In most board games, the default assumption is

You cannot do something unless the rules say you can.

That might seem obvious, but in another universe the default assumption could be

You can do something unless the rules say you can't.

When I tried to explain this in an answer, it received negative attention. I intended to explain, but perhaps did not communicate well, that if the rules do not allow you can continue playing, you cannot continue playing.

This approach to answering "Can I [...]?" questions places the onus back on the asker to find a rule that allows it. The alternative would be to actually prove that no rule allows it. Proving that no relevant rule exists would be like attempting to prove that Russell's teapot does not exist, but on a smaller scale.

One of the commenters believed that shifting the burden of proof to the asker was equivalent to not addressing the question at all. That is not true. Answering the question and proving that your answer is correct are two different things. I did answer the question.

I understand that my answer stood next to another that quoted the official FAQ. However, FAQs are simply a collection of questions that are frequently asked. The FAQ didn't even mention why the answer was correct. I decided that "Because the FAQ says so." wasn't good enough, and wanted to post a more logical answer alongside it. "Because the FAQ says so." is simply a false pretense of proof.

Why did it receive such negative attention? Was the answer logically flawed? Could I improve the wording such that it may be better received next time I use this approach?

Note: If a rule did exist which stated that you cannot do something, that would clearly be preferable. I only want to discuss the case where there is no such rule.

  • 4
    For what it's worth, I'm not sure that your title is the most constructive question to ask. The real question is why your answer got downvotes, and why people seemed to have a problem with it. I wouldn't assume that those things happened because your answer contained logic.
    – Cascabel
    Jan 14, 2015 at 21:34
  • @Jefromi This is why I hate linking to actual examples. People spend seven paragraphs talking about the specific example, and pay almost no attention to the concept. I only want to know if some questions are better answered by shifting the burden of proof back to the author. Murgtroid99 believes that every question has an answer straight out of the rulebook. I disagree with his answer, but at least half of his answer directly addresses the question.
    – Rainbolt
    Jan 14, 2015 at 22:07
  • 2
    My answer (and murgatroid99's) are trying to say that the reason you saw a negative reaction was details of the specific example. In general, logic is not treated harshly. You yourself asked in the body of your question "Why did it receive such negative attention? Was the answer logically flawed? Could I improve the wording such that it may be better received next time I use this approach?" and our answers attempted to address this. There's no point in trying to address the concept of "why is logic treated so harshly" - it isn't.
    – Cascabel
    Jan 14, 2015 at 22:13
  • One thing to remember is that rule books would be much longer and harder to deal with if they had to include every edge case of what you can and can't do.
    – Joe W
    Jan 15, 2015 at 0:02
  • @JoeW Agreed. Which is why rulebooks generally state what you can do, and assume that you can't do everything else. It's almost as though your comment was the point of my entire post.
    – Rainbolt
    Jan 15, 2015 at 0:19
  • 1
    @JoeW I think everyone here agrees about that. The issue is why Rainbolt's post received negative attention, which likely has to do with the actual content of the answer, which was fairly different from your statement.
    – Cascabel
    Jan 15, 2015 at 0:30
  • 1
    I don't think this has anything to do with logic. The original answer is one of the most smug, implicitly self-congratulatory posts I've read on SE. Walking the OP through axiomatic set theory (or whatever) is worse than worthless; just say what the rule/ruling is, slap a link to the rulebook up there, and call it a day FFS! Jan 17, 2015 at 1:38
  • @TheChaz2.0 I don't think that pointing to an absence of rules is "self-congratulatory". I just don't know how else to explain that "What you are trying to do is not covered by rules." and that anything not covered by the rules is inherently illegal. Another user did find a relevant rule after the fact. When I answered, Phil Summers had not yet posted his finding, and I found the FAQ quote to be unconvincing. It basically said that "It works this way because the FAQ interpreted it that way."
    – Rainbolt
    Jan 20, 2015 at 14:14
  • "... is not covered by the rules" - except you are making a ruling, using some cobbled-together syllogisms (and condescending tone of voice). I appreciate the robotic approach as much as the next math hobbyist, but that just doesn't fly with most people. Jan 20, 2015 at 17:04
  • @TheChaz2.0 Are you suggesting that "say what the rule/ruling is, slap a link to the rulebook up there, and call it a day" is less robotic? When someone asks a trivial question about Magic, what drives someone to write an answer that math hobbyists find interesting? I'm not sure where you found the "condescending tone of voice". I was careful to avoid saying anything negative about the question or its author. If arriving at an obvious conclusion is an inherently negative act, then I suppose I was being condescending.
    – Rainbolt
    Jan 20, 2015 at 17:31

