That is a long winded answer, that doesnt explain why "positional" chess isnt an inherent part of the game. Positional chess is as much a part of chess as tactical play is. And this is where chess engines destroy human opponents.
Humans v Houdini chess engine (Elo 3300)

The irony of this discussion is each position only has one game theoretic
value (W,L, or D) but has a myriad of values due to the limitations of search
and the strengths and styles of the participants.

Engines still have evaluation functions though, which includes positional elements. When they plonk a Knight on e5, they don't have calculated up to a material gain just yet, but their evaluation function takes into account that a centralized Knight is worth slightly more than a Knight on a rim for example (all other things being more or less equal at the end of the tree).
But of course, the calculation power is what makes the difference.

Interesting comment pfren... My common sense tells me that a computer rated at 3300 would beat 2800 rated humans every time.
Or at least 24 times out of 25 (according to the ELO rating vs win-probability table).

The irony of this discussion is each position only has one game theoretic
value (W,L, or D) but has a myriad of values due to the limitations of search
and the strengths and styles of the participants.
Nice summary of the essence of chess.

Interesting comment pfren... My common sense tells me that a computer rated at 3300 would beat 2800 rated humans every time.
Or at least 24 times out of 25 (according to the ELO rating vs win-probability table).
I'm standing by my claim that Engine ELO's can't be effectively compared to human ones. That conclusion comes from only my common sense so I'm trying to find more proffesional opinions.

I am pretty certain someone's discovered that Houdini has issues with pawn structures by observing it play. So there's your weakness to target.

Computers have been able to calculate a lot more moves than humans for a long time. The deep thought machine Kasparov beat in 1989 could calculate better than Kasparov but lost soundly because it lacked good evaluation functions. It was good in sharp tactics but lacked an understanding of the position.
The reason they are now able to beat GM is that now they have evaluation functions that allow them to "understand" chess more like humans do, plus they can calculate a lot of variations and at the same time they trim more unuseful variations than 15 years ago, so they can concentrate on the best lines. But the most important thing is the evaluation of the position, even for Houdini, and the parameters of evaluations are decided by humans according to existing theory.
Talking about humans beating machines here it is Nakamura beating Rybka in a blitza game in 2008 http://www.chessgames.com/perl/chessgame?gid=1497429 .

Interesting comment pfren... My common sense tells me that a computer rated at 3300 would beat 2800 rated humans every time.
Or at least 24 times out of 25 (according to the ELO rating vs win-probability table).
I'm standing by my claim that Engine ELO's can't be effectively compared to human ones. That conclusion comes from only my common sense so I'm trying to find more proffesional opinions.
I wouldn't want to be dogmatic about it, and you could well be right. I just assumed that the normal ELO difference relationship would hold irrespective of whether the players were humans or machines.
Talking about humans beating machines here it is Nakamura beating Rybka in a blitza game in 2008 http://www.chessgames.com/perl/chessgame?gid=1497429 .
I thought that Gusev v Averbakh in the earlier posts was an exceptional game but that is pretty ordinary in comparison with this. It's not often that a 3-minute game lasts 271 moves and has the ending BBBBBK v K.
I kid you not.

When a GM actually beats a chess engine, it's usually because of some "stupid" programming glich (that quickly gets fixed later). Not very satisfying, or edifying.
So what did that 4 year old game (cited above) actually demonstrate? Except perhaps that Nakamura was "deathly afraid" of opening up the position, and Rybka foolishly gave up a draw in a "stupid" attempt to win.
Rybka had an easy draw in a closed position, and was up two rooks versus two minor pieces. But it somehow didn't know to just sit and wait, or claim a draw by repetition.
Was this some "Great Lesson Learned" between Man and Machine? Hardly.
It was a fairly mindless game along the e-file, with endless repetition, and a fairly clear draw, until Rybka decided to give back material.
The irony is that so many of these Chess.com threads are chockablock with "experts and coaches" endlessly intoning that we should all play "mainline (big theory) openings" like the Ruy Lopez or Sicilian to improve our overall play.
But when it comes to GM's playing against engines, all that grand advice is quickly abandoned, because (as we all know), it's "death by a thousand cuts" when playing against the newer engines.
Does it really matter what time control we are talking about? Probably not. The 3300 rated engine will win, regardless.
Humans used to run foot races against early automobiles, when the result was still in question. Those days are long gone, indeed.
Ditto with the newer chess engines of today. Get over it.

