarus
    So there are multiple logics?
  • frank
    15.7k
    When people writing on this topic discuss "correct logics," what exactly is it you think they are referring to? If all logics are correct logics then nihilism is obvious.Count Timothy von Icarus

    In the same way moral pluralism is nihilism? Yes.

    If you assume deflation, I don't get how nihilism isn't a consequence. Truth just is truth as defined by some systemCount Timothy von Icarus

    Truth deflationists usually think of truth as having a social function. It's just something people say. That's different from using the truth predicate in a technical way as Tarski did.
  • Banno
    24.8k
    Deflation is simply the observation that asserting something and saying it is true are truth-functionally equivalent. The cat is on the mat if and only if "The cat is on the mat" is true.

    How you decide that the cat is on the mat - by observation, deduction or consulting a clairvoyant, is beside the point.
  • Cheshire
    1.1k
    So there are multiple logics?Banno

    Cirtangles for the win
  • Count Timothy von Icarus
    2.7k


    In the same way moral pluralism is nihilism? Yes

    I don't think so. The pluralist says there are multiple logical consequence relationships that preserve truth in different contexts. The nihilist would be saying there is no logical consequence, or put another we "we decide which logical consequence we want to consider correct." Or, as Russell puts it: "there is no logic."

    You can see the difficulty of equivocating or refusing to elaborate on what the "truth" in "truth-preserving" means here.

    Truth deflationists usually think of truth as having a social function. It's just something people say. That's different from using the truth predicate in a technical way as Tarski did.

    Indeed, there are different flavors of deflation. "Using the truth predicate in a technical way" isn't deflation at any rate. Deflation would involve the claim that truth just is whatever technical definition one decides to use. If one justifies STT with the claim that it "mirrors correspondence," "is the closest we can get to truth," or something to that effect, one isn't being deflationary.



    To be sure, it's not a term I would use. Logics are useful, applicable, valid, consistent, incomplete and so on, but not so much "correct".

    In virtue of what is a logic "applicable"?

    what follows is that there are logical laws that apply within each system. What does nto follow is tha there are no logical laws.

    How about this, why don't you explain to me why you think pluralism and nihilism are even different positions? And why do you think monism remains the dominant position?

    So there are multiple logics?

    This is an ambiguous question (which the articles shared here generally tend to point out in the introduction). If the question is "have people created systems with different logical consequence relationships?" the answer is obviously yes. But given your line of questioning this seems to be what you think the debate is about.
  • Banno
    24.8k
    Well, I imagine that can't use observation to decide between logics unless there are multiple logics.
  • Count Timothy von Icarus
    2.7k


    When Russell call nihilism "the view that there is no logic," do you think she is denying that any logics exist?

    Am I being trolled here?

    To be sure, it's not a term I would use. Logics are useful, applicable, valid, consistent, incomplete and so on, but not so much "correct".

    This isn't an answer to the question though. What do you think is being meant by "correct logic" in these articles?

    To clarify, this is the opening sentences of the article you wanted to discuss:

    "Logical monists and pluralists disagree about how many correct logics there are; the monists say there is just one, the pluralists that there are more. Could it turn out that both are wrong, and that there is no logic at all?"

    You're acting as if this is some bizarre concept it is impossible to understand though.
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