Criticism on Propositional Logic

Logic is a linguistic representation of our experience. Since logic is language, it does not create experience but describes experience.

The academic logic system is incomprehensible, it is more of a game than a common sense representation of experiences.

In basic propositional calculus, there is Conjunction (and), Disjunction (or), Negation (not).

Since ‘and’, ‘or’ ‘not’ are words without meaning indepent of context, their application ignoring our experiences is illogical, if we treat logic as representation of experiences.

The words themselves, the three connectives describe experience of having or not having (not), since we have multiple experiences, we can have one or more experiences linked together, thus ‘and’ ‘or’

The idiocy that arise in relation to reality is ‘true’ ‘false’
The word ‘true’ ‘false’ in themselves have no bearing on anything. They describe nothing in themselves but describe a state of experience.

The truth and falsehood of a linguistic statement can be verified only in relation to experience.

Take an example,

Harry is short and John is tall.

if indeed the sentence resembles our experience, then we say Harry is short and John is tall.
but if reality shows Harry is short and John is short, then the logician would say the statement is ‘false’. But what does ‘false’ say about experience? The word false said nothing. Does that mean, Harry is tall and John is short or Harry is short and John is short? The word false does not create a meaning of reality.

So in all logical instances, the speaker ought just describe the experience and not use words like ‘false’ or ‘true’ to mean anything, except when previously defined.

If I say today is 40C and tomorrow will be 50C. one of them is wrong, let us say tomorrow will be 30C, but simply to say ‘false’ would imply that today is not 40C. False does not say anything.

or if for instance I say tomorrow will not be 50C. does that say anything about temperature of tomorrow when I have not specified the range? No.

also,

in relation to the If…Then statement. When that is invoked the speaker is inovking one’s memory of a causal relationship. like If house caught on fire then it will burn down. you need a memory of it. Therefore children often do not comprehend the statements, and stupid adults think the kids are stupid, while they themselves are stupid. so the kids are bought up to think they are stupid while they are not.

Anyway, I just think logcian ought to learn to speak proper English, and get a life, they are not talking logically, but that they have invented their own language game based on validity and soundness. which detaches itself to reality.

POR

The beauty of logic is that it is context independent, it’s about structure and form rather than context and experience. Logic does not describe experience.

Your veiw of logic is fundamentally flawed. "and “or”, “not” do not require context in the sense that you use it. P or Q/ not P/ therfore Q doesn’t not use context. It is a matter of form and structure, with set laws, that allows for the preservation of truth. You shouldn’t understand ~ in terms of not, because that is obviously confusing you. Instead understand it as a negation and you no longer have the problem of experience as context.

Honestly I would get away from using the terms of true and false if you’re studying logic. Instead understand it in terms of sound/unsound and valid/invalid.

Logic is a set of rules, must how math is. We do not need to experience 5+4 to know that it is 9. Instead it is 9 because 9 is defined in that way. Logic is bound by definitions in a very similar way as math, and so it does not require experience. Every logical formula is proved not by experience, but by logical rules.

To do this would be to disarm the force of logic, if it has force.

Again, logic is a set of rules. ----> statements do not depend on the experience to be deemed logical or illogical. p–>q/p/ therefore q is valid based on rules and axioms, not on experience.

That is the whole point of logic. Could you image doing math without numbers, and instead just with fingers? It would be absurd and useless. You describe and advocate doing this to logic.

Nihilistic

nice to hear from you again. I like the way you reply.

But the structure and form of it is used to describe experience.
Plato is Man
Man is mortal
so plato is mortal

is really Another way of saying Plato is a mortal man. if you use A or B, or C to represent Plato, Man mortal then you are detaching yourself from experience or where we derive logic. though you may use substitutes, but really you are playing a language game with logic. Instead of saying plato mortal or man. why don’t you just take a look at Plato assuming he is still alive. you don’t need logic to see the world. Logic just represent the world in a specific invented rule.

i mean man is mortal, but not all mortals are men. is just stupid language game, something I think to do with Venn diagram, which is another absurdity. Logic is a language which describes experience in its on way.

