What is Logic? (Philosophical Definition)
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- Опубликовано: 4 июл 2024
- A definition of Logic as a field of philosophy, as well as several types of logic studied in philosophy, including second order logic, non-classical Logic, and modal logic.
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Information for this video gathered from The Stanford Encyclopedia of Philosophy, The Internet Encyclopedia of Philosophy, The Cambridge Dictionary of Philosophy, The Oxford Dictionary of Philosophy and more!
Information for this video gathered from The Stanford Encyclopedia of Philosophy, The Internet Encyclopedia of Philosophy, The Cambridge Dictionary of Philosophy, The Oxford Dictionary of Philosophy and more!
(#Logic #Modal)
Well I will need to watch this a few times.
How I feel about 1- *_every_* Carneades video 😹 and ESPECIALLY how I feel about 2- The 100 Days of Logic! 🙌🙌🙌
Seems like the logical thing to do in my opinion
You could just say, "Logic is a tool used to determine whether or not an argument can demonstrate its claim"
I like your definition
that is really the definition of reason. logic is really a jail, in which humans should not keep themselves
@@rootsgrassusa Why?
I don't think "tool is the right word to use here."
I would describe logic as the formalization of rationality.
logic is the art of thinking correctly. simple as
Damn, this channel deserves way more subs
you are wrong - this guy know nothing of Logic. Don't fool yourself. Let not language pollute you or convert you.
Subscribed. This is dope thank u.
For some reason the thought of "what is being rational?" popped in my head then I searched it and it said it was based on logic. Then I asked "what is logic?" and here I am
Yep. Glad you came. :)
I'd be very interested in videos on intuitionistic logic! While it is not too hard to find introductions to second order logic and set theory, I'm having a hard time finding introductory sources to intuitionistic logic. Also, since it is a more strict logic, I'd be very interested in hearing your thoughts, as a sceptic, on the problems that intuitionistic logic does and does not solve. In any case, thank you for the great videos!
Intuited reasoning is preconcious reasoning, as opposed to discursive reasoning, which is conscious reasoning.
I think you should do Second Order Logic, then Non-Classical Logic. Or the other way around. Anyway, I think that they both deserve a full series.
I agree that they each need a full series. I am looking to do it around the start of next year, depending on how busy I make myself. The consensus right now is doing second order and higher order logic first, but we will see how I'm feeling.
Also, where does Fuzzy Logic fit into this? Is that Non-Classical logic, Higher-Order logic, or something else?
+Nicolino Will Fuzzy logic is a non-classical logic, as it does not validate the Principle of bivalence.
your videos are truly awesome. can I use them to help teach my logic class?
You should! Someone at my university used them in their logic class, haha.
+Dare “DeuS eX DaRe” Jo' Of course! I encourage it. Thanks! And thanks for watching.
Please do more videos on Second order logic, especially pertaining to Set theory. Also do you have videos on propositional quantifier logic?
That's what I have been hearing form most people. Propositional quantifier as in "for all" and "there exists"? ruclips.net/video/7ahe8K0ZKiQ/видео.html Or Modal Logic (the logic of possibility, necessity, knowledge, ethics, and time)? ruclips.net/video/JHyfy0Chcs4/видео.html
Got this in recommendations now❤️
can u suggest some beginner level books on:
1/ overview of different kinds of logic
2/ books on specific major logic type
(pls suggest some popular ones, thank u)
Are you ever going to make videos on semantics, explaining the difference between the semantics for natural language and for formal languages?
I have a couple on the basics of semantics vs syntax (ruclips.net/video/zdoIfEKw3eU/видео.html), on formal languages (ruclips.net/video/ptyksCGBBn4/видео.html), and some basics on philosophy of language (ruclips.net/video/2LxIvDOtjpg/видео.html). I would love to do more on theories of meaning at some point, but who knows when.
Red herrings well we know it's not good for you it's not very practical judgment hence why kant called it the critique of pure reason
You're next series should be on Non-Classical Logics. :P It's a topic I enjoy studying, haha.
And maybe once you've done videos on the topics you mention in this video, you could do a video on how to pick between logics. My preferred answer (from the work of Graham Priest) is to appeal to a model of rational theory choice. :)
Interesting. Whenever I do something on Non-Classical, I will have to include how to pick a logic, I'll check out Priest's work to be sure.
