## POLL 3 on the validity of a simple argument on Joe the Squid

What is the basis for reason? And mathematics?

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## Is the argument valid?

No
1
100%
Yes
0
I don't know
0
The argument doesn't make sense
0

Speakpigeon
Posts: 957
Joined: Sat Nov 11, 2017 3:20 pm
Location: Paris, France, EU

### Re: POLL 3 on the validity of a simple argument on Joe the Squid

Atla wrote:
Sat Jan 26, 2019 12:09 pm
Two ways come to mind to show that it's invalid:
1. Squid, giraffe and elephant are all distinct, so Joe can't be both elephant and another one at the same time.
2. We can drop 3 lines
Yes but, please, don't say stuff like that! People are already confused enough as it is.
I would say myself, "we can ignore the three premises P1, P2 and P4 as logically irrelevant to the conclusion".
Still, I agree on substance.
Atla wrote:
Sat Jan 26, 2019 12:09 pm
Joe is an elephant
An elephant is not a squid
Therefore, Joe is a squid
Third line here contradicts the first two.
Good. Perfect. Thanks, a bit of sanity is always good to take.
So, you don't go with the definition of validity that they favour in "classical" mathematical logic which implies that the argument is valid because its premises are necessarily false?
EB

Speakpigeon
Posts: 957
Joined: Sat Nov 11, 2017 3:20 pm
Location: Paris, France, EU

### Re: POLL 3 on the validity of a simple argument on Joe the Squid

Age wrote:
Sat Jan 26, 2019 2:01 pm
One could also suggest that some are not capable of doing what they are expecting others to do here.
Yes, sure, you can go.
EB

Age
Posts: 2324
Joined: Sun Aug 05, 2018 8:17 am

### Re: POLL 3 on the validity of a simple argument on Joe the Squid

Speakpigeon wrote:
Sat Jan 26, 2019 2:13 pm
Age wrote:
Sat Jan 26, 2019 2:01 pm
One could also suggest that some are not capable of doing what they are expecting others to do here.
Yes, sure, you can go.
EB
Go where?

If you want me to play your game then I will.

Age
Posts: 2324
Joined: Sun Aug 05, 2018 8:17 am

### Re: POLL 3 on the validity of a simple argument on Joe the Squid

Speakpigeon wrote:
Fri Jan 25, 2019 4:02 pm
This is a poll on the logical validity of the following argument:
A squid is not a giraffe
A giraffe is not an elephant
An elephant is not a squid
Joe is either a squid or a giraffe
Joe is an elephant
Therefore, Joe is a squid
Is this argument logically valid?
EB
This argument is not logically valid because:
1. So called premise 4 and 5 contradict each other.
2. So called premise 4 and 5 do not contradict each other but that is not made clear.
3. The so called conclusion does not follow the so called premises.
6. If joe is an elephant but an elephant is not a squid, then joe could not be a squid. The conclusion is false.
6. The first three lines do not need to be stated, as they are obviously true.
7. The conclusion does not logically follow from the previous two lines.
8. 'Joe' is not any thing other than a name, which is just a label placed onto some other actual thing.

I am pretty sure there are other reasons in there, but just at the moment i could not be bothered looking for them.

surreptitious57
Posts: 3082
Joined: Fri Oct 25, 2013 6:09 am

### Re: POLL 3 on the validity of a simple argument on Joe the Squid

Speakpigeon wrote:
surreptitious57 wrote:
The last two premises contradict each other so the argument is invalid
Here is the definition of validity broadly accepted in classical mathematical logic :
Speakpigeon wrote:
An argument is usually said to be logically valid if all cases in which the premises are true the conclusion is also true
Or equivalently an argument is said to be valid if there is no case in which the premises are true and the conclusion is false
And here is what you yourself say of validity :
surreptitious57 wrote:
A valid argument is one where the conclusion is true in relation to the premises and nothing else
Because the conclusion is not true in relation to all of the premises only some of them
The conclusion and final premise contradict each other and so the argument is invalid

Atla
Posts: 1889
Joined: Fri Dec 15, 2017 8:27 am

### Re: POLL 3 on the validity of a simple argument on Joe the Squid

Speakpigeon wrote:
Sat Jan 26, 2019 2:09 pm
So, you don't go with the definition of validity that they favour in "classical" mathematical logic which implies that the argument is valid because its premises are necessarily false?
Well.. I can't even make sense of this: "the argument is valid because its premises are necessarily false". The argument is valid because it's unsound? Does not follow.

I guess I keep it simple: I only work with true premises and use simple one-step classical logic on them, or some sort of one-step probabilistic/fuzzy logic.

Speakpigeon
Posts: 957
Joined: Sat Nov 11, 2017 3:20 pm
Location: Paris, France, EU

### Re: POLL 3 on the validity of a simple argument on Joe the Squid

Age wrote:
Sat Jan 26, 2019 2:16 pm
If you want me to play your game then I will.
Still here?! Whoa, you really have nowhere else to go.
EB

Age
Posts: 2324
Joined: Sun Aug 05, 2018 8:17 am

### Re: POLL 3 on the validity of a simple argument on Joe the Squid

Speakpigeon wrote:
Sat Jan 26, 2019 2:58 pm
Age wrote:
Sat Jan 26, 2019 2:16 pm
If you want me to play your game then I will.
Still here?! Whoa, you really have nowhere else to go.
EB
Are you trying to derail from the fact that you are incapable of doing what you are expecting others to do here, or that you just do not want to do what you expect others to do here?