3 Answers 3


I'll start with the current/final form of the answer. I know the longer argument has been removed, but I'm not sure whether you got your downvotes on this form or the old one.

I think that it's not necessarily logic that's being treated harshly here. It does also matter how you say things. Although I'm sure you didn't mean it this way, your answer in its final form might come across to some people as being a bit derisive: it sounds like you're saying to the OP, "you're just making up rules". Perhaps you could present your proof without saying "made up rules" - for example, you could say "there is nothing in the rules about having to announce your score."

Beyond that, I think that you haven't necessarily presented the argument itself in the most convincing way. You've just asserted that this isn't in the rules. You've left it as an exercise to the reader to go through the rules and make sure that the rules really don't say anything about this. You could instead just quote the most relevant passage of the rules:

If you have 10 or more victory points during your turn the game ends and you are the winner! If you reach 10 points when it is not your turn, the game continues until any player (including you) has 10 points on his turn.

and then point out that it doesn't say anything about revealing, simply that you must have the rules. You could also consider quoting the section about Victory Point Cards, though admittedly it says "You may only reveal them...to win the game" and is not really clear that you must do so.

In any case, it doesn't make as much sense to readers if you instead present a logical argument about made-up rules that appears very isolated from the rules.

As for the original form of the answer, I think that your attempt at a logical proof unfortunately was unnecessary and confused the point. Keep in mind, the OP's question boils down to "I know I win at 10 points. Is that 10 points including things that are in my secret hand, or do I not actually have those points until I show them to people?"

In your answer's original phrasing, you used as one of your assumptions "You have ten points", and interpreted the rules to say that you have the points whether or not you've revealed them. ("Assumption 1 is simply true. You have 10 points. This is an observable fact.") That interpretation is the core answer to the OP's question. Once you make that point, you don't really need to prove that it results in winning and ending the game; everyone was fully aware that the game ends when someone reaches 10 points.

As a side note, there was no need to formulate the proof as a proof by contradiction. You danced around it, but you essentially said that assumption 1 (you have ten points) plus assumption 3 (if you have ten points you win) plus assumption 4 (the game ends when someone wins) implies that the game has ended (assumption 2). Nice, simple, direct logic.

