HOH "outdated"

[ShaneP]

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This "complete information" idea is commonly bandied about. It's true in theory, but not in practice, at least among amateur players.



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Jeff, I've seen you make this claim a few times. In game theory terminology, chess is indeed a game of complete information, and poker is a game of incomplete information.

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That's what I said. I also am saying that in practice you don't make all your decisions based strictly on game theory. In many actual game situations in chess, you can knowingly make theoretically incorrect moves and still gain an advantage over a (non master) opponent. You obviously cannot do this in a game theory sense. The fact that chess is theoretically a game of complete information is irrelevant sometimes, yet people keep talking about it as if chess is a game played against perfect computers, not against people. Since their assumption is wrong, sometimes their conclusion is wrong.

In some ways, amateur chess in practice has more in common with poker, a game of incomplete information, than with a game of complete information. This is the point I'm trying to get across.

For example, in poker you might say "I'm not sure what my opponent has and he's not sure what I have, but based on his play I think he has something like ABC, and he probably thinks I have something like XYZ."

In chess you might say "I'm not sure what my opponent's up to here, but based on his last couple moves he's very worried about this threat, even though there is an easy defense to it that he's obviously not aware of. I will continue with this "bluff". I might be exposing myself here, but I'm not sure since I can only imagine a couple moves ahead, and furthermore I doubt he'd see that anway even if it is an exposure."

I'm trying clear up the misconception that just because a game is one of "complete information", you can't bluff and you can't outplay your opponent in many of the same ways you can in poker. If your opponent does not know how to use information or is not aware of it, then that information might as well not exist, making the game one of incomplete information in practice. And then the game plays more like a theoretical game of incomplete information.

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Jeff--

I do (and did) see your point, and I understand it. My only point is that you're messing up the terminology--the game itself is a game of complete information, and so to attach a tag of 'incomplete information' is misleading. What you're saying is that it is a game of complete information, but the equilibrium is very difficult (if not impossible in some situations to find) so that opponents can and do play non-equilibrium strategies. As such, you can play non-equilibrium strategies (your 'bluff') because that's a best response to your opponent's mistakes.

So the game is the game--it doesn't become incomplete information because of what or how some people play. If I were to sit down and play a game of Go, it would still be a game of complete information, even though I would play it terribly, and not even close to an equilibrium strategy. So my opponent might catch on and make 'mistakes' of his own to induce more mistakes from me, or even bluff (I don't know enough about Go to know if that's even possible...).

What I'm saying is that it is true in theory and practice in Go, Chess, Checkers, Tic-Tac-Toe, and whatever else, that the game is of complete information. To claim otherwise is either wrong, or as in your case, abusing the nomenclature. That's all I'm saying, and being a theorist in the field, I don't like seeing people abuse the notation...again, not saying your point is wrong, it's just that your wording is poor.

Shane

[jeffnc]

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What I'm saying is that it is true in theory and practice in Go, Chess, Checkers, Tic-Tac-Toe, and whatever else, that the game is of complete information. To claim otherwise is either wrong, or as in your case, abusing the nomenclature. That's all I'm saying, and being a theorist in the field, I don't like seeing people abuse the notation...again, not saying your point is wrong, it's just that your wording is poor.

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We constantly have to invent new wording to get new ideas across. Let me give you an example. If you were a "theorist in the field" of zoology, you'd know that balsa wood is a hardwood and pine is a softwood. But that's pretty misleading isn't it? So I would tell most people that balsa is a soft wood and you would correct me and say no, it must be a hardwood.

Yes, I know chess is a game of complete information. But in practice that's pretty misleading. In practice it's a game of incomplete information. This is no more wrong in my view than saying that balsa is a hardwood and balsa is a soft wood in practice.

[ShaneP]

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What I'm saying is that it is true in theory and practice in Go, Chess, Checkers, Tic-Tac-Toe, and whatever else, that the game is of complete information. To claim otherwise is either wrong, or as in your case, abusing the nomenclature. That's all I'm saying, and being a theorist in the field, I don't like seeing people abuse the notation...again, not saying your point is wrong, it's just that your wording is poor.

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We constantly have to invent new wording to get new ideas across. Let me give you an example. If you were a "theorist in the field" of zoology, you'd know that balsa wood is a hardwood and pine is a softwood. But that's pretty misleading isn't it? So I would tell most people that balsa is a soft wood and you would correct me and say no, it must be a hardwood.

Yes, I know chess is a game of complete information. But in practice that's pretty misleading. In practice it's a game of incomplete information. This is no more wrong in my view than saying that balsa is a hardwood and balsa is a soft wood in practice.

