Deductive logic test

[Panopticon]

The only thing you'll need is a few minutes. I got 15/15 on both.

http://www.think-logically.co.uk/lt.htm

http://www.think-logically.co.uk/lt2.htm

PS. I can help if necessary.

[Dominika]

13/15
14/15

[Jonik]

Please, give the very clear logical answer for this question (actually this question apply for computer programmer and only one version of answer should be right):
HOW PUT GIRAFFE TO REFRIGERATOR ?

[Prisoner Of Ice]

Please, give the very clear logical answer for this question (actually this question apply for computer programmer and only one version of answer should be right):
HOW PUT GIRAFFE TO REFRIGERATOR ?

int giraffe = 1;
int refrigerator = 0;

refrigerator = giraffe;

[Jonik]

int giraffe = 1;
int refrigerator = 0;

refrigerator = giraffe;

The real answer will be understand EVERYONE. I don't understand yours, sorry. But question still mostly for computer programmer behavior.

[armenianbodyhair]

Got 14 on the first one.

[Stefan]

Got a 14, didn't get the question about the 500 men and 500 women correct because I was too lazy to read it carefully. ;)

[Jonik]

int giraffe = 1;
int refrigerator = 0;

refrigerator = giraffe;

The Answer is:
1. Open the door
2. Put giraffe to refrigerator
3. Close the door

[larali]

13/15- first test
13/15 second test

Second test was fun :D

[Mortimer]

13
10

[Sblast]

I scored 15 (100%) on the first test. I gambled was testing with regard to rigor instead of just messing around with trick questions [meaning suppressed premises are a fair game]. Apparently I gambled correctly.
I scored 15 (100%) on the second test. Replacing the order of premises in 13, I didn't have to construct a single truth table through out the tests.

What's exactly the point in posting this to people who didn't study formal logic? It's fun, tho logic isn't intuitive and the tests are not exactly the hardest after a short course/introduction :).

"a) Whatever goes up must go down.
b) The train robbers are up before the beak.
Conclusion
Therefore the train robbers will be sure to go down." :lol:

Here's one for you:

The moon is made out of cheese and isn't made out of cheese.
All cheese is Roquefort cheese.
The moon is made out of cheese.
Therefor, Roquefort cheese is moon cheese.

[Herr Abubu]

15/15 on both.

[Mortimer]

Here's one for you:

The moon is made out of cheese and isn't made out of cheese.
All cheese is Roquefort cheese.
The moon is made out of cheese.
Therefor, Roquefort cheese is moon cheese.

valid

[Herr Abubu]

Invalid. First premise contradicts itself, and premise 2 and 3 implies that moon cheese/the moon is Roquefort cheese, not the other way around.

[Mortimer]

Invalid. First premise is contradicts itself, and from 2 and 3 implies that moon cheese is Roquefort cheese, not the other way around.

yes thats true

[Mortimer]

but if moon cheese is roquefort cheese, isnt roquefort cheese mooncheese?

[Mortimer]

also that there is moon cheese is not fitting, it should be moon is made out of roquefort cheese because all cheese is roquefort cheese. that roquefort cheese is moon cheese makes no sense in this context

[Mortimer]

i think i got it now, roquefort cheese is moon cheese is valid as in the moon is made out of roquefort cheese the cheese in the moon is roquefort cheese.

[Sblast]

Invalid. First premise contradicts itself, and premise 2 and 3 implies that moon cheese/the moon is Roquefort cheese, not the other way around.

Given the first premise is a part of the argument, the argument is valid. An argument is valid iff it is not possible for the conclusion to be false if the premises are true. It's impossible for the premises to be true when a contradiction is a premise (since it's always false) - there's no possibility that the premises are true and conclusion false - hence, the argument is valid. It's known as the principle of explosion.


valid

:thumb001:

[Herr Abubu]

Given the first premise is a part of the argument, the argument is valid. An argument is valid iff it is not possible for the conclusion to be false if the premises are true. It's impossible for the premises to be true when a contradiction is a premise (since it's always false) - there's no possibility that the premises are true and conclusion false - hence, the argument is valid. It's known as the principle of explosion.



:thumb001:

So if I understood correctly, if the first premise is a contradiction -i.e., something is and it is not simultaneously - then anything goes, basically? Both are true, so you can conclude what follows from either is or is not? But isn't the conclusion still invalid since all chese is Roquefort cheese although all Roquefort cheese isn't moon cheese? And doesn't this go against the law of noncontradiction, that A cannot be both A and not A at the same time?

[Sblast]

So if I understood correctly, if the first premise is a contradiction -i.e., something is and it is not simultaneously - then anything goes, basically? Both are true, so you can conclude what follows from either is or is not? But isn't the conclusion still invalid since all chese is Roquefort cheese although all Roquefort cheese isn't moon cheese? And doesn't this go against the law of noncontradiction, that A cannot be both A and not A at the same time?

Yeah, I put it confusingly, without that premise it would be invalid - but it's a premise in the argument regardless - which is always false.
Its falsehood is an implication of the law of noncontradiction (A cannot be both A and not A at the same time). Yes, anything follows, which makes it quite useless and a good reason to introduce the criteria of soundness.

[Herr Abubu]

Yeah, I put it confusingly, without that premise it would be invalid - but it's a premise in the argument regardless - which is always false.
Its falsehood is an implication of the law of noncontradiction (A cannot be both A and not A at the same time). Yes, anything follows, which makes it quite useless and a good reason to introduce the criteria of soundness.

Ok, I think I've understood it now. Quite counterintuitive at first.

[Mortimer]

Given the first premise is a part of the argument, the argument is valid. An argument is valid iff it is not possible for the conclusion to be false if the premises are true. It's impossible for the premises to be true when a contradiction is a premise (since it's always false) - there's no possibility that the premises are true and conclusion false - hence, the argument is valid. It's known as the principle of explosion.



:thumb001:

i didnt thought about it like that. i excluded the first sentence because it is a contradiction so i thought it eliminates itself, i took that all cheese is roquefort cheese and that roquefort cheese is moon cheese since all cheese is roquefort cheese therefore the cheese in the moon must be roquefort. but it is interesting. i think you need to study it and learn more about it to know the various techniques

[Lena]

http://img22.imageshack.us/img22/4478/hldo.png

btw, seen much complicated tests, maybe someone could find them and post links here.