  • Let's be clear: you made two different transformations to my proof. 1) You inlined the entire proof. 2) You wrote a direct proof rather than a proof by contradiction. Number 1 saved you a ton of lines. Number 2 saved you one line at best. Anyone can write a summary and say "Look how short I made your entire argument!" Literally the only difference between a direct proof and a proof by contradiction is "Assume true. Arrive at trainwreck, so assumption must be false." and "Assume false. Arrive at logical." My choice of proof had little to do with the clarity of the answer.
    – Rainbolt
    Jan 14, 2015 at 22:00
  • 2
    @Rainbolt I'm sorry, but I disagree. "A implies B; A, therefore B" is far clearer than "A implies B; A, assume not B, but B is true, contradiction, therefore B". In any case, I did call that a side note. The main point is that what you proved wasn't the core thing that needed to be answered (is revealing optional/are secret points still points).
    – Cascabel
    Jan 14, 2015 at 22:11
  • Re: "is revealing optional" I'd argue that no rule forces you to reveal, and that an omnipotent arbitrator could simply declare that you won without revealing. My answer attempts to disassociate winning and revealing. In other words, winning does not depend upon revealing. The two are totally unrelated as far as that question is concerned.
    – Rainbolt
    Jan 14, 2015 at 22:57
  • @Rainbolt The way you've phrased things is another way of saying "revealing isn't optional": you're saying that you win whether or not you reveal, i.e. you do not have the option of not revealing. Your proof states/assumes this to be true by making "you have ten points (and therefore win)" equivalent to "you have ten points, some of which are/were secret (and therefore win)" - and that's the core of the answer, not the proof that this subsequently causes you to win the game.
    – Cascabel
    Jan 14, 2015 at 23:07
  • "You have ten points, some of which are/were secret (and therefore win (and therefore the game ends))" The first part in bold is totally irrelevant. The second part in bold was a glaring omission. The reason that the first part is totally irrelevant is that the game has already ended, you won, and you got 10 points. Would revealing change any of that? No. You know as well as I do that author's don't always ask the question that needs answering.
    – Rainbolt
    Jan 14, 2015 at 23:44
  • @Rainbolt The fact that the first part in bold is irrelevant is part of your answer. The OP didn't know whether it was; they thought that possibly the fact that they were secret meant that you didn't win until you actually revealed them, and thus he could possibly wait to win. Saying that it's irrelevant (and explaining why) is an answer to the question.
    – Cascabel
    Jan 14, 2015 at 23:49
  • That's the issue: I can't explain why it is irrelevant. The burden is on you to explain why it is relevant. And until you do, the default assumption should be that it isn't. I feel like a broken record. You need to read about absence of evidence. You simply can't use absence of evidence to demonstrate that evidence does not exist altogether. To explicitly write "revealing is irrelevant" in my answer would be a lie (and I'm a little sad that I slipped in my comment). I can only write "Nothing shows that it is relevant, so it probably isn't."
    – Rainbolt
    Jan 14, 2015 at 23:51
  • @Rainbolt So your answer should say something along those lines ("Because there's nothing in the rules that says X matters, it doesn't matter."), and indeed the final form of your answer does! Awesome. I'm just saying that the proof didn't add anything to that; if anything it confused the issue, and that's what garnered some negative reaction. But the final form is reasonable; it says what needs to be said. I think maybe you could've said it better (see the first half of my answer here) but it does say it.
    – Cascabel
    Jan 15, 2015 at 0:02

The primary flaw in your premise is that you seem to assume that a game rulebook is primarily a list of things that players are allowed to do, which implies that demonstrating that a player is not allowed to do something can require enumerating the rules. However, rule books are primarily definitional. If we look at the Magic: the Gathering rulebook (which I have the experience), the first five major headings define the parts of the game. The first one defines the fundamental concepts, and the next four give more detailed definitions for some of those concepts. Because these rules are definitions, they enumerate what relevant actions a player can take, and the player cannot take other actions by definition. If someone asks "Can I do X when I have priority?" the response is "Rule 116 defines priority. You can only do the things it lists." If they ask "Can I choose purple as a color for some effect?" you don't need to scour the rulebook to find a rule that allows it, you just need to quote the definition of color in rule 105.

There are a couple of issues here. First, the fact that your question was downvoted. For that, we have to consider the revision history, since people were voting before you edited to your current version. If we look at the original version of your answer, you had this "proof by contradiction" that had these assumptions:

  1. You have 10 points.
  2. The game has not ended yet.
  3. You win when you have 10 points.
    • This assumption is taken directly from the rules.
  4. The game ends when a player wins.
    • This assumption is taken directly from the rules.

The problem I see here is that according to the arguments you used, the rules quoted in points 3 and 4 (or even just point 3) are sufficient to conclude that if a player has 10 points, then the game is over. In other words, your argument is logically equivalent to ""According to [rule from point 3] and [rule from point 4], the game ends when any player has 10 points." Unless I am missing something major, that conclusion is also the conclusion of your answer. Everything besides those two rules is unnecessary to the argument and just makes it more convoluted. The strategy of using "proof by contradiction" was completely unnecessary and made the logic harder to follow.