The logic becomes a game, like a game of chess, totally independant of existence. sometimes I ask, what is represented by P or Q, what exactly is the person saying. if nothing is said, the it is just a game, with a set of rules by which you have to play by. just like playing a stupid game. how do you relate reality to P or Q is the question I am interested in. I am not interested in playing this P or Q game that so characterise logic.

I understand propositional logic, that is why I am criticising it. for there to be a ‘not’ there must be something else there. a person is not a woman is a man. which is another way of saying the person is a man.

yup, now how do you verify sound, invalid. without apealing to reality?

this is where you are wrong. 5+4=9 because when we have 5 apples, and put 4 apples more. we count and found out we have 9 apples. mathematics, especially arithmatics is simply describing experience. 5 and 4 are quantity describers. they are adjectives, and ought be used in relation to objects. not independently. because 5+4=9 is a meaningless game.

but logic is derived out of experience from which we impose our set of rules. all things logical can be verified through experience. if not, then you are playing a game involving As and Bs, and Cs without ever knowing what is A representing, or B representing. this study independent of reality is simply stupid and useless in the real world.

hahah, logic in its application has detached form reality, but to verify it, one only has to take a simple look at reality. we think of numbers in terms of things. you can not detach logic from reality without it becoming an absurdity.
e.g

All A is B

logic says does not mean All B is A.

but if I say

All men is mortal

does that imply the possibility that, it does not mean all mortal is men?

hahahahahahah.

Edit: Don’t people feel like a moron studying logic? I mean I feel like a moron just reading statements like ‘Johnny likes beer.’

Mostly fine, but: Unlike other languages, propositional language is only concerned with form (it is contentless). Thus, its not representing any particular experience, but the shape of experience as a whole. If experience is a house, then logic shows how the bricks fit together, not how any particular brick or collection of bricks looks.

Except for tautologies and contradictions. They are true and false respectively a priori. It is these tautologies and contradictions on which logic is based (or rather, revealed).

I see no idiocy here.

Tsk tsk. Logic is contentless. It makes no bones about the actual state of affairs (thats for the sciences), only what state of affairs are possible. What you are doing here is not propositional logic, but scientific investigation.

Kind of silly advise, since we already take that into consideration. Multiple and changing points of view, although not explicitly expressed, are implicit in ordinary language. All languages simply model possible states of affairs as if they are the case (mostly). Propositional logic is just more explicit about it.

Eh? Why can it not be 40C today and 50C tomorrow? If tomorrow is actually 30C, how is this a problem? It could have been, the fact that it happens not to have happened is a scientific problem to do with your predictive system, nothing to do with logic.

If you’d said “tomorrow it will be both 50C and 30C at the same time” i may be more logically concerned.

Not the case. If… then statements can be timeless, simultaneous, or even retrospective. Observe:
If the car is red then it is expensive. (timeless)
If the car is racing then it is moving. (simultaneous)
If the car is a TVR then it was made in Blackpool (retrospective)

Causality (in the troublesome future following the past sense) is not present here, instead its just defining the terms used.

I’m sorry. Given the number of mistakes in that paragraph… im just too amused to reply. :smiley:

PART TWO

You’ve missed the point. The example has NOTHING to do with plato or men, or mortality, it used only to illustrate the form of the argument. You could replace it with pretty much anything, and the logician will be fine and say its a logical equivelent. This is what is meant by contentless.
Eg.
PoR is my mum
My mum is a hippie
So PoR is a hippie

This is not independant of existence though, instead it describes the form of ALL existence, it is just independant of the PARTICULARS of an experience.

Why cant i be PoR and not be PoR at the same time? Because of the logical structure of the world, its simply not a possible state of affairs.

This is a pretty telling statement. Simple examples are used because complex ones are not required to demonstrate the form.

On a related note: Why havent you included a single statement of PL in your criticism of it?

I mean, this would be amusing, except its not PL, and its not a problem. For example: Animals are mortal and they are not men.
If i say: All dogs are quadrapeds, that does not mean all quadrapeds are dogs (some are cats).

Seriously, i recommend Tomassi’s Logic for a good in depth introduction, though there are some good introductory websites to.

Cheers

Logic is the boundry of human comprihension and as such it is self evident…

Logic is a factory… you put in experiences/propositios… out come conclusions…

The original premise ‘logic is language’ is faulty. A mute and illiterate man can still find his way through a maze.

you’re talking about a different thing here. PoR was pretty specific when he said “propositional logic” not logic as an abstract floaty entity (synonymous with rationality).