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Sorry, can't help myself...if I was a 'theorist in the field' of zoology, I wouldn't necessarily know anything about trees. Now, if I were a botanist...(sorry for the nit, but it kind of goes with my point). But it would be pretty easy to explain to someone confused about it that (I think..I'm not a botanist) hardwood versus softwood is an issue of rigidity, not of strength.

But the key thing is the definition of complete information isn't open to interpretation. Are there hidden chess pieces? Do the pieces move in a different way that isn't known to both participants? Complete information games are defined as having the state of the world/system known to all. Complete information versus Incomplete information just has to do with the rules of the game, it has nothing to do with how complex the game is, or if people are playing the Nash Equilibrium strategy.

Looking at it another way...would you say Tic-Tac-Toe is a game of complete information? (it is). But according to your 'definitions', it would become a game of incomplete information if I was playing an idiot. Or I could define a simple game of incomplete information where the participants easily identify and play the Nash Equlibrium, and evidentally this would make it (according to a slight extension of your definition) a game of complete information. This makes your definitions useless, since now you need to specify the complexity of the thinking of the participants.

If you want to use a new word, fine. But when you take an established word with a concrete meaning and use it for something else, you muddle up the interpretation and argument.

I'm guessing a bit of trying to get chess called a game of incomplete information is that you're trying to show poker is a game of skill. That is, chess is a game of skill, and then by calling chess a game of incomplete information, those games then can be games of skill and thus poker is. But what I would say is just because a game is a game of incomplete information, doesn't make it a game without skill. After all, there are games of complete information that are entirely games of chance (Chutes and Ladders for a prime example), so the categorization of Complete or Incomplete information doesn't (or shouldn't) determine whether a game is skill or luck.

[fraac]

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Sorry, can't help myself...if I was a 'theorist in the field' of zoology, I wouldn't necessarily know anything about trees. Now, if I were a botanist...

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My ex-girlfriend, a theorist in the field of zoology, is fond of the fact that balsa is a hardwood and talks of it often. Also, apparently, whelks have the largest penis-to-body ratio of any animal. Point is, when you can see the other guy knows what he's talking about, as jeff does, then mere pedantry loses arguments.

[ShaneP]

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Sorry, can't help myself...if I was a 'theorist in the field' of zoology, I wouldn't necessarily know anything about trees. Now, if I were a botanist...

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My ex-girlfriend, a theorist in the field of zoology, is fond of the fact that balsa is a hardwood and talks of it often. Also, apparently, whelks have the largest penis-to-body ratio of any animal. Point is, when you can see the other guy knows what he's talking about, as jeff does, then mere pedantry loses arguments.

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Yeah, that's fine...if you want to ignore the body of the argument and focus on what was more or less a joke, ok. But that wasn't the point at all. I could care less about hardwood versus softwood...I probably shouldn't have even said that, because (I know that was being a bit nittish) people would latch onto that rather than the actual argument...oh well, I was just trying to bring a slight amount of humor

[fraac]

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Sorry, can't help myself...if I was a 'theorist in the field' of zoology, I wouldn't necessarily know anything about trees. Now, if I were a botanist...

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My ex-girlfriend, a theorist in the field of zoology, is fond of the fact that balsa is a hardwood and talks of it often. Also, apparently, whelks have the largest penis-to-body ratio of any animal. Point is, when you can see the other guy knows what he's talking about, as jeff does, then mere pedantry loses arguments.

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Yeah, that's fine...if you want to ignore the body of the argument and focus on what was more or less a joke, ok. But that wasn't the point at all. I could care less about hardwood versus softwood...I probably shouldn't have even said that, because (I know that was being a bit nittish) people would latch onto that rather than the actual argument...oh well, I was just trying to bring a slight amount of humor

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The 'body' of your argument is that you like terms to be used precisely and to not shift in meaning (as all good language does) when no one here was confused anyway. You are arguing to an empty room. Jeff's point that the amount of information in chess increases with ability, and thus the best strategy not only changes but relies on a completely different underlying theory, has interesting implications. If you can find the link to curtains' turn in The Well, he hints at exploitative chess strategies being a new avenue for him. And he's a pro. So, it's interesting. No one was talking about whether poker is a game of skill, but if you must be precise then I suggest that exploitation takes more 'skill' than does the application of a theoretically 'optimal' strategy, and poker is more skillful than high-level chess. Which is, like your argument, pointless semantic marshland.

[ShaneP]

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Sorry, can't help myself...if I was a 'theorist in the field' of zoology, I wouldn't necessarily know anything about trees. Now, if I were a botanist...

