Simple if all As are Bs question..

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mrfatman
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Simple if all As are Bs question..

Post by mrfatman » Sun Dec 18, 2016 12:06 am

I don't study philosophy so I am sorry that my words and terms won't be familiar.

I saw this on a TV show now I am curious.

The question:

If all As are Bs

Some Bs are Cs

Therefore some As are Cs.

So the answer is "it depends on C as C is unknown".
But it seems this basically saying : If all As are Bs and some Bs are Cs is it always true that some As are Cs ?

Then that would be false.

Similar.

If all As are Bs.
not all Bs are Cs
is it possible to have A & C ?

Then this is not always true, so the answer is false ?

Impenitent
Posts: 1840
Joined: Wed Feb 10, 2010 2:04 pm

Re: Simple if all As are Bs question..

Post by Impenitent » Sun Dec 18, 2016 11:25 pm

If all pollen collecting honey makers are Bees

Some Bees sing falsetto

Therefore, Some pollen collecting honey makers are Bee Gees...

False only because they have left the building...

-Imp

ken
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Joined: Mon May 09, 2016 4:14 am

Re: Simple if all As are Bs question..

Post by ken » Mon Dec 19, 2016 2:14 pm

mrfatman wrote:I don't study philosophy so I am sorry that my words and terms won't be familiar.
I think this is not a case that people here will not be familiar with your words and terms but rather you are not familiar with the words and terms used in a discipline of teaching called "philosophy."
mrfatman wrote:I saw this on a TV show now I am curious.

The question:

If all As are Bs

Some Bs are Cs

Therefore some As are Cs.

So the answer is "it depends on C as C is unknown".
No, that is not the answer.

The answer is Therefore some As are Cs.

What do you mean by the 'it,' in "it depends on C as C is unknown"?

A is also unknown, and B is also unknown, so "it" (whatever it is) does not depend on anything.

If "it" means the question, then there are two things here now;

"It" is not a question. "It" is a syllogism. And,

If "it" refers to the syllogism, then nothing depends on C. If anything C is depended upon A and B. C is the conclusion formed from the two propositions named A and B.

mrfatman wrote:But it seems this basically saying : If all As are Bs and some Bs are Cs is it always true that some As are Cs ?
No, this is not asking a question. What this is really basically saying IS: If all As are Bs and some Bs are Cs, then it is always true that some As are Cs. The two words 'it' and 'is' are turned around so that this is not asking a question but rather telling us what IS.
mrfatman wrote:Then that would be false.
A syllogism does not ask for a true or false answer. A syllogism tells, or says, what IS true or false.

mrfatman wrote:Similar.

If all As are Bs.
not all Bs are Cs
is it possible to have A & C ?

Then this is not always true, so the answer is false ?
I am not sure how you could twist the last sentence around so much, but again this is not a question posed for an answer. 'It' is a formula used in logic to deduce, or arrive at, a conclusion, I think. I do not study a subject called philosophy either so I am also not familiar with the words and terms used in this subject.

uwot
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Re: Simple if all As are Bs question..

Post by uwot » Mon Dec 19, 2016 2:38 pm

mrfatman wrote:I don't study philosophy so I am sorry that my words and terms won't be familiar.

I saw this on a TV show now I am curious.

The question:

If all As are Bs

Some Bs are Cs

Therefore some As are Cs.
Logic just examines the structure of sentences and arguments, sometimes replacing words with symbols which can make it confusing. It's easier to understand by examples. For instance:
All mammals are animals.

Some animals are cats

Therefore some mammals are cats.

Hope that helps.

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vegetariantaxidermy
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Re: Simple if all As are Bs question..

Post by vegetariantaxidermy » Mon Dec 19, 2016 6:54 pm

uwot wrote:
mrfatman wrote:I don't study philosophy so I am sorry that my words and terms won't be familiar.

I saw this on a TV show now I am curious.

The question:

If all As are Bs

Some Bs are Cs

Therefore some As are Cs.
Logic just examines the structure of sentences and arguments, sometimes replacing words with symbols which can make it confusing. It's easier to understand by examples. For instance:
All mammals are animals.

Some animals are cats

Therefore some mammals are cats.

Hope that helps.
I was just going to say
If all cats are mammals
Some mammals are elephants
Therefore some cats are elephants.

uwot
Posts: 3624
Joined: Mon Jul 23, 2012 7:21 am

Re: Simple if all As are Bs question..

