They're not. They reveal fundamental misunderstanding, confusions, and ignorance of the writer. — TonesInDeepFreeze

Do you, then think both books are good books contrary to the negative review details? How would you compare my 2 books to the one you recommended?

My criticism of the rants (those are not reviews) is independent of the books. What she said about logic is stupid, no matter what is in the books.

I looked only at the tables of contents of the books. The books seem to be meant for general students and to give a first overview of basic logic. My guess is that they are fine for that purpose. I would suggest studying them if you have nothing else. Kalish/Montague/Mar covers much of the same ground, but it's the best introduction I've seen, though probably it's more demanding than the other two books.

I started studying logic on my own. My first logic textbook didn't even have symbolic logic. Mostly about informal fallacies, a bit about syllogisms, and the difference between deductive logic and inductive logic. It was okay I guess. Then I worked through an introductory book on symbolic logic, and I learned a lot. Then I got Kalish/Montague (Mar was not a co-author of that edition). It covered basically the same ground as my first symbolic logic book, but I saw that it did a vastly better job of it. But I will say that I just don't know whether I would have done as well with Kalish/Montague if I hadn't previously read that other symbolic logic book that gave me some good chops with symbolization and symbolic deduction.

My criticism of the rants (those are not reviews) is independent of the books. What she said about logic is stupid, no matter what is in the books. — TonesInDeepFreeze

I thought she was not saying Logic is stupid. Rather, she was saying that the books don't mention some important points in Logic. She quotes a few philosophical texts from the other authors and philosophers about logic and how general people study and practice Logic, and why those missed points in the books are critically important.

I have never studied Logic as such in serious manner. Everything I said and wrote about logic was from my common sense and reasoning. Then I thought it couldn't do any harm if I do some reading on logic.
I was then looking for some logic books. There were so many logic books on the market, I could not tell which one is good or bad.

I got the 2x which were randomly chosen, but when I scanned them, thought they are not that great.
I didn't find the writing style interesting or clear.

Then I worked through an introductory book on symbolic logic, and I learned a lot. — TonesInDeepFreeze

But I will say that I just don't know whether I would have done as well with Kalish/Montague if I hadn't previously read that other symbolic logic book that gave me some good chops with symbolization and symbolic deduction — TonesInDeepFreeze

What is your the other symbolic logic book before the K/M which gave you some good chops with symbolization and symbolic deduction?

A good tool is the Venn diagram. Represent animals by a big circle. Dogs is a smaller circle inside the big circle. Cats is another smaller circle inside the big circle, not intersecting with Dogs. You now have four possibilities. The area outside the circle is non-animals. The area inside the big circle and outside the other two is all the animals that are not dogs and not cats. The dogs are in the dogs circle and the cats are in the cats circle.

This is a visual representation of propositions and implications. E.g. 'If x is a cat, then x is an animal', 'If x is not an animal, then x is not a dog' are shown as a picture. You can see that 'If x is a cat, then x is a dog' is false under all possibilities: there is no intersection of the two circles.

____________________

Truth tables will do the same job but for the question you have in mind they may be a bit unwieldy.

The Gensler Logic book has good explanation on the Venn Diagram.
Will have a look.

But I also thought the OP argument problem stems from the premise that there is limited scope for the definition of dogs and cats. Simply saying "are animals" is not sufficient definition for them.
So, dogs are animals and dogs bark.
Cats are animals and cats meow.

from more definitions given in the premises, it would have had a true conclusion.
cats are not dogs (they are both animals, but cats don't bark, dogs don't meow)

So, it demonstrates how insufficient premises render wrong conclusions in the argument, even if they look valid.

In God debates, often the premises they start are either wrong and insufficient, hence the argument arrives at the wrong conclusion, or / and it falls into confusion in the middle of reaching the conclusion.

For instance, the wrong and insufficient definition "God is omnipresent, omnipotent and omniscient" or "God is a necessary being" as the premises of the arguments will not only confuse the following arguments but also arrive at the wrong conclusion.

Because if one start ask and analyse all those concepts of God, then it will be clear there is no ground to assert them as true definitions, and even if we infer them as true definitions, the scope of the premises is limited for the arguments and conclusion.

So, it demonstrates how insufficient premises render wrong conclusions in the argument, even if they look valid.

But the conclusion does not follow from the premisses. d->a and c->a does not entail d<->c. All dogs are animals; and all cats are animals; however, no dogs are cats.