Great video. Greetings from Mexico!
How about formal and informal logic? What’s the difference between them?
could you please suggest a good textbook, for the first order logic.
I have an access to an academic library of my university.
Help will be appreciated :)
I'd recommend Hurley's "A Concise Introduction to Logic", personally. :-)
There is a lot of good stuff. I would also recommend Hurley, though mostly what matters is the writing ability and what style you like, the actual content for most introductory textbooks will be the same.
+Carneades.org thak guys!!!!
thank you
So Logic is like Recursion. You have to use it to define it to use it and to define it and to use it ....
What about Vulcan logic?
perfect ! This gives very good intuition to a beginner !
Thanks!
This is the basic/same premise for Godspeak - the Conlang which basically describes the world using equations, where sentence structure comes from coding/programming with some PredCalc influences, semantics comes from Logic theory, Syllabic Structure/Views on reality comes from science and overall mechanics come from maths.
Very interesting, I'm sure such a language would have problems like the undefinability of truth. ruclips.net/video/ZH9TDXOPWqs/видео.html
Trapecio de Francisco Javier mansilla
Love your videos from Kenya.
Thanks! I hope all is well in Kenya.
Can it be improved? I'm bad at math + I'm bad programmer too, Idk if that was my lazy brain not learning something so long or?
Can it be improved like a skill or its just genes lie intelligence?
This video is designed to keep you confused .
The science of logic was invented by Aristotle during the fourth century B.C., as a systematic method of evaluating arguments in order to determine if they are properly reasoned. In his book "The Underground History of American Education" historian John Gatto argues very persuasively that, though the science of classical logic is taught in expensive private schools in the US today , it hasn't been taught in our State controlled public schools for more than a century. There are good reasons for this. It is hard to lie to people who know how to logically evaluate an argument. Due to our schools, even the vast majority of the elderly in our population have no effective understanding of the science of logic or the art of rhetoric. •••
"Logic, therefore, as the science of thought, or the science of the process of pure reason, should be capable of being constructed a priori."
-Arthur Schopenhauer, "The Art of Controversy", (1831)
("A priori" is defined as deduced from self-evident premises.) ••••••••••
"Logic: The science that investigates the principles governing correct or reliable inference. "
-"Webster's Unabridged Encyclopedic Dictionary" ••••••••••
"Infer ... v. ,1. To derive by reasoning; conclude or judge from premises or evidence ..."
-"Webster's Unabridged Encyclopedic Dictionary" ••••••••••
"For logic is the science of those principles, laws, and methods which the mind of man in its thinking must follow for the accurate and secure attainment of truth." -Celestine N. Bittle, "The Science of Correct Thinking: Logic", (1935) ••••••••••
"We suppose ourselves to posses unqualified scientific knowledge of a thing, as opposed to knowing it in the accidental way in which the sophist knows, when we think that we know the cause on which the fact depends, as the cause of that fact and of no other, and further, that the fact could not be other than it is".
-Aristotle, "Posterior Analytics" ••••••••••
"We ought in fairness to fight our case with no help beyond the bare facts: nothing, therefore, should matter except the proof of those facts."
-Aristotle, "Rhetoric" ••••••••••
"Without the presentation of solid evidence no argument can be a good one"
-Patrick Hurley, "A Concise Introduction to Logic", (1985) ••••••••••
"Fallacious reasoning is just the opposite of what can be called cogent reasoning. We reason cogently when we reason (1) validly; (2) from premises well supported by evidence; and (3) using all relevant evidence we know of. The purpose of avoiding fallacious reasoning is, of course, to increase our chances of reasoning cogently."
-Howard Kahane, "Logic and Contemporary Rhetoric", (1976), second edition ••••••••••
"The province of Logic must be restricted to that portion of our knowledge which consists of inferences from truths previously known; whether those antecedent data be general propositions, or particular observations and perceptions. Logic is not the science of Belief, but the science of Proof, or Evidence. In so far as belief professes to be founded on proof, the office of Logic is to supply a test for ascertaining whether or not the belief is well grounded."