PL is a language with a grammar and vocabulary designed to show the rules governing the floaty entity.

Logic exists independant of its description…

of course it does, in fact, it cant be described directly without making alot of silly noises*. Instead it must be shown in action, and PL is a vehicle for that.

A criticism of PL is a criticism of its representation, not an attack on rationality itself (which, you know, is rationally pretty silly).

Cheers!

*try it yourself: what is negation (without reference to an example of it)?

You don’t understand what PL is. There are some great books -

Critical Thinking - A Concise Guide by Bowell and Kemp

Logic - by Paul Tomassi

These books will teach whats so great about PL but also it’s problems - and they’re not the ones you think they are.

The Converse of an A premise has an undetermined Truth Value.

All A is B - premise

All B is A - Converse

Due to the exclusive bi-potential:

A = B - in which case does B = A. (Leibnitz’s Law)

A is a subset of B - in which case B > A in Quantity, Quality, or both.

I read the first one during year one logic. Obw is right, it’s a very good book for someone who doesn’t know what PL is.

oh mine. what is the meaning of a proposition if all it has is the form and lacking in content. if all is concerned is form then it is like a book on gramar without the words, therefore not a language.

oreso

where did the form have their derivative? form came about because of experiences. we derive logical form out of experience. the study of logic, especially PL without content makes no sense, at all.

but how do you know how the bricks fit together without looking at the bricks themselves? i.e without words. I never speak of an independant brick but that if it is a collection of bricks, then it ought to say that and not some A or B.

they are neither true nor false, they are meaningless. much like a jumbo of letters like .dfadsadsfa

Logic derive out of experience, so to study it without content is absurd and misleading. all variables must have a meaning, or else the equation is just a game. what is possible is shown in experience. I am criticising PL, that to study meaning variables says nothing. PL is just rules in a game if it has no content.

the text books did not take that into consideration, Mrs Genius. that is why I am criticising it.

that is mean to show a single false says nothing.

what does that even mean? it is meaningless. has nothing to do with true or false, as they are implied.

I said ‘invoking one’s memory of a causal relationship’. meaning red is the cause of it being expensive. cause has nothing to do with time, but that one follows the others, neccesarily.

Since you said nothing, I’ll reply with … lovl

You still refuse to see the light. the argument is merely representing a particular experience in a special linguistic way. A contentless statement is meaningless. what does ‘A’ is ‘B’ mean? if it is independent of content. the example talks about plato and men but talks of them in a special way.

here you are only speaking of a particular but broken up in a special way.

because that statement is meaningless

I thought the example involving ‘and’ in weather is pretty obvious.

seriously, talk about logic as though it is timeless all you like. talk about it independant of everything all you like. because without involving experience all you are doing is playing a game called logic. enjoy the game!

If thats the terms you like, then thats it exactly. It is book on grammar, except it happens to be the grammar of the world. The sciences would then be the vocab. Can you see the awesomeness yet? We’re talking the form of the world itself regardless of the contents. The fundamentals of what can be and not be.

As for it not being a language. PL itself of course does have words, its just that they are meaningless variables designed to fill out the grammar. Instead of modelling a possible state of affairs with a focus on the particular ‘affairs’, it focuses on the ‘possible’ bit. No contentful words required if what you are expressing is the grammar itself. Thats the whole point.

Eh? you saying that we cant derive things from experience? What about scientific laws?

The ‘without content’ bit is just to satisfy the focus of study. People get confused when logicians use content to express logic (as with your concern over the simple sentences that are always used).

If it makes you feel better, replace that with ‘omni-contentful’. Variables dont have ‘no meaning’ they stand in for ‘all meaning’. Replace them with whatever you like, because they are meant to describe the form of all experience.

Just as physical laws are derived from experience and can be understood better without ‘content’, so it is with logic. The examples more often then not just get in the way. Its best just to stick to an interrelation of abstract variables so that people can grasp the scope and form of the concept under discussion rather than being bogged down.

