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Logic and intuition
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Wén Shào
Apr 2, 2012, 5:32:10 AM4/2/12
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Hi guys,
I recently heard something interesting from my friend regarding an
email regarding a fire drill from our admin. The following comments
are given by John @ ANU (presumably you didn't get John's email):
==================== John's email ====================
The mail from Vanessa yesterday struck me as logically
interesting. It said:
> The College’s buildings are due hold fire drills within the next two
months.
> Obviously the point of a drill is that you do not know when it will
happen
> however that does not mean that you should not be prepared.
I suppose "within the next two months" means before the end of June.
Now obviously the drill cannot take place on June 30, as then we would
know ahead of time (on June 29 evening) when it was going to happen.
So it will happen by June 29 at the latest. But that means it cannot
be scheduled for June 29, or we could work out on June 28... etc.
Repeating this reasoning often enough, we arrive at the conclusion
that it cannot be scheduled at all. So Vanessa's email is false.
Nonetheless, when the drill takes place on (say) 23 April, it's a
surprise to everyone, so Vanessa's email will turn out true after all.
Anyone good at epistemic logic and paradoxes?
==================== End of John's email ================
Do you have any thought about this? The conclusion that the fire drill
cannot be scheduled at all seems true and the argument itself is sound
and makes complete sense to me, however, it is also true that when the
drill happens on a particular day, we will all be surprised (we didn't
know in advance). Can you find any flaws in his argument?
Cheers,
Wén
I recently heard something interesting from my friend regarding an
email regarding a fire drill from our admin. The following comments
are given by John @ ANU (presumably you didn't get John's email):
==================== John's email ====================
The mail from Vanessa yesterday struck me as logically
interesting. It said:
> The College’s buildings are due hold fire drills within the next two
months.
> Obviously the point of a drill is that you do not know when it will
happen
> however that does not mean that you should not be prepared.
I suppose "within the next two months" means before the end of June.
Now obviously the drill cannot take place on June 30, as then we would
know ahead of time (on June 29 evening) when it was going to happen.
So it will happen by June 29 at the latest. But that means it cannot
be scheduled for June 29, or we could work out on June 28... etc.
Repeating this reasoning often enough, we arrive at the conclusion
that it cannot be scheduled at all. So Vanessa's email is false.
Nonetheless, when the drill takes place on (say) 23 April, it's a
surprise to everyone, so Vanessa's email will turn out true after all.
Anyone good at epistemic logic and paradoxes?
==================== End of John's email ================
Do you have any thought about this? The conclusion that the fire drill
cannot be scheduled at all seems true and the argument itself is sound
and makes complete sense to me, however, it is also true that when the
drill happens on a particular day, we will all be surprised (we didn't
know in advance). Can you find any flaws in his argument?
Cheers,
Wén
Madhur Varshney
Jun 26, 2012, 2:15:47 AM6/26/12
to
Though it is desirable that the drill be a surprise, it is not a "given" fact that can be assumed as a logical certainty. Hence the logic as applied is not applicable.
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