-John Stuart Mill, "A System of Logic", (1843) •••••••••
"And if we have a right to know any Truth whatsoever, we have a right to think freely, or (according to my Definition) to use our Understandings, in endeavouring to find out the Meaning of any Proposition whatsoever, in considering the nature of the Evidence for or against it, and In judging of it according to the seeming Force or weakness of the evidence: because there is no other way to discover the Truth."
-Anthony Collins, "A Discourse of Free Thinking", (1713), taken from the first page of "Thinking to Some Purpose", by L. Susan Stebbing, (1939) ••••••••••
"Aristotle devides all conclusions into logical and dialectical, in the manner described, and then into eristical. (3) Eristic is the method by which the form of the conclusion is correct, but the premises, the material from which it is drawn, are not true, but only appear to be true. Finally (4) sophistic is the method in which the form of the conclusion is false, although it seems correct. These three last properly belong to the art of Controversial Dialectic, as they have no objective truth in view, but only the appearance of it, and pay no regard to truth itself; that is to say, they aim at victory."
-Arthur Schopenhauer, "The Art of Controversy", (1831) ••••••••••
"The fallacy of suppressed evidence is committed when an arguer ignores evidence that would tend to undermine the premises of an otherwise good argument, causing it to be unsound or uncogent. Suppressed evidence is a fallacy of presumption and is closely related to begging the question. As such, it's occurrence does not affect the relationship between premises and conclusion but rather the alleged truth of premises. The fallacy consists in passing off what are at best half-truths as if they were whole truths, thus making what is actually a defective argument appear to be good. The fallacy is especially common among arguers who have a vested interest in the situation to which the argument pertains."
-Patrick Hurley, "A Concise Introduction to Logic", (1985) ••••••••••
"A high degree of probability is often called 'practical certainty.' A reasonable man should not refrain upon acting upon a practical certainty as though it were known to be true. In England, for instance, it is customary for a judge, at the trial of a person accused of murder, to instruct the jury that an adverse verdict need not be based on the belief that the guilt of the prisoner has been ' proved ', but upon the belief that the guilt has been established ' beyond a reasonable doubt .' To be ' beyond reasonable doubt ' is to have sufficient evidence to make the proposition in question so much more likely to be true than to be false that we should be prepared to act upon the supposition of its truth. Many of our most important actions have to be performed in accordance with belief of such a kind."
-L. Susan Stebbing, "Logic in Practice", (1934) pages 98 and 99 ••••••••••
"An argument is a special kind of expression of inference , one that attempts to prove something on the basis of evidence."
-Patrick Hurley, A Concise Introduction to Logic, (1985), 2nd edition
"The statements that make up an argument are divided into one or more premises and one and only one conclusion. The premises are the statements that set forth the the evidence, and the conclusion is the statement that is claimed to follow from the evidence."
-Patrick Hurley, A Concise Introduction to Logic, (1985), 2nd edition
"A sound argument is a deductive argument that is valid and has true premises. Both conditions must be met for an argument to be sound, and if either is missing the argument is unsound. The qualification that the premises must be true means that all premises must be true. Because a valid argument is one such that if the premises are true it necessarily follows that the conclusion is true, and because a sound argument does in fact have true premises, it follows that every sound argument, by definition, will have a true conclusions as well. A sound argument, therefore, is what is meant by a "good" deductive argument in the fullest sense of the term."
-Patrick Hurley, A Concise Introduction to Logic, (1985), 2nd edition
"A cogent argument is an inductive argument that is strong and has true premises, and if either condition is missing the argument is uncogent. A cogent argument is the inductive analogue of a sound deductive argument and is what is meant by a " good" inductive argument without qualification. Because the conclusion of a cogent argument is genuinely supported by true premises, it follows that the conclusion of a cogent argument is probably true."
-Patrick Hurley, A Concise Introduction to Logic (1985), 2nd edition
Is it just me or the voice really sounds like Manny from Ice Age
How about a series on dialectics and Hegelian logic?
One day perhaps. Hegel's "logic" is a much broader topic than what we generally consider formal logic. And, as a continental philosopher he is not in the area of study that we generally cover. I will have a short video on him in the upcoming October series on famous philosophers, so stay tuned!