Thats how we derived the logical laws in the first place, of course, but once we have done this, we no longer need to pay attention to any particular bricks at all. They simply arent the point under discussion. We can understand the laws that govern how bricks relate perfectly well without even seeing one.

Even more so with logic, as we are constantly ‘using our bricks’, ie. exercising logic. All that remains to be done is to make that process transparent so we can do it in more and more complex cases and more efficiently.

Tautology: always true. Contradiction: always false. So, er, how are they neither?
Moving on, of course they are without meaning, as they cannot possible describe any particular state of affairs, as they apply equally across all states of affairs. HOWEVER, they are the perfect vehicle for revealing what makes a ‘possible state of affairs’ possible. Quite simply, they describe all experience.

I posted a while back on the beauty of the law of non-contradiction, so if you are interested in how tautologies shape the world, then i can dig it up for you.

er. F=ma applies to all values of F, m and a. The understanding is that the actual value of these variables is inconsequential to understanding the law itself. Logic is only concerned with the law. True enough that what is possible is shown in experience, and with logic you will find how it was possible. If its a game, then its one helluva big damn metagame that applies to everything.

Logic shouldnt teach anything new to a rational being. There are no secrets. All it does is make our rationality (and that of the worlds) transparent so we can see it and use it better.

Thats because its not in the scope of the subject. Do you object to gardening books cos they dont reveal the workings of xylem and phloem tubes? Its taken as given.

Of course it is meaningless, it is a contradiction, that was the point. Since it is meaningless, i cant describe it to you, so in order to show folk what a contradiction is, you have to use one.

:smiley: ‘follows’ still suggests time you know. In anycase, how is memory being used if the things happen simultaneously or timelessly? I mean, “being a bachelor caused me to be unmarried” is silly. You cant just tar logical entailment and timeful causality with the same brush.

Not at all. The argument was not representing ANY experience, it was representing ALL experience. Given the contentful nature of our language however, we had to use a particular experience to illustrate. Btw, PL isnt logically superior in that represents logical form more accurately or something. Its only better because it doesnt carry any irrelevant contentful baggage.

[quuote]A contentless statement is meaningless. what does ‘A’ is ‘B’ mean? if it is independent of content. the example talks about plato and men but talks of them in a special way.
[/quote]
I cant describe what any particular logical law means, thats also the point. We can only show them. Thats why i issued the challenge to see if you could describe negation to me. If you dont understand the concept, then you simply arent rational. If you can use the concept, then you already understand it.

To repeat, i only use contentful particular examples because its a necessity of using english. With PL i dont have to.

How do you know it is meaningless? Thats because you intuitively understand a logical law called the law of non-contradiction.

Eh? Thats not PL.

Of course logic is timeless (rationality doesnt change), but our understanding of it isnt. PL, etc are our tools of understanding. For instance, you can add quantificational modifiers to handle arithmatic.

Of course it is also independant of everything. Why would it change from one room to the next? Even if i went to the ends of the universe, the law of non-contradiction would still apply.

I am not involving particular experience through wilful ignorance or something, but because it simply conceals the issue. Logic applies to all experience equally, so why muddy the waters when you are learning?

After you have learnt it you can apply PL to proper arguments, but application is not necessary for understanding.

Cheers!

PS. good to hear other folk like Tomassi. :slight_smile:

oh dear, I am going back to work tomorrow, so I won’t be able to reply maybe till saturday or sunday, so please don’t feel offended if I do not reply, especially when it is so long, I really can’t reply to all, I have not got the time.

The study of gramar in themselves is useless without using words. How can you communicate with others with only gramar. As I said, logic describes the experiences of reality. so you only have to interact with reality to verify a proposition. PL says very little. It is not a gramar but a sub-gramar. To replace propositions with variables like A or B, over simplifies common communication. To simply say A or B is true, false, is meaningless. because to analyse the form without the content says nothing in actuality.

A sentence without words and grammar is meaningless. and what does ‘‘is’’ mean in PL, if you know what I mean.

In short, PL over simplifies to the point of being un-understandably absurd.

you seem to be stealing my position, please read quote again.

the ‘with content’ bit tells people what is realy being said. the without content is not understandable, because they are just form, or gramar but gramar is applied, so there must be instances where gramar is applied. also to say PL is gramar is giving it too high a status.