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My ex-girlfriend, a theorist in the field of zoology, is fond of the fact that balsa is a hardwood and talks of it often. Also, apparently, whelks have the largest penis-to-body ratio of any animal. Point is, when you can see the other guy knows what he's talking about, as jeff does, then mere pedantry loses arguments.

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Yeah, that's fine...if you want to ignore the body of the argument and focus on what was more or less a joke, ok. But that wasn't the point at all. I could care less about hardwood versus softwood...I probably shouldn't have even said that, because (I know that was being a bit nittish) people would latch onto that rather than the actual argument...oh well, I was just trying to bring a slight amount of humor

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The 'body' of your argument is that you like terms to be used precisely and to not shift in meaning (as all good language does) when no one here was confused anyway. You are arguing to an empty room. Jeff's point that the amount of information in chess increases with ability, and thus the best strategy not only changes but relies on a completely different underlying theory, has interesting implications. If you can find the link to curtains' turn in The Well, he hints at exploitative chess strategies being a new avenue for him. And he's a pro. So, it's interesting. No one was talking about whether poker is a game of skill, but if you must be precise then I suggest that exploitation takes more 'skill' than does the application of a theoretically 'optimal' strategy, and poker is more skillful than high-level chess. Which is, like your argument, pointless semantic marshland.

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Not quite an empty room; there have been replies. And I would say it's interesting a game of perfect information can have room for 'non-optimal' strategies being better than the optimal replies based on one's opponent.

But the argument jeff put forward, if your summary is correct, is wrong. There's more information if I'm good at chess? hardly. I can see the board, I can see the pieces, I know how they move. All the information is readily available to any participant. Pieces are not revealed to a GM when they remain hidden from someone of my chess ability. I think the only 'pointless marshland' is the place where people define words however they want, and use them to prove whatever it is they want.

Although, my guess is there's a mixing of information (the state) with the action space for a game. What my opponent is doing or thinking in no way influences the information in a game as far as calling it complete or incomplete. It is a part of the game, and it would influence my strategies, but calling it something it isn't defeats the purpose of defining what it is in the first place. A good language may have words shift meaning, but good science has concrete definitions that are not subject to the whims of the person uttering the words. And the phrase 'incomplete information' is and was being used in a scientific sense, quite incorrectly--and I've seen jeffnc use it in that way several times in previous threads...

[jeffnc]

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Sorry, can't help myself...if I was a 'theorist in the field' of zoology, I wouldn't necessarily know anything about trees. Now, if I were a botanist...(sorry for the nit, but it kind of goes with my point).

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Oops, meant botany.

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But it would be pretty easy to explain to someone confused about it that (I think..I'm not a botanist) hardwood versus softwood is an issue of rigidity, not of strength.

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I don't agree. In any way an average person could measure, balsa, a hardwood, is softer, weaker and less rigid than pine, a softwood.

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But the key thing is the definition of complete information isn't open to interpretation.

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That's because you're a theorist.

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Are there hidden chess pieces?

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In various ways, yes indeed. Very often you hear a player say "I didn't even see the bishop!" So literally the piece was not seen. And then there are more subtle forms of it.
http://www.101chesstips.com/hidden-attacks.jsp

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Do the pieces move in a different way that isn't known to both participants?

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This often occurs with newer players. They do not know they can't castle through check, or can't remember how to castle queen side, believe that a pawn must always be queened when it makes it to the ultimate rank, and sometimes don't even get en passant pawn captures wrong.

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This makes your definitions useless, since now you need to specify the complexity of the thinking of the participants.

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This makes about as much sense as saying you don't need to account for your opponent's knowledge of the game when playing poker.

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If you want to use a new word, fine. But when you take an established word with a concrete meaning and use it for something else, you muddle up the interpretation and argument.

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Someone as educated as yourself really shouldn't have any problem allowing words to mean different things in different contexts. Hard woood, for example.

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I'm guessing a bit of trying to get chess called a game of incomplete information is that you're trying to show poker is a game of skill. That is, chess is a game of skill, and then by calling chess a game of incomplete information, those games then can be games of skill and thus poker is.

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That really has nothing to do with it. You're too intent on definitions of words. It doesn't matter that chess is a game of complete information if it doesn't play that way in real life. This would be like saying Newtonian physics breakdown when I get into my space ship and start flying near the speed of light. Well, what I'm trying to say is that we're all just sitting here on Earth, so it's a moot point. You are going to do a whole lot better sticking with Newtonian physics to get all your work done because it works, even though physicists know that it doesn't work in general (it does not describe the universe accurately). I'm not trying to say that Einstein's physics are wrong (or that quantum physics is wrong). I'm trying to put some perspective on the problem by saying that if you're a mechanical engineer here on Earth, you still need Newtonian physics to do your job. It doesn't matter that it isn't a unified theory of physics.

