jimmysnyder said:Perhaps you missed my post #30 in this thread.
Not at all. But I was referring more to post #36. Let's look at them both, then.
jimmysnyder said:Actually, I expect the 98% thing is true. No one in this thread got the right answer. A second thread with the same puzzle appeared in Physics Forums about a year or so ago with the correct answer which I repeat below:
No one has a fish. The only time a fish is mentioned is in the question. That is the 'Einstein' angle. Einstein's special theory requires you to abandon the unjustifiable assumption of absolute space and time, just as this puzzle requires you to abandon the unjustifiable assumption that one of the pets is a fish.
You are correct that as a straightforward logic puzzle, this one is not particularly difficult. That, together with the "98% thing" is in itself a clue.
This post references almost no logic whatsoever with regard to the puzzle at hand. It instead references the "Einstein angle" which is a "hint" at a possible interpretation of the style of the method of obtaining a solution. It says nothing about the solution itself and how to obtain said solution uniquely and verifiably using such a hint.
It does reference logic insofar as it addresses the fact that "The only time a fish is mentioned is in the question." Which does point out the flaw in the wording of the problem, hence pointing at the ambiguity.
But your post #36 is by far a better attempt to explain your position logically. As I've pointed out, it's not entirely based in logic, it's partially based in experience which is unverifiable, and hence cannot be accepted as a solution. But for reference's sake, post #36:
jimmysnyder said:That's not so. If it were, then the problem would indeed be unsolvable. Therefore, there is no fish.
To sum up of the three possibilies:
1) Could be a fish or could be no fish: Wrong, ambiguous, violating the solvability clue
2) Is a fish: Wrong, too easy, violating the 98% clue.
3) Is no fish: Right, satisfies all clues.
Now, you've analyzed the possibilities totally correctly:
1) A fish may or may not exist, if it exists, the German owns it
2) The German owns the fish
3) There is no fish
And, you've already stated that you are unwilling to accept the ambiguity of #1 as a solution, which is totally within your rights, although my personal and also unverifiable feeling on that would be to allow it.
And you're correct by allowing #3, as it does not explicitly violate any clues explained in the puzzle.
But the sticky bit is that you're claiming that #2 is not a valid solution, but you don't give a verifiable, logical explanation as to why. You claim "too easy", which is an arbitrary judgement call on your part, based on your experience with people's abilities to solve these sorts of problems.
Daveb's solution was a valid interpretation, if, as both you and he agree, you don't want to allow any ambiguity in the solution. But there's really only one way to approach the problem after that assumption is made. Either #2 or #3 is correct, but not both, and there can be no ambiguity.
But to make such a conclusion, we have to look at the question. "Who owns the fish?" Now, if the question were instead "Who owns a fish?", the "a" is a nondescript object, allowing the potential for no fish to actually exist. But by specifying "THE fish", there's a definite article, which, if you're a lawyer, you would probably agree implies (if not explicitly defines) the existance of a fish. Hence, the fish MUST exist, and it must be owned by the German.