If A is B, but B is A and C, then assuming that A is not C is it possible that B = C, or is it certain that B = C (assuming obviously that A = A, B = B etc)
[quote]nice try but if A is equal to C then A cannot not be equal to C
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it can, if A, B and C are all 0.
If A is B, but B is A and C, then assuming that A is not C is it possible that B = C, or is it certain that B = C (assuming obviously that A = A, B = B etc)
If 0 is 0, but 0 is 0 and 0, then assuming that 0 is not 0 is it possible that 0 = 0, or is it certain that 0 = 0 (assuming obviously that 0 = 0, 0 = 0 etc)
clearly the assumption is wrong, because 0 is always 0
If A is B, but B is A and C, then assuming that A is not C is it possible that B = C, or is it certain that B = C (assuming obviously that A = A, B = B etc)
If 0 is 0, but 0 is 0 and 0, then assuming that 0 is not 0 is it possible that 0 = 0, or is it certain that 0 = 0 (assuming obviously that 0 = 0, 0 = 0 etc)
clearly the assumption is wrong, because 0 is always 0
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You need to revise your axoims
This is a Java forum, not some place for semi-elevated enlightened wannabe philosophers. :-*
And Kev, Option 2 is not ‘an option’ as he didn’t seem to mean + but =.
In that case the set of conditions is just wrong, instead of a paradox.
It’s like saying, if 13 = 14, and we assume they are equal, they cannot be equal.
That’s all you need to show that your antecedent is a contradiction. Convert this into first-order logic, and it’s simply a conjunction of equalities. I’ll use a plus for conjunction since this board doesn’t seem to support LaTeX’s \wedge.
(A=B) + (B=A) + (B=C) + (A!=C) -> [anytthing]
The left hand side is clearly a contradiction:
A=B + B=C <=> A=C
which yields A=C + A!=C in the antecedent.
Now, once you have a contradiction as the antecedent of a material impliciation, you can imply anything at all. Remember the truth table for material implication:
A B A->B
T T T
T F F
F T T
F F T
Hence, the consequent is true. The general scientific rule here is that if your assumptions contain a contradiction, you can prove absolutely anything. Insert discussion of evolution vs. creationism here.
The author is probably trying to be clever by inserting an ambiguous “or” in the consequent. If this is inclusive, then we’re done. If it is exclusive, then only one of the components of the disjunction can be true. However, once we’ve shown a contradiction in the antecedent, pragmatic philosophers wouldn’t care.
I wouldn’t call it armchair philosophy: I would call it a mean homework assignment from a discrete maths course.