That game demonstrates an enormous engine weakness. Rybka is up material, so it thinks it's winning. Take away the fifty move rule and it would still think it's winning 1000 moves later. With the fifty move rule in place, the program felt compelled to push it's material advantage and made blunders, just to avoid the draw.

By the way, it's true: computer ratings are not the equivalent of human ratings. Because, as said, computers only play computers. So I wouldn't be sure that some computers actually have a full 500 elo over a world champion. Nevertheless, players of any level will have a really hard time with them -- modern computers are nearly impossible to beat for humans.

It's just the horizon effect...
That game doesn't demonstrate nothing but nonetheless it's pretty impressive. It's not like the human wins playing an odd opening, he wins by going in a certain position in wich he knows the engin will blunder.
BTW I never heard a master saying to play only big theory openings, they always say to play openings you know well (not too much theory but not dubious never used openings) expecially if you are playing with better competition.

Just confirming what some people have said, computer elo is not equivalent to human elo anymore than your chess.com elo is equivalent to a fide rating.
There isn't "computer elo" and "human elo". Computers are just at the high end of the Elo ratings because they're so strong. Their ratings are probably a bit skewed because they only play other computers though. It is almost a new rating system sitting on top of the "human Elo", but it's still the same system.

There isn't "computer elo" and "human elo". Computers are just at the high end of the Elo ratings because they're so strong. Their ratings are probably a bit skewed because they only play other computers though. It is almost a new rating system sitting on top of the "human Elo", but it's still the same system.
Elementary knowledge of statistics and the mathematical model of the ELO system would surely prevent someone claiming such nonsense.

There isn't "computer elo" and "human elo". Computers are just at the high end of the Elo ratings because they're so strong. Their ratings are probably a bit skewed because they only play other computers though. It is almost a new rating system sitting on top of the "human Elo", but it's still the same system.
Elementary knowledge of statistics and the mathematical model of the ELO system would surely prevent someone claiming such nonsense.
I guess so. What's wrong with it?
Demands for evidence cuts both ways. I dont think we have a recorded result of a CC 3 day move game between a super GM and Houdini, which is what leaves open the door for kibitzing.
There is no doubt that humans become stronger relative to machines at longer time controls. The question is, is it enough?
Every day that this challenge doesn't happen, means that it is less likely to occur, at all. Next week brings what? Houdini 3? Rybka 5? each program stronger than the last....
.... and yet, the GM's don't come forward to take up the guantlet, while they still have a glimmer of a chance. One can only ponder the reasons why.
Top GMs do not have much motivation to devote large amounts of time and resources to preparing for a match against a computer. This would probably involve significant work developing strategies to beat a specific engine, I would imagine that it is still possible to do this but the fact is no one really cares anymore, you don't hear about mathematicians trying to prove that they can crunch numbers better than a calculator.
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As far as the question of human understanding goes, people overlook a basic principle, whilst I am not much of a chess player I can see the philosophical issue here. Positional principles are a set of abstractions imposed on the basic logical framework of chess to enhance human ability, they are not inherent in the game as such but they allow humans to make calculations which would otherwise be impossible. A human doesn't 'understand' chess any more than a computer does, they just have a different way of calculating. The machine's method, while much less efficient, is more exact, hence why machine's surpass man's ability quite easily once their efficiency is improved and their calculating ability increased. They still have their weaknesses, but soon these will be too small to exploit and right now there is not much motivation for top players to try.
I'm confused about what you are trying to say? I have highlighted it in red.
How is "positional" chess not an inherent part of the game? Advanced pawns on one side of the board is an inherent part of the game (more space) Just as controlling squares is an inherent part of the game. If i am misunderstanding what you are saying my apologies, but please explain.