You are awesome
Logic is the codification of language - symbolizing concepts or truths with an object. If bigger reasoning systems consisting of the original objects were being symbolized by an object, is that second order philosophy?
Questions: how many and which logic does maths uses, and which one of these comes under which category of logic: deductive and inductive reasoning. And finally whats the difference between logic and reasoning
can someone help me what is logic and its relationship to wisdom, knowledge and philosophy ..
Logic is part of philosophy.
logic is a systematic tool, and it's a fundamental tool of philosophy; moreover, "wisdom" and "knowledge."
can someone recommend me a book on this topic?
I would just buy a well-ruputed logic textbook and that will be your best bet.
You now have my attention
your comment is logical.
TL;DR It's the rules that govern language. Need it simpler? It's words.
This is confused. What of Frege? Predicate logic with quantifiers is *the* logic studied today, unless the field has gone seriously astray. In this video it seems to have disappeared behind the ancient Categorical Logic, which no one uses. Also, propositional logic is not first order but, as it were, zeroth order.
Second order logic follow from the definition of the first order one. Are philosophers really that stupid that they don't see that or what? E.g. larger number than 2 has property of being larger. 3 is a larger number, thus it is larger than 2.
I'm not sure if you follow exactly what is meant by second order logic. Second order logic has to do with sets of objects and predicates. We are no longer just talking about what how all objects that have certain properties behave, we are talking about all sets of objects that have certain properties behave. First order logic makes claims like all men are sons. Second order logic makes claims like all relations that are transitive, symmetrical, and reflexive are equivalence relations. Here's more: ruclips.net/video/LPIWJ1tOM-E/видео.html
I thought a dog house would come up somewhere in this video.
Who made the rules?
a logical man of course, who else?
I need to buy you a new microphone. I see your videos all the time and I always have this instinct to not open them because I'm afraid of the shrill microphone. Otherwise, I would watch all 500 of your videos 'cause I'm addicted to philosophy.
I've been thinking about this ever since I started watching these. Although considering he's somewhere in west Africa the quality isn't half bad.
Not to say western Africa is technologically inept, but considering the price and quality of things such as internet one might want to make such an assumption.
He should set up a Patreon or something. Then people could just donate to him, haha
Yes, such a brilliant idea! What a pity he doesn't seem to have thought about it...
I am working on sound quality (even though just canceling the extra noise here is difficult), anything you would recommend in terms of audio editing would be appreciated. As for Patreon, I assume you are being sracastic: ruclips.net/video/XCPk_9X7XdY/видео.html
I still don't understand what logic means. Can someone explain and give some examples of logic please ?
The process of reasoning from assumptions/premises/observations to conclusions/theorems. If you think "If it is raining then I will be cold" "It is raining" therefore "I am cold" you are doing logic. By taking the first two claims and concluding the third.
so is logic when we use our reasons to come to a conclusion? And does the reasoning have to be valid?(a good reason)
I was wondering if you could give me a logical proof of the earth being a globe?
Personally I don't think logic is native to this universe. The law of non-contradiction permeates everything in the universe, yet general relativity and quantum mechanics, present in everything, run by different rules, meaning that somewhere in between there is a minimum unit of something that covers the teleportation to the following reality of quantum vs general. Why do I say minimum unit? Because, similar to Zeno's dichotomy of motion necessitating a chronon (a minimum unit of time) that is batted away by science as a general statement of "Nuh uh" because they can't state the obvious because they haven't proven it yet, all things in a series have a true minimum unit of one. Time, distance, thought, etc., all with some force charging the teleportation between these minimum units (I don't think its necessary to think of it as supernatural to apply it, though obviously I'm religious). Seeing as this seems to be true, what evidence can I bring to the table? Well, think of this, if cause and effect (not the principle of causality just the colloquial notion that things that happen have to have things before them that caused them) and energy are in infinite regress together they would have created a mind capable of controlling the entire universe, we can find no evidence of that, and so the infinite regresses cannot have been intertwined, logic entered energy at a specific point in time (as a religious person I argue by choice since changing two stable eternal natures requires input, but atheists would likely come up with another answer), and because energy has a minimum unit and so time and cause and effect there was a finite point where logic entered the universe, meaning logic has a minimum unit (I call them Thales) and so it can only effect certain things it can by its nature, much of the world is still illogical (afaik) and seems bonkers to species meant to understand it, guided by mystical forces like gravity, when a logical one would be a clockwork machine capable, in principle, of being created by using proper logic, even though logic simultaneously is the rule in the universe.