Post by uwot » Mon Dec 19, 2016 7:10 pm

vegetariantaxidermy wrote:I was just going to say
If all cats are mammals
Some mammals are elephants
Therefore some cats are elephants.
Good point. Well, that's logic for you.

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Terrapin Station
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Location: NYC Man

Re: Simple if all As are Bs question..

Post by Terrapin Station » Mon Dec 19, 2016 9:32 pm

Okay, first:

All As are Bs
Some Bs are Cs
Therefore some As are Cs.

This is an invalid argument. That it's invalid does not mean that the conclusion is false. The conclusion might be false. It might be true. We don't have enough information.

What are known as Venn diagrams are helpful for this.

We have three possibilities where all As are Bs and some Bs are Cs:

Image

Image

Image

In the first possibility, no As are Cs.

In the second, all As are Cs.

In the third, some As are Cs, some are not.

This doesn't have anything to do with what As, Bs and Cs actually represent. That doesn't matter. Logic is just about the formal relationships.


Re your other question:

If all As are Bs.
not all Bs are Cs
is it possible to have A & C ?

As you can see, all As are Bs and not all Bs are Cs fits the same three Venn diagrams I gave you above. So given the premises, you can have an A that's a C--you have As that are Cs in the second and third diagrams.

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Arising_uk
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Joined: Wed Oct 17, 2007 2:31 am

Re: Simple if all As are Bs question..

Post by Arising_uk » Mon Dec 19, 2016 9:43 pm

mrfatman wrote:I don't study philosophy so I am sorry that my words and terms won't be familiar.
No problem.
I saw this on a TV show now I am curious.

The question:

If all As are Bs

Some Bs are Cs

Therefore some As are Cs.
This is only true if you are saying all Bs are also As. If not it could be that all the Bs that are Cs are not As. In this case the conclusion would be false.

Hence VT's
"If all cats are mammals
Some mammals are elephants
Therefore some cats are elephants."

Which is patently false.
So the answer is "it depends on C as C is unknown".
Well a solution could be to look at the Cs to find one that is an A if one wished to find the truth but I guess that could depend upon how many Cs there were.
But it seems this basically saying : If all As are Bs and some Bs are Cs is it always true that some As are Cs ?
Not quite, what it's saying is "It is always true that if all As are Bs and all Bs are Cs and some Bs are Cs then some As are Cs".
Then that would be false.
If could be false if all Bs are not As.
Similar.

If all As are Bs.
not all Bs are Cs
is it possible to have A & C ?

Then this is not always true, so the answer is false ?
I take it you mean,

If all As are Bs
Not all Bs are Cs
therefore some As are Cs

Some As could be Cs but you can't deduce it from the propositions I think but stand to be corrected.

ken
Posts: 2075
Joined: Mon May 09, 2016 4:14 am

Re: Simple if all As are Bs question..

Post by ken » Tue Dec 20, 2016 8:33 am

vegetariantaxidermy wrote:
uwot wrote:
mrfatman wrote:I don't study philosophy so I am sorry that my words and terms won't be familiar.

I saw this on a TV show now I am curious.

The question:

If all As are Bs

Some Bs are Cs

Therefore some As are Cs.
Logic just examines the structure of sentences and arguments, sometimes replacing words with symbols which can make it confusing. It's easier to understand by examples. For instance:
All mammals are animals.

Some animals are cats

Therefore some mammals are cats.

Hope that helps.
I was just going to say
If all cats are mammals
Some mammals are elephants
Therefore some cats are elephants.
Are some mammals elephants?

I can see how elephants are mammals. But can a mammal really be an elephant?

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vegetariantaxidermy
Posts: 6916
Joined: Thu Aug 09, 2012 6:45 am
Location: Narniabiznus

Re: Simple if all As are Bs question..

Post by vegetariantaxidermy » Tue Dec 20, 2016 8:43 am

ken wrote:
vegetariantaxidermy wrote:
uwot wrote:
Logic just examines the structure of sentences and arguments, sometimes replacing words with symbols which can make it confusing. It's easier to understand by examples. For instance:
All mammals are animals.

Some animals are cats

Therefore some mammals are cats.

Hope that helps.
I was just going to say
If all cats are mammals
Some mammals are elephants
Therefore some cats are elephants.
Are some mammals elephants?

I can see how elephants are mammals. But can a mammal really be an elephant?
Certainly all of them aren't.

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