The problem is not in the definitions. The problem is that you say a conclusion follows when it does not follow.

To see that it does not follow you need to draw the diagram or write out the truth table: those are the tools we need for this job.

The problem is not in the definitions. The problem is that you say a conclusion follows when it does not follow. — Cuthbert

But did you read the new argument with the extra (sufficient) definitions added in the premises then produces the new true conclusion? = cats are not dogs.

Yes. You do not need extra definitions. The original definitions are quite sufficient. Dogs are animals. Cats are animals. Cats are not dogs. Those last three statements are consistent. You need the diagram and the truth table.

Yes. You do not need extra definitions. The original definitions are quite sufficient. Dogs are animals. Cats are animals. Cats are not dogs. Those last three statements are consistent. You need the diagram and the truth table. — Cuthbert

Hmmm I would have thought you don't need the diagram, but you just need to add more definitions into the premise making it sufficient and necessary condition. Wouldn't it be more convenient and practical than drawing diagrams in the debates? (if it were debate situations) :)

Had a quick look at the Venn Diagram section of the Gensler book, and it looks OK.
But I was wondering whether the diagram method is only OK for simple arguments with just 1 or 2 premises.

There are often cases of arguments with 10 - 20 premises in the real life arguments. In this case, I wonder if the diagrams could serve as a practical tool for the arguments at all.

I said you might find Venn diagrams useful because it looked in the OP as if you initially believed 'All dogs are animals' and 'All cats are animals' entail the conclusion 'All dogs are cats', which they do not. I thought the diagrams might help with that, if it was a problem. Truth tables are another useful tool.

I see.  It was a demonstration OP for showing that logical arguments in philosophical debates do need solid sufficient definitions and premises so that they will arrive at infallible True conclusions.
Truth tables and Venn diagrams are great tools too. But more for the educational purpose, I feel.

Sorry for butting in like this but have you noticed, Agrippa's trilemma is part of every philosophical debate? One particular problem Agrippa identified 2,000 years ago keeps popping up like the sun everyday in the eastern skies viz. axiomatization - the battle between opposing camps is centered around the key premises which on occasion spills over into matters of consistency/inconsitency. That's my take though - nothing official about it!

It was a demonstration OP for showing that logical arguments in philosophical debates do need solid sufficient definitions and premises so that they will arrive at infallible True conclusions.
Truth tables and Venn diagrams are great tools too. But more for the educational purpose, I feel. — Corvus

As usual, it comes down to what the scribbles point to, or how they are defined. — Harry Hindu

I like to solve these types of problems using a computer programming language. In every language, the variables need to be defined in order to use them. In every logical process the variables used refer to something in the world. They are pre-defined and their definition needs to be taken into account as part of the logical process. So for every logical proposition you need to remember that each scribble needs to be defined prior to the proposition like a=1, b=2, x=a+b, y=(a,b,x) (this is an array and is similar to a category in ordinary language) etc.

Also, if you find that some logical proposition produces a false conclusion, its because some other logical fallacy was made. All logical rules have to be followed - no cherry-picking.

I was not aware of Agrippa before, but it seems also interesting topic to read and learn about. Thanks for the info.
https://ideasinhat.com/2018/11/16/what-is-the-munchhausen-trilemma/

Thanks for the info. — Corvus

My pleasure. Did you read this :point: New Caledonian Crow?

I like to solve these types of problems using a computer programming language. In every language, the variables need to be defined in order to use them. In every logical process the variables used refer to something in the world. — Harry Hindu

Sure. I used to do some computer programming myself, and used to use, WHILE .... DO, For x> y DO,
or IF ... THEN and write up FUNCTIONS a lot to carry out checking the conditions.

You know fine well, that to check some complicated conditions, the statements needs many lines of coding to check for all the possible conditions. The use of the variables are essential in the programmings. One condition out of many in the loop or IF THEN sections fails, the whole program fails and comes to halt (if the input is out of boundary set in the variables and error handling code is not implemented), or it will return FALSE value from the functions or routines to the calling modules straight, not even bothering going on checking for the next conditions.

Also, if you find that some logical proposition produces a false conclusion, its because so other logical fallacy was made. All logical rules have to be followed - no cherry-picking. — Harry Hindu

Yeah, that was what I have been saying all along. If you get your staring definitions and also any of t he premises wrong, then you can end up with some crazy conclusions as Truth. Dangerous things for sure.