I just want to make this clear: the argument you originally gave was bad because it had an unnecessary step (contradicting a made-up premise) and, for the conclusion you seemed to be "proving", two or three unnecessary premises.

The second issue is the more general one of people asking for rulings that may not exist. The fact that I mostly answer MTG questions probably biases my view of this, but in my experience the rules don't just allow you to do some things or disallow you from doing some things; they specify exactly what players can do. The point is that every situation should have a definitive ruling from the rules, and as I said in my previous paragraph, that seems to be the case for this question.

As a final note about FAQs: rules in games are not like rules in math or science, which must be discovered and/or proven. They are true because they are the rules of the game. Any official rulings therefore come from the highest possible authority and are therefore as true as the rules themselves.

  • The only way to write a proof by contradiction is to start with a premise that, upon failure to prove, will result in it's opposite being true. So I made one up. Are you saying that every proof by contradiction should start with something that isn't made up? If so, why do you think that?
    – Rainbolt
    Jan 14, 2015 at 18:11
  • Re: "they specify exactly what players can do" That's exactly what I said. Your fourth paragraph implies that our views differ on this topic, but they do not. What part of my meta question led you to believe that we do not agree on this issue?
    – Rainbolt
    Jan 14, 2015 at 18:14
  • Re first comment: I see that I did not explain myself clearly. What I was trying to say with my second paragraph was that proof by contradiction as a proof method was unnecessary. The argument you present in your original revision is logically equivalent to "According to [rule from point 3] and [rule from point 4], the game ends when any player has 10 points."
    – murgatroid99 Mod
    Jan 14, 2015 at 18:16
  • (Sorry for so many separate comments - the answer is kind of long.) Re: "Everything besides those two rules is unnecessary to the argument and just makes it more convoluted." The problem with the proof was that point 4 isn't actually written in the rules. I didn't like the fact that my proof relied on an assumption that I pulled out of thin air, so I removed it. It was a reasonable assumption, but it wasn't as set in stone as I wanted it to be. Also, a moderator found the entire proof to be overkill.
    – Rainbolt
    Jan 14, 2015 at 18:17
  • Re second comment: You say in the question "Proving that no relevant rule exists would be like attempting to prove that Russell's teapot does not exist, but on a smaller scale." I said in paragraph 4, last sentence, that "every situation should have a definitive ruling from the rules." If my statement is true, then there are no situations where "no relevant rule exists."
    – murgatroid99 Mod
    Jan 14, 2015 at 18:21
  • Having now explained yourself more clearly in the comments, can you edit your answer? Make it clear that issue #2 is not with the assumption or the conclusion that were made, but with the form of proof used.
    – Rainbolt
    Jan 14, 2015 at 18:21
  • Re third comment: I hope you can understand how quoting a rule that doesn't actually exist might be confusing. And you continued saying that it was from the rules through all revisions until you deleted your argument entirely. If you're looking for an answer to "was the answer logically flawed?" look no further than "one of the premises was made up."
    – murgatroid99 Mod
    Jan 14, 2015 at 18:25
  • Re fourth comment: I added a couple of sentences to try to clarify that.
    – murgatroid99 Mod
    Jan 14, 2015 at 18:27
  • That's just it. Your statement isn't true. "Every situation should have a definitive ruling from the rules" is a false statement, unless "the entire rulebook" counts as a definitive ruling. The rulings cover everything that you can do. What you can't do is a negative of that. Therefore, quoting a relevant rule for something you can't do would require quoting the entire rulebook. The exception is when a rule is written that explicitly states that you can't do something, but in this case, there was no such rule.
    – Rainbolt
    Jan 14, 2015 at 18:29
  • OK, if you think my statement isn't true, I don't understand "Your fourth paragraph implies that our views differ on this topic, but they do not." And I still disagree with your statement. MTG, for example, has a list (spread across a few rules) of everything you can do when you have priority. If someone asks "can I do X when I have priority?" the question is always answerable without "quoting the entire rulebook." Similarly with questions like "can I draw at the end of my turn?" or "can I cast spells while others are resolving?" There is always a definitive answer from the rules.
    – murgatroid99 Mod
    Jan 14, 2015 at 18:34
  • I was mistaken. "The game ends when a player wins" is in fact taken directly from the rulebook. I still find it unclear, even after your edit, that your issue in paragraph two is specifically with the chosen proof method. You appear to take issue with "everything besides those two points". That sort of broad issue is not something I can possibly address.
    – Rainbolt
    Jan 14, 2015 at 18:35
  • @murgtroid99 PERFECT! I needed a great example like that. "Can I do X when I have priority?" Assuming that the answer is "No.", what rule would you quote? Every single rule regarding priority?
    – Rainbolt
    Jan 14, 2015 at 18:40
  • 1
    But that is the point. You could reduce your entire argument to the sentence I put in quotation marks, and it would have exactly the same logical conclusion. Everything else--the made up rule, the proof by contradiction, the other premises, the formal proof--is completely unnecessary and distracts from the actual argument. The fundamental problem is the proof by contradiction, because everything else was introduced to contribute to that proof, but the other stuff is still part of the problem.
    – murgatroid99 Mod
    Jan 14, 2015 at 18:44
  • 2
    You asked a question and I answered. The fact that you don't know I'm right doesn't make me wrong. And I am still not going to argue about hypothetical rules.
    – murgatroid99 Mod
    Jan 14, 2015 at 19:58
  • 1
    You're right, you didn't mention that. I was trying to interpret your claims generously, and apparently I failed. I've removed that clause. And I've decided that I don't actually care about this argument any more. I doubt it will affect site policy, and people will still get good answers to their question, even if you don't give them. I'm just saying this so you don't wait for me to respond to any future comments. I probably won't respond to this thread again.
    – murgatroid99 Mod
    Jan 14, 2015 at 20:46