Intuitionistic logic plzzz
I'm afraid you're getting a few things wrong. In all, I like your videos, but as a tutor in logic I'd like to clarify some things:
- I find they way you outline the functions of semantics a little off. The syntax is a set of rules regimenting which combinations of symbols of the alphabet of a language are well-formed formulas (the analog of a grammatically correct sentence) and which are not. Semantics, on the other hand, are rules that govern under which circumstances atomic (the most basic) and complex formulas have which truth-values (in classical logic, the truth-values are true and false). Of course, sentential connectives in logics are supposed to express certain concepts, but what's most important for semantics is the notion of truth
- Validity is a notion closely related to semantics. Syntax shows that and exactly that which i outlined above. It does not show which inferences are valid. What you might mean is the fact that syntax in combination with a deduction system (that is, for example, a set of axioms and a set of deduction rules) shows which formulas are deducible within a formal system. Semantics, on the other hand, show us which formulas are logically true (and, if the deduction theorem holds, which inferences are valid)
- propositional logic is not considered first-order logic. First-order logic is an umbrella term for quantificational calculi that only allow variables to be bound by quantifiers. In classical logic, you use this term to refer to the systems CQC or CQC+= respectively
- "propositional calculus" is not a term referring to a combination of propositional logic and categorical logic. It simply refers to the deduction system of a propositional calculus
- higher-order logics are not the foundation of set theory. The axioms of set theory can be spelled out in terms of higher-order logics if you treat sets as singular terms, but set theory works perfectly without second-order calculi (historically, set theory was invented even before the first-order predicate calculus)
- the law of the exluded middle is not an axiom but a a rule that follows from the semantics of a given formal language
I appreciate comments and/or questions. Cheers!
Thanks. I am glad you like the videos. Thanks for watching. This is a simplified introduction which glosses over some of the finer points. That said, I take several issues with your claims.
First, read what I say carefully. The overly simplified definition of syntax that I offer is "the rules that symbols in a language follow". This is just a basic version of your definition. I offer a longer definition in my video on Syntax vs Semantics in line with yours.
Second, your definition of semantics is incorrect, or at least overly simplified. Truth is a function of meaning, not the other way around (a statement is true because of its meaning, it does not have a specific meaning because it is true). Semantics tells us what terms mean, and a theory of truth in turn tells us if that meaning makes our proposition true or not. For example, a coherentist and a correspondence theory of truth may have the same semantics for a proposition, ie claim that it means the same thing, but assign it different truth values. I am aware that outside of philosophy, sometimes semantics is just considered a list of true and false propositions, but in philosophy you need both a theory of meaning (semantics) and a theory of truth to get that. Here's the SEP for more (plato.stanford.edu/entries/meaning/ plato.stanford.edu/entries/truth/)
Third, I agree that you need syntax and a deductive system to show claims of validity, but I would argue that validity has much more to do with syntax than semantics. If you tell me the deductive system and the syntax, I can tell you whether p>q, p, therefore q is valid or not. I don't need to know either the truth value of the statements or their meaning. And that does not negate my simplified claim that the purpose of a syntax is to show which arguments are valid. It is a necessary, if not sufficient condition.
Fourth, how exactly one uses the terms "propositional logic" "propositional calculus" "CQC" etc. will depend on the textbook you are following. There is not universal terminology (much as different philosophers might use several different symbols for conjunction). I should point this out in the video, but that does not make my claim incorrect, just a basic version, suitable for an introduction.
Fifth by foundation, I perhaps mean more along the lines of "is reducible to" not "historically came before" which I think addresses your concern.
Finally, anything can be an axiom or a theorem depending on what you choose to assume and what you choose to prove. Either way, even if you don't assume the LEM, but choose to prove it, it follows from the deductive rules of the system and its axioms, not from its semantics.
