(take a moment to think about it).
(continuation below)
While this is a complete blasphemy, it illustrates an important point.
Sometimes, subtle switches between induction and deduction are used in
a mystical manner, either deliberatly or while being careless.
In any case, if you want to learn more about the mathematical and
logical nature of many jokes, I can wholeheartedly recommend to read
John Allen Paulos' book "Mathematics and Humor".
Best regards,
Shlomi Fish
Shlomi Fish wrote:
> If:
> 1. A is A.
> 2. A is not not-A.
> does it imply that:
> 1. B is B.
> 2. B is not not-B
> ?
>
> (take a moment to think about it).
> (continuation below)
Shlomi, A occurs as a bound variable to a quantifier
that is implied but not written. Substitution the bound
variable A with the bound variable B does not change
anything.
Have I missed something?
Bob Kolker
Paulos is brilliant. His books on "Innumeracy" were among the most
overlooked and important social commentary in recent history. And what a
fascinating, absorbing author he is.
Yes, I have read "Innumeracy", which is a very good book. The book
"Whence Numeracy" is also very nice, especially for people who are not
professional mathematicians.
Regards,
Shlomi Fish
I know one should not explain jokes, but I hope you'll understand:
How do you know that what is true for A is also true for B? ;-)
Regards,
Shlomi Fish
> Bob Kolker
Shlomi Fish wrote:
>
> How do you know that what is true for A is also true for B? ;-)
A occurs as a bound variable to an implied universal quantifier.
What the first statement says is : For ALL A, A is A and A is not not A
So plugging in B where A occurs does not change a thing.
If the name of a particular entity were placed in the statement,
you might have a point. BTW, what is funny about this?
Bob Kolker
Yeah--I think that's why he put the smiley.
> If the name of a particular entity were placed in the statement,
> you might have a point. BTW, what is funny about this?
This reminds me of another joke. An algebra teacher is discussing a problem
with a student. The teacher says, "Now, suppose x is the speed at which the
train is traveling ..." And the student says, "But teacher, suppose x isn't
the speed at which the train is traveling?"
That's the whole point. One of the ways to interpret "A is A and A is
not not-A", is "for all", and another one is "For a particular A...".
> So plugging in B where A occurs does not change a thing.
>
> If the name of a particular entity were placed in the statement,
> you might have a point. BTW, what is funny about this?
>
I hope now you understand.
Very nice. I'll add it to one of my fortune files. In any case, if you
wish to
read some of my other humurous bits (or my more lengthy stories) you
can consult my homepage:
http://t2.technion.ac.il/~shlomif/
Almost everything is available in English.
Here's one of my favourite bits I came up with:
I don't believe in fairies. Oops! A fairy died.
I don't believe in fairies. Oops! Another fairy died.
I figured it was something a young Clarissa Darling would say... (no
pun intended)
Regards,
Shlomi Fish
> If:
> 1. A is A.
> 2. A is not not-A.
> does it imply that:
> 1. B is B.
> 2. B is not not-B
A=B. Whatever symbol used, things are what they are.
--
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Reason is the basic method of human survival. AYN RAND
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Radically systematic radical metaphysics: Existence 2
http://home.att.net/~sdgross
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Stephen Grossman Fairhaven, MA, USA sdg...@att.net
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