I know I'm guilty of it. I respond harshly when I didn't logically think of something. It seems like someone is putting me down because I didn't think of it. Doesn't make it right, but it happens. When down-voters don't explain themselves in the comments I don't worry about it too much.

I know when I was still playing MtG, the first thing that anyone said when we had a new player was the caviat "Unless the card says otherwise". I tend to lean toward the second option. I am allowed to do something unless the rules say otherwise.

The answer was not logically flawed. It made perfect sense to me. I think the negativity may have been generated because you didn't back your answer up with quoted rules. Not a requirement for an upvote, but your answer certainly didn't garner downvotes either.

  • Your friends misinterpreted one of the Golden Rules of Magic. The rule allows the card to have priority over the rules when a conflict occurs. It by no means allows you to "do something unless the rules say otherwise". MTG rules are definitely permissive rather than restrictive. There was some debate about whether the rules should state that explicitly.
    – Rainbolt
    Jan 14, 2015 at 17:52
  • Just in general I mean. This is after we go over the rules. And was a long time ago...I started playing in 1997. Jan 14, 2015 at 17:55
  • Unfortunately I disagree a bit. I'm not sure which of the forms of the answer you're talking about, but downvoters did try to explain in the comments (though not to Rainbolt's satisfaction). The answer was at the very least unnecessarily convoluted, which makes it less useful (and downvotes do mean "not useful"), and not actually backing up your answer with rules makes it less useful as well.
    – Cascabel
    Jan 14, 2015 at 21:09
  • @Jefromi Please see the part of this question that states "Note: If a rule did exist which stated that you cannot do something, that would clearly be preferable. I only want to discuss the case where there is no such rule." You can't back up your answer with rules that do not exist. The best you can do is quote the rules that do exist, and then claim that what you are trying to do is not among them.
    – Rainbolt
    Jan 14, 2015 at 21:49
  • @Rainbolt Don't worry, I understood that. But nonetheless, it can be helpful to reference specific rules. By quoting the portion of the rules where the rule in question would appear if it did existed, you help show the reader that it doesn't exist. If someone says "my friend told me that when I buy a development card, I have to put on a hat" you might say "No, you don't, here's what it says about buying a development card. No hats!"
    – Cascabel
    Jan 14, 2015 at 22:16

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