You know fine well, that to check some complicated conditions, the statements needs many lines of coding to check for all the possible conditions. The use of the variables are essential in the programmings. — Corvus

You can always use coding to restrict users to certain conditions and choices, thereby limiting the amount of coding you have to write that checks for "all possible" conditions.

Yeah, that was what I have been saying all along. If you get your staring definitions and also any of t he premises wrong, then you can end up with some crazy conclusions as Truth. Dangerous things for sure. — Corvus

Dangerous is not the word I would use. Strict and uncompromising are terms that I think of when reflecting on logic.

Did you read this :point: [url=https://thephilosohttps://thephilosophyforum.com/discussion/comment/566809phyforum.com/discussion/comment/566809]New Caledanian Crow[/url] — TheMadFool

No I haven't. I have no much knowledge on the medieval time religious topics. I must go back to Russell's History of Philosophy and do some more readings on the chapter to be able to follow the thread, I think.

Dangerous is not the word I would use. Strict and uncompromising are terms that I think of when reflecting on logic. — Harry Hindu

Deconstructive use of the word :D (All uses of the problematic and unclear words have been contributed or excused to that term by me recently - xD how convenient )
I tend to be sarcastic to my own writings often - never mind.

No I haven't. I have no much knowledge on the medieval time religious topics. I must go back to Russell's History of Philosophy and do some more readings on the chapter to be able to follow the thread, I think. — Corvus

:ok: Forget I even mentioned it. It was irrelevant to the discussion.

Forget I even mentioned it. It was irrelevant to the discussion. — TheMadFool

I opened the thread, but immediately realised the topic is one of the subjects, that I am not familiar with. Time permitting and the background reading done, I am inclined to have another go.

Please do what you wish. No promises though.

:up: :smile:

I thought she was not saying Logic is stupid. — Corvus

I didn't say she said logic is stupid. I said that what she said about logic is stupid.

Rather, she was saying that the books don't mention some important points in Logic. — Corvus

SHE claims those are important points. Her remarks reveal that doesn't understand what logic is about.

She quotes a few philosophical texts — Corvus

Yes, typically crank: Argument by compilation of selective quotation.

Meanwhile, perhaps you would pick a quote that you think supports her criticisms of the books.

Before she even gets to the quotes she fires her loose cannon with a claim that is tantamount to saying that not just are the logic books wrong and amiss but that they are pernicious to mankind itself. She's a nutjob.

What is your the other symbolic logic book before the K/M — Corvus

I'd rather not say, because I think it's not a good book. It wasn't the book in particular that gave me chops, but rather any book with a good number of exercises also would have given me the chops.

She wrote about the Hodges book:

"Here's what he does explain:
(1) Logical arguments begin from true premises.
(2) Logical arguments begin from premises and come to conclusions which are free of obvious contradiction."

I will stand corrected, but I don't see how that could be a correct paraphrase of anything Hodges wrote.

(1) Logical arguments don't require true premises. A SOUND argument requires true premises.

An argument is valid iff any model in which the premises are true is a model in which the conclusion is true. Validity does not require that the premises be true in any particular model or even any model at all.

(2) Logical arguments don't ensure contradiction-free conclusions. Rather, a logical argument ensures a contradiction-free conclusion if the premises are contradiction free. It is not required that the premises be contradiction-free. And the word 'obvious' mindlessly thrown in there clouds principle she's stating (though the principle is incorrect anyway).

She's an ignoramus.

the OP argument problem stems from the premise that there is limited scope for the definition of dogs and cats. — Corvus

It has nothing to do with domains or definitions.

The problem stems from the fact that the argument posted is invalid, as has been explained.

it demonstrates how insufficient premises render wrong conclusions in the argument, even if they look valid. — Corvus

The argument doesn't look valid. It is clearly invalid.

true definitions — Corvus

What is your definition of 'true definition'?

you just need to add more definitions into the premise making it sufficient and necessary condition. — Corvus

What definitions would you add? What sufficient and necessary condition?

I was wondering whether the diagram method is only OK for simple arguments with just 1 or 2 premises. — Corvus

Venn diagrams are profoundly useful. But they are limited. There are logical arguments they don't test.

Maybe there's a theorem somewhere that says exactly what is the class of arguments decided by Venn diagrams.

But we do know that truth tables decide all propositional arguments.

it is possible for the arguments to come to the true conclusion, had the premises came up with the complete set of sufficient and necessary propositions — Corvus

What is your definition of 'the complete set of sufficient and necessary propositions'?