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Proof of Anything (Posted on 2003-12-13) Difficulty: 4 of 5
Here is a nice little paradox:

Statement S: If S is true then God exists
Logically, statement S must be either true or false.

1. Suppose S is false.

2. If S if false, then any statement that starts with "If S is true..." is true *(see note)

3. Specifically, the statement "If S is true then God exists" would be true

4. This is exactly what S says, so S would have to be true

5. This is in contradiction with 1., so S cannot be false.

6. Therefore S is true.

7. So the statement "If S is true then God exists" is true.

8. By modus ponens, since S is indeed true, then the second half of that statement is true.

9. God exists.

Note of course that you can make the same argument to prove that God doesn't exist, or anything else.
What, if anything, is wrong with this proof?

*Note: This is the part that I expect most people will comment on. It is one of the standard logical rules that if something, A, is true, you can say "If (~A) then..." and that will always be true. For instance, I could say "If George Washington is alive then the moon is made of cheese" and that would be considered true in natural logic.

See The Solution Submitted by Sam    
Rating: 3.6250 (8 votes)

Comments: ( Back to comment list | You must be logged in to post comments.)
re: | Comment 36 of 44 |
(In reply to by Benjamin J. Ladd)

You still don't get it. And the arrogance of your latest post is even more irritating than the first one.

You toss thousands of years of philosophy and reason aside and simply conclude that faith is somehow of greater meaning than logic.

Well, if you understood logic at all, you would recognize that the problem being discussed is only a syllogism and that the paradox can be resolved using only logic. It seems that you still actually believe that it is possible to logically proove something with a statement alone, as the original poster claims. If that were so, this post would not have been made in a forum where the object is to find and elucidate logical flaws in what is stated.
  Posted by donnmike on 2003-12-17 22:07:15

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