I wrote

you wrote

if you know that then why reply? you seem to agree with what I am saying but making me sound like I do not agree with what I am saying.

I really have no idea what you are on, on one occasion you seem to agree, but disagree two lines later. what are you on about? if you agree with me then don’t re-explain what I explained. that seems to be what you have done with your entire post.

I wrote

I said, logic came from experience. My criticism is the use of true and false in relation to and, or, not.

and, or links things relationally. but not says nothing about the things except it is not that thing.

PL is useless in that it is narrow incomplete gramar that is not very helpful in daily communication. to say it is NOT hot does not say anything about the temp. PL is a study in stupidity. to simply say things as 'true false says nothign about reality themselves.

E.G to say A and B is false says nothing. does that mean A is false or B is false or they are BOTH false or one of them is false.

sorry for not replying to your re-explaination of my explanation. Gee, you are so wierd.

Pinnacle of Reason, what is with the Avatar? What is the symbolism behind the giant cross and the crosshair with two dots? Why does it read “Preserver Our Race” at the bottom? It’s weird.

It all has to do with his beliefs regarding coupling between people of different races.

If incomplete grammar renders a language useless then all language is useless. I don’t think you really understand logic, do you?

edit - if your objection is that logic is inherently divorced from actual experience (I’m having some trouble understanding you) then once again, what distinguishes logic from other language?

sfair 'nough.

The goal is not communication, but understanding. Of course you wont gain total understanding without the sciences, but thats a seperate issue and doesnt invalidate the importance of logic.

Not at all. You have to interact with reality to verify a logical law, but from that you can use as many different propositions as you like.

PL says absolutely nothing. Thats not its goal. No content! It is not the grammar itself, but a clear representation of portions of the grammar. All language represents this grammar to a degree, but not so clearly.

We arent communicating, but we are analysing the meaning of communication free from ambiguity. PL doesnt state that such and such is true or false (thats the sciences), but it calculates the consequences of both. “Possibilities” not “what happens to be the case”.

Of course i agree completely and ive said as such. But ‘meaning’ as you seem to be using the term is contentful. PL doesnt ‘mean’ anything, it just shows the logical law at work and thats all you can do.

There is no simplification. ~(p&~p) relates just as much of the logical law as “it cannot be that i am french and i am not french”, except it does so without ambiguity and without contentful baggage.

I have no problem with deriving laws, but i also think we can then use those laws and understand them in isolation.

Like i said, if we are using an analogy where logic is the grammar of the world, then PL is merely a representation of a portion of that grammar.

How does the lack of content inhibit understanding of the logical law? I understand ~(p&~p) perfectly well.

I agree with it as far as i said: we derive logical laws by relation to experience. However, I disagree that “some A or B” says any less about the logical law than referring to bricks or something. If a logical law applies to all experience, where is the need to refer to it only in relation to particulars as natural language must?

Yes logic comes from experience, but not from any particular experience.

IMPORTANT+++++
Ah. If i get your problem: you think that logic is in the business of determining the truth values of statements. Of course, contentless statements do not relate to a particular experience and thus cannot have a truth value.

As I said earlier, logic is not in the business of determining what happens to be the case (what happens to be true; this is for the sciences). Logic is for determining what is possible ONLY. No particular truth value is ascribed, but the consequences for all of them are calculated.

This may be helpful: ilovephilosophy.com/phpbb/vi … sc&start=0

The goal is not communication, but clarification. To say “nothing is better than X, i am better than nothing, thus i am better than x” is an example where natural language misleads, but PL could not. PL is a tool for showing logical law, not English MkII or something.

Cheers

Someoneisatthedoor that’s what I figured, but I would like to hear it from him directly. Though I don’t know why I care… I never read the initial post when PoR starts a thread. Usually by the time I am interested in a post which he has started the conversation between others has gone completely beyond whatever rant started the post.

To be honest PoR, I’m tired of seeing your pseudo-philosophy litter ILP like so many cigarette butts in a college-dropout’s parent’s basement. But I’m new to ILP; other people don’t seem to mind your constant ranting so who am I to say anything.

PS. Maybe our little fight a few weeks back is preconditioning my opinion of you but with that said you have to be most arrogant SoB I have ever seen on a BBS.