Thanks for watching!
I'm everywhere but nowhere all at the same time.
If nothing exists, we all are. Vacuously at least. :)
If they are right, our entire cosmos may have sprung out of nothing at all. You might be on to something.
is that hipposus ?
Logic cannot be the bridge between English and Math. Logic is a subset of both English and Mathematics. Also, English is a subset of Mathematics. Mathematics is the language of Creation
I didnt know Kermit the frog teaches philosophy
Should i be skeptical about staying skeptical?
Insane
microphone...
Or maybe just read a dictionary instead guys so you will understand it easly
Tech No Logic is used to turn off your logic board.
Huh?
Why codify how some of us are able to think intuitively? Seems like we are giving away the cow, describing what should be a requirement for basic living and handing it to those not naturally equipped for its use. I figured out at age 8 that the world was full of adults who do not have these basic skills and have been horrified ever since that I have to share an earthly existence with these people. We shouldn't have to explain to people Common Sense; let Natural Cognitive Selection take its course.
Because fallacies are persuasive but invalid. People need to be shown that the most psychologically convincing argument may be fallacious or invalid. The point of logic is to codify this and teach people. Do you really think that people are incapable of understanding logic? A few hundred years ago, we thought most people lacked the cognitive capacity to learn to read, now it is expected. I am deeply skeptical of the claim that there are people who simply cannot learn.
Logic is the codification of language. What sort of stirfry definition is this? Who said language? Why of all topics you could have chosen to talk about at that moment you mentioned language? Why?
This is the definition that is generally accepted by the people that study logic: analytic philosophers. There may be other definitions, but as a channel focused on analytic philosophy that is what we are talking about.
How can anyone accept language as an element of logic? It's not possible
1+1=2 no! 1+1=8
hipposus
interesting your videos that i have seen on AI never comment on the basics of logic disproves that "AI" will ever be a thing. "weak AI" is not AI at all. Computers are syntax machines, they will never have any understanding of semantics. We take the syntax they calculate based on programming (humans putting semantical things into syntactical form so the computer can manipulate based on the rules of the code/hardware, and then they return more syntax that we then use our logic to turn back into semantical meaning.
Logic is the best rapper
Haha! Not that logic. :)
Logic is confusing there are different types of logic
Pokjjggd RT JL Francisco
Logic is an american rapper
koi milgaya....hi and hi again...with love amd.
Om shanti k good day please
Insanity
I’m even more lost than before I watched this video 🤦🏻♂️ Is that logical?
Check out the 100 days of logic for an intro ruclips.net/p/PLz0n_SjOttTcjHsuebLrl0fjab5fdToui
Dude your audio quality is so bad...
Boring! No wonder people think Philosophy is a bullshit subject how many times are you going to say logic?, or perhaps i don't get it
Logic Logic Logic Logic Logic Logic Logic Logic Logic Logic Logic Logic Logic Logic Logic Logic Logic Logic Logic Logic Logic Logic Logic Logic Logic Logic Logic Logic. :D
Philosophy is a lot more than just logic, if you are not interested in logic, I would encourage you to check out other areas of philosophy like ethics that have more direct applications to daily life if logic sounds boring.
The opposite of poetry
You should read Lewis Carroll's What the Tortoise Said to Achilles (ruclips.net/video/T2CRMrhNsQ0/видео.html).
Dude change your microphone or speak softer. Listening to you with headphones is painful.
Dude -you need to get your audio skills -up... otherwise your effort is a waste of everyone's time. Get a real mic, slow down, please, don't make the listener struggle to follow your spoken word ego.... I mean this as constructive criticism. I like your content -I just can't stand your production.
If you can't understand the audio feel free to turn on the subtitles. Many of my videos are recorded in West Africa where we don't have power much of the time, let alone good microphones or good places to record. I've tried to improve the audio quality over time (and I think it is better now than it was then), but generally I lean towards putting out more videos on a wider range of topics with lower production quality. I'd rather be one of the few with extensive series on Bayesian Epistemology and Deontic Logic than one of thousands making just a few high quality videos on the most popular philosophy topics.
@@CarneadesOfCyrene That's a good, logical idea. Thank you.