Speakpigeon
Posts: 957
Joined: Sat Nov 11, 2017 3:20 pm
Location: Paris, France, EU

### Re: POLL 3 on the validity of a simple argument on Joe the Squid

Age wrote:
Sat Jan 26, 2019 2:29 pm
I am pretty sure there are other reasons in there, but just at the moment i could not be bothered looking for them.
Yeah, and I can't be bothered either.
EB

Speakpigeon
Posts: 957
Joined: Sat Nov 11, 2017 3:20 pm
Location: Paris, France, EU

### Re: POLL 3 on the validity of a simple argument on Joe the Squid

Age wrote:
Sat Jan 26, 2019 3:01 pm
Are you trying to derail from the fact that you are incapable of doing what you are expecting others to do here, or that you just do not want to do what you expect others to do here?
The derail is you.
EB

Age
Posts: 2324
Joined: Sun Aug 05, 2018 8:17 am

### Re: POLL 3 on the validity of a simple argument on Joe the Squid

Atla wrote:
Sat Jan 26, 2019 2:52 pm

I guess I keep it simple: I only work with true premises and use simple one-step classical logic on them, or some sort of one-step probabilistic/fuzzy logic.
But you do NOT only work with true premises.

Age
Posts: 2324
Joined: Sun Aug 05, 2018 8:17 am

### Re: POLL 3 on the validity of a simple argument on Joe the Squid

Speakpigeon wrote:
Sat Jan 26, 2019 3:01 pm
Age wrote:
Sat Jan 26, 2019 2:29 pm
I am pretty sure there are other reasons in there, but just at the moment i could not be bothered looking for them.
Yeah, and I can't be bothered either.
EB
So I give you eight reasons why YOUR argument is NOT logically valid, with maybe more to come, but you could not be bothered looking at them and replying.

This highlights, and shows, more of your inabilities. Either you know all along that your so called "simple argument" is obviously logically invalid, you have just realized this, or you are under some sort of illusion that it is in fact logically valid.

Atla
Posts: 1889
Joined: Fri Dec 15, 2017 8:27 am

### Re: POLL 3 on the validity of a simple argument on Joe the Squid

Age wrote:
Sat Jan 26, 2019 3:03 pm
Atla wrote:
Sat Jan 26, 2019 2:52 pm

I guess I keep it simple: I only work with true premises and use simple one-step classical logic on them, or some sort of one-step probabilistic/fuzzy logic.
But you do NOT only work with true premises.
Not always 100% true, but I try. You however pull "universal knowledge truths" out of your backside, and you think they are coming from God/the universe/whatever.

Speakpigeon
Posts: 957
Joined: Sat Nov 11, 2017 3:20 pm
Location: Paris, France, EU

### Re: POLL 3 on the validity of a simple argument on Joe the Squid

surreptitious57 wrote:
Sat Jan 26, 2019 2:32 pm
Because the conclusion is not true in relation to all of the premises only some of them
That would be irrelevant. For example:
x is A
y is B
B is C
Therefore, y is C
Isn't that valid even though the first premise is irrelevant to the conclusion?
surreptitious57 wrote:
Sat Jan 26, 2019 2:32 pm
The conclusion and final premise contradict each other and so the argument is invalid
In real life, yes, but you have to assess the validity of an logical argument on the basis of what the premises and the conclusion mean and assuming the premises are true, not on whether they are actually true or false.
So, in this case, you can't just assume that an elephant is not a squid. And so, you can't assess the validity of the argument on the basis of the last premise and the conclusion alone. You need also need premise 3 that says "An elephant is not a squid".
EB
Last edited by Speakpigeon on Sat Jan 26, 2019 3:52 pm, edited 1 time in total.

Age
Posts: 2324
Joined: Sun Aug 05, 2018 8:17 am

### Re: POLL 3 on the validity of a simple argument on Joe the Squid

Atla wrote:
Sat Jan 26, 2019 3:11 pm
Age wrote:
Sat Jan 26, 2019 3:03 pm
Atla wrote:
Sat Jan 26, 2019 2:52 pm

I guess I keep it simple: I only work with true premises and use simple one-step classical logic on them, or some sort of one-step probabilistic/fuzzy logic.
But you do NOT only work with true premises.
Not always 100% true, but I try.
My apologies i did not read it fully as i thought speakpigeon wrote that.

As for if you only work with true premises or not, i have no idea. I just know that speakpigeon does not only work with true premises.
Atla wrote:
Sat Jan 26, 2019 3:11 pm
You however pull "universal knowledge truths" out of your backside, and you think they are coming from God/the universe/whatever.
If that is what you think and believe, then that is fair enough.

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