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# Difference between revisions of "Sudoku/Controversies/Uniqueness/Reddit"

What I see happening in this discussion is that a user was affronted personally and began, as a normal human response, to rationalize his positions, inventing or gathering arguments that are weak, and continuing to make assumptions about the topic and about what others were writing, that are not shared.

When we are offended, in general, our thinking goes awry, being dominated by survival reactions, and this is all stuff that I spent years studying and in training over. None of this makes any position "right" or "wrong," which are judgments, not actually facts. To move beyond this requires some caution and care. To really understand this may require reading the entire thread, which was not about persons, but about Sudoku and a particular claimed uniqueness pattern.

This turned into a replay of common arguments about uniqueness, I've seen in many places.

from sotolf2 via [ /r/sudoku] Jan 15 2020 15:55 GMT - quorting u/Abdlomax (Abd on this wiki) Abd's original comment is in italics without indent. Responses here will be in indented italic.

Who said that uniqueness is "invalid"? Certainly not me! Rather, uniqueness is based on an assumption that was not stated when Sudoku were first formally defined and published. It was still assumed, by both authors and solvers. Some books add it as an afterthought.

So where is this authorative definition? I certainly haven't seen it anywhere, and I don't really belive one exists, if we are going to treat sudoku as a logic puzzle though it will have to have a logically deducable solution, something that is not possible if there are multiple solutions.

Can we agree that sudoku solving is logic?

Not if a puzzle has multiple solutions, if it does it will be logically unsolveable.

Any answer that satisfies the rules of of sudoku is "valid," so it is a solution. Claiming that guessing is required is not clear thinking.

I don't think I did, I might have though, but you can't logically deduce a solution if there are two valid solutions, unless you have some extra rules.

But then difficult puzzles began to be developed, considered "unsolvable without guessing." (And the language there was way cuckoo.)

I 100% agree with you in that.

Sotolf2, you are creating a straw man argument, that someone claimed uniqueness is "invalid," when what is being said is that uniqueness is based on an additional assumption, not formally stated originally.

Again, until this "original" document of sudoku holiness is somewhere I can access it and see it I might agree with you, but I will assume that a sudoku puzzle should be logically deducible, or it is no longer a logic puzzle.

What I did, among other things, was to prove that the assumption of uniqueness was invalid for this puzzle. That is most clearly accomplished by showing at least two.

This is what I personally classify as a bad puzzle, just as we would classify "10 They dog ago go buy days" as a bad English sentence even though it's kind of understandable it's still not a good sentence.

u/the_gr8_n8 is solid here

How so, he's assuming some kind of "Ground rules" that he still denies to supply. Also he's using rude language for no reason at all.

Saying that I "hate" something is not a claim that it's wrong or bad or defective by some objective standard. It's simply how I feel

"Saying that I hate muslims is not Saying that I "hate" something is not a claim that it's wrong or bad or defective by some objective standard. It's simply how I feel"

Phrased like that don't you see that this doesn't really hold water?

Obviously, that "hatred" is weak, just a feeling that arises. I am also eager to get the candidate lists done, making them complete, and, overall, pleasure at that dominates.

Dislike and hate is not the same.

Yes, that a sudoku has any solution is also "up in the air," meaning unproven until the solution has been demonstrated by logic from the basics. Yet I and everyone else makes that assumption, because no-solution puzzles are even rarer than multiple-solution ones.

Yeah, so why is it okay to assume that the puzzle has any solutions but not that it has a single one?

Because speed is not my goal (at all), I prefer to use uniqueness but not to depend on it. That's a preference, not some critique of uniqueness.

Yeah, I see nothing wrong about that at all, we all have preferences likes and dislikes, what I have a problem with is to claim others make "no good" assumptions, when it's a neccessity for what we all enjoy in a puzzle, that it's logically solvable.

It has happened here a number of times that if I pointed out that using uniqueness as if proof.

I can agree that it will be wrong to use it as a proof, as it isn't really, as a shortcut to solving, like colouring or fishes or anything I don't see how it's any less valid than anything else.

argument from authority

An arguement from authority would be to claim that someone makes an assumption based on something like someone said, like "It's not part of the original definition of sudoku" And I'm not the one claiming that.

For me guessing would be to go with something before you have a convincing reason to go for it, which I don't think colouring is, colouring is not guessing, and neither is uniqueness. Not that I think guessing would not be a valid way to get to a solution, it's just not one that I like to use myself.

I just get annoyed when someone claims I make assumptions that "Are not valid" and they themselves aren't able to make at least some reasoning without acting out and being rude like was the case here.

So I suggest the syllogisms

A: Sudoku is a logical puzzle B: All logical puzzle has to be solvable by logic C: Sudoku has to be solveable by logic

A: Sudoku has to be solveable by logic B: A puzzle with multiple solutions aren't solveable by logic C: Sudoku with multiple solutions are not valid

A: A valid sudoku has one solution B: A situation with multiple solutions is not something allowed in a valid sudoku C: uniqueness is a valid technique

So I hope that makes it clear that I'm not arguing from authority, just from the assumptions that we both agreed upon.