How to test someone's logic skills?

The idea

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What's a good way to test someone's logic skills? The following approach occurred to me.

Provide a series of alleged proofs, half of which are valid and half of which are invalid. The valid proofs will be as unpersuasive as possible and the invalid proofs will be as persuasive as possible. The person will be required to specify, for each alleged proof, whether it is valid or invalid.

What are the advantages and disadvantages of this approach?

What other approaches might one use?
 
Bodhi Dharma Zen said:
Are you talking about syllogisms?
I suppose one could start with syllogisms, but I'm talking about actual reasoning that people actually use when they are arguing with each other. I presume that some of it is valid.
 
Can anyone demonstrate to me that logic generates right answers. Not true answers, mind you.
Right answers.

I have a dark suspicion that there are few real-world situations more complex than whether a switch is open or shut, which are actually amenable to logical analysis.

For example-
Which is better, a dog or a camera?
What's so bad about being over forty?
Why me?
 
And, "Of what use is a philosopher, unless he can get that football off the roof from behind the chimney?"
 
Jeff Corey said:
And, "Of what use is a philosopher, unless he can get that football off the roof from behind the chimney?"

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:dl:
 
The idea said:
What's a good way to test someone's logic skills? The following approach occurred to me.

Provide a series of alleged proofs, half of which are valid and half of which are invalid. The valid proofs will be as unpersuasive as possible and the invalid proofs will be as persuasive as possible. The person will be required to specify, for each alleged proof, whether it is valid or invalid.

What are the advantages and disadvantages of this approach?

What other approaches might one use?

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Please give us one real life example. Thanx.
 
*I* know a test that will determine if you have high speed brain processing skills. Here is how: (Note, I am going to submit this idea to the Wisconsin Board of Education.)

Are you ready? Okay. Think fast. Whoever posts the answer here the fastest, wins. But also, be honest in saying about how fast it took you to come up with the answer.

Who would my grandfather's boy's son be, who has an uncle that is the married husband of my blood aunt, who is not my brother?
 
The idea said:
What's a good way to test someone's logic skills?

Hmm, I'd give them some mathematics problems, but without equations and etc. so it doesn't really look like a math problem.
 
Iamme said:
*I* know a test that will determine if you have high speed brain processing skills. Here is how: (Note, I am going to submit this idea to the Wisconsin Board of Education.)

Are you ready? Okay. Think fast. Whoever posts the answer here the fastest, wins. But also, be honest in saying about how fast it took you to come up with the answer.

Who would my grandfather's boy's son be, who has an uncle that is the married husband of my blood aunt, who is not my brother?
Depending upon the state you live in, it could be an lamb, named Arthur.
 
Soapy Sam said:
I have a dark suspicion that there are few real-world situations more complex than whether a switch is open or shut, which are actually amenable to logical analysis.

Well, logic is useful in cases where you can abstract the problem suitably. (That is, you can take in all relevant information and still have the theory small enough to allow you reason about it.)

One real-world example where I would use logic would be creating a seating arragement for a largish formal dinner (say, about 100 participants). A nice seating arrangement has the property that everybody has at least a couple of friends in immediate vicinity, sits opposite his or her avec, men and women alternate in such a way that a woman sits in the rightmost seat of the table (to the extent permitted by numbers of men and women), persons who dislike each other are seated far apart, etc.
 
The idea said:
I suppose one could start with syllogisms,

Well, one could if one likes to feel pain. (If one was a true masochist he or she would start with Hilbert's axioms or some equivalent construct). It is true that syllogisms were the best way to apply logic for about 2000 years. However, that also holds for Roman numerals (and equivalent systems) and mathematics but nobody thinks that they would be a suitable starting point for mathematics anymore.

I would suggest using some puzzles or Raymond Smullyan, perhaps from books What is the name of this book? or The Lady and the Tiger. His puzzles have the nice property that solving them needs progressively more logical abilities. Almost everybody can solve the first few ones but some the advanced ones are really devious. I have to admit that I couldn't solve the one about the "universal question" that can be used to solve any puzzle that involves asking "yes/no" questions in an optimal number of questions.
 
To: The Idea

You ask a paradoxical question.

If you need to ask for good tests, it suggests you may not have the requisite logic skills to tell a good answer to your question from a bad one.

But if you have such skills, why aren't you able to already see what a good test would be?

How would you resolve this paradox?

Bill
 
Jeff, your lamb/Arthur thing flew over me like a crow in flight. Explain. ;)
 
LW said:
Well, one could if one likes to feel pain. (If one was a true masochist he or she would start with Hilbert's axioms or some equivalent construct). It is true that syllogisms were the best way to apply logic for about 2000 years. However, that also holds for Roman numerals (and equivalent systems) and mathematics but nobody thinks that they would be a suitable starting point for mathematics anymore.

I would suggest using some puzzles or Raymond Smullyan, perhaps from books What is the name of this book? or The Lady and the Tiger. His puzzles have the nice property that solving them needs progressively more logical abilities. Almost everybody can solve the first few ones but some the advanced ones are really devious. I have to admit that I couldn't solve the one about the "universal question" that can be used to solve any puzzle that involves asking "yes/no" questions in an optimal number of questions.

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LW, some dryer, furnace, and other appliance manufacturers use the Yes/no 'puzzle" thing, to help guide you through a quick troubleshooting procedure. This works very nicely.

Example: Power at switch? Yes/no

Yes? Power at door swirtch? Yes/no

No? Bad door switch. Replace.

Yes?...and so it goes. These things are always in easy to read large print and only take up one page and cover everything in just a few short yes/no questions. They cover more ground than you think would be possible by the questions they ask.
 
What I hate are the instructions written by Kumar.
"For instructions to format your chip, see page 29.
Page 29, "First, format your chip.."
 
From LW:
the one about the "universal question" that can be used to solve any puzzle that involves asking "yes/no" questions in an optimal number of questions[
I have several of Smullyan’s books, but don’t recall that problem. What is it, please? Perhaps post it in Puzzles forum?
 
Lucky said:
I have several of Smullyan’s books, but don’t recall that problem. What is it, please? Perhaps post it in Puzzles forum?

For each liar-truthteller puzzle domains there is possible to form a statement X such that you can combine X with your yes/no question to force correct answers. (Not to spoil too much, I'll use 'X + Q' to denote combining the questions). For example, if you had the standard case of two doors and two guards one of whom lies, you could form the question 'X + "Is the left door safe?"' and the answer would be "Yes" if it was safe and "No" if it wasn't, no matter which guard you asked. (In fact, in this case you wouldn't even know whether the guard lied or not).

Of course, the precise formulation of 'X' depends on the domain, but there is a systematic way of constructing it. The particular problem domain in What is the name of this book? was Transylvania where all people are either humans or vampires and either sane or insane. The idea is that humans tell what they think is the truth while vampires lie, but insane people believe in falsehoods. So, the groups are:

- sane human: tells the truth
- insane human: lies but believes that he tells the truth
- sane vampire: lies
- insane vampire: tells the truth but believes that he lies.
 
Soapy Sam said:
Can anyone demonstrate to me that logic generates right answers. Not true answers, mind you.
Right answers.

I have a dark suspicion that there are few real-world situations more complex than whether a switch is open or shut, which are actually amenable to logical analysis.

For example-
...
Why me?

Why not?!

That was easy. :D
 

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