[ShaneP]

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Sorry, can't help myself...if I was a 'theorist in the field' of zoology, I wouldn't necessarily know anything about trees. Now, if I were a botanist...(sorry for the nit, but it kind of goes with my point).

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Oops, meant botany.

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But it would be pretty easy to explain to someone confused about it that (I think..I'm not a botanist) hardwood versus softwood is an issue of rigidity, not of strength.

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I don't agree. In any way an average person could measure, balsa, a hardwood, is softer, weaker and less rigid than pine, a softwood.

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But the key thing is the definition of complete information isn't open to interpretation.

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That's because you're a theorist.

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Are there hidden chess pieces?

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In various ways, yes indeed. Very often you hear a player say "I didn't even see the bishop!" So literally the piece was not seen. And then there are more subtle forms of it.
http://www.101chesstips.com/hidden-attacks.jsp

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Do the pieces move in a different way that isn't known to both participants?

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This often occurs with newer players. They do not know they can't castle through check, or can't remember how to castle queen side, believe that a pawn must always be queened when it makes it to the ultimate rank, and sometimes don't even get en passant pawn captures wrong.

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This makes your definitions useless, since now you need to specify the complexity of the thinking of the participants.

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This makes about as much sense as saying you don't need to account for your opponent's knowledge of the game when playing poker.

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If you want to use a new word, fine. But when you take an established word with a concrete meaning and use it for something else, you muddle up the interpretation and argument.

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Someone as educated as yourself really shouldn't have any problem allowing words to mean different things in different contexts. Hard woood, for example.

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I'm guessing a bit of trying to get chess called a game of incomplete information is that you're trying to show poker is a game of skill. That is, chess is a game of skill, and then by calling chess a game of incomplete information, those games then can be games of skill and thus poker is.

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That really has nothing to do with it. You're too intent on definitions of words. It doesn't matter that chess is a game of complete information if it doesn't play that way in real life. This would be like saying Newtonian physics breakdown when I get into my space ship and start flying near the speed of light. Well, what I'm trying to say is that we're all just sitting here on Earth, so it's a moot point. You are going to do a whole lot better sticking with Newtonian physics to get all your work done because it works, even though physicists know that it doesn't work in general (it does not describe the universe accurately). I'm not trying to say that Einstein's physics are wrong (or that quantum physics is wrong). I'm trying to put some perspective on the problem by saying that if you're a mechanical engineer here on Earth, you still need Newtonian physics to do your job. It doesn't matter that it isn't a unified theory of physics.

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As I said, sorry about the zoology-> botany quip, just trying to be slightly humorous. I know it wasn't too good.

The 'hidden piece' isn't information that's not there. That's not the game--that's the players who play the game. The game has in it's rules that all the pieces are visible. And 'hidden check' isn't because there was something that wasn't observable previously suddenly materialized.

But, what I've said before, the game is the game. If people aren't playing optimally, you can't play the NE strategy and expect it to be the best. So yes, you'd have to adjust your chess, your poker, whatever, to exploit fully your opponent's mistakes. But a game is defined by it's rules and payoffs, and nothing is hidden from players. Yes, it's complex, so noone knows the NE, but that doesn't change the game.

And I think the better analogy is a mechanical engineer using Aristotlean (I'm sure I spelled that wrong) physics--there are changes to equilibrium concepts for exactly the problem you're describing, where people don't always play the NE strategies. If you're interested, check out 'trembling hand equilibrium' or 'cursed equilibrium'. Those can keep the information in the game constant while at the same time accounting for people's non-equilibrium actions.

[Eponymous]

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But it would be pretty easy to explain to someone confused about it that (I think..I'm not a botanist) hardwood versus softwood is an issue of rigidity, not of strength.

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I don't agree. In any way an average person could measure, balsa, a hardwood, is softer, weaker and less rigid than pine, a softwood.

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A note on the side conversation that has developed here:

It seems even experts in the field would say that balsa is softer than most softwoods (and just about every hardwood). What makes it a hardwood is the type of tree it comes from, not its mechanical properties. It is known to be a very soft member of the hardwood family, at least according to Wikipedia.

From an engineer's perspective (I have a mechanical engineering background), hardness is a different property than strength and rigidity (typically referred to as elastic modulus or stiffness). The three are different and are measured differently. Anyone who has made a dent in a piece of balsa with just their fingernail (most closely aligned with a hardness test) knows that it is soft. This doesn't tell you much about it's tensile or compressive strength or its stiffness.