What is the purpose of chess engines?

[Henk]

I don't like lczero participating in monthly blitz tournament. Some endgames took far too many moves and they were played with an increment.
Only thing what lczero was doing was avoiding draws by fifty moves rule. So we had to wait until there were no pawns left over.

[Michel]

For me truth in chess is the game theoretic value of a position. Sadly chess engines cannot give this rigorously. Not even in a probabilistic sense.

[jp]

People that are looking for "chess truth" assume "infinite time" for both sides, but then the chess truth is that in those conditions it's best to never make a move!

There is no assumption of "infinite time". I don't know why you keep repeating this claim over and over again.

If you are not interested in chess truth, that's fine, but it's got nothing to do with infinite time. The best players have always been interested in chess truth and their time control is much shorter than you with your engines playing correspondence chess.

[Kappatoo]

A note concerning 5:
Grandmasters rely heavily on chess engines. Often, they do leave the engine run for a night on a specific position--to make sure they aren't missing something. And often, they just go through some opening line with an engine running, looking for possible novelties. Nowadays, much of opening preparation is about finding something early on that your opponent might not have considered and then analyzing this line in depth. The reason is that most main lines--lines known to both players--have been analyzed to draws.
There are many reasons why one would want to analyze with more than one engine. In each case, this is only really useful if the engines give sufficiently different verdicts. Another engine might just help you find another candidate move, or suggest that the position isn't as uninteresting as it seemed.
In a recent interview with Jan Gustafsson, Nakamura talked about how analyzing with Leela helped him see new perspectives on lines he had previously analyzed with Stockfish. One thing that many strong players seem to agree on is that what's good about Leela is that it doesn't always give you these '0.00' evaluations that suggest that everything is a dead draw. It might be that Leela is thus better at detecting practical chances--which is, of course, very important for grandmasters.

[Dann Corbit]

There are at least two ways we can look at it. We can use the definition of Kierkegaard, "Truth is man's approximation of thought to reality."
So, in some sense, it means "Our best approximation."

or we can think of it like science. At one time we thought that planets and stars were shiny things stuck on the surface of concentric Crystal spheres. It was a model that worked O.K. for a while. Then Copernicus showed our model was not quite right. Then Newton showed how the planets moved, due to gravity. Turns out he was not quite right either, as Einstein showed deformation of space time even explained strange things like the bending of light and the passage of Mercury. Who is to say we will not have future refinements?

In a similar way, we have new and better instruments and techniques to examine a chessboard. Our Best approximation gets closer to reality all the time.

I do have one objection to Kierkegaard, though. I think that the truth is the underlying reality ( one of the times that Plato was right )

[Ovyron]

People that are looking for "chess truth" assume "infinite time" for both sides, but then the chess truth is that in those conditions it's best to never make a move!

There is no assumption of "infinite time". I don't know why you keep repeating this claim over and over again.

Because if it didn't assume "infinite time" then it'd assume a certain time that the game has left, or a certain time that the next moves from the game will be played. If it's not "infinite time", then, what is it? Because in all these discussions games are never played to completion, and if they're played, we get plenty, but each at a laughable time control, and none of that has to do with the truth (which requires a chess clock - or at least, an implied one.)

I throw back at you the question of what is this truth?

What is wanted is that for any given chess position, you get moves ranked from best to worst, so that in any given position, if you played the 1st ranked move, you'd get the best performance against any opponent, under any condition, so deviating from the truth wouldn't make sense in any case.

Not only that, but the moves would have a number to their side, the higher the number, the better white performance, the lower the number, the better black performance, and a draw (50% performance) would be 0.

These numbers would apply to any chess position, so if a line was 50 and another was 49, in all cases playing from the 50 position would be better for black.

Note ChessDBCN is a representation of what I'm talking about, though it doesn't implement asymmetric eval, and it's of course a work in progress in where you can bend the truth at will by showing it better variations than what it currently knows (for instance, it has Bxc6 instead of Re1 as the mainline of the Spanish, one could go to either move and decrease Bxc6's score or increase Re1 and change their ranks), but that's how chess truth would look like (except it would never change because evals are final.)

In practice, however, once a game is being played, you eventually reach new territory, a position never seen before by anybody and you have nothing about it, you have to come up with your best performing move on the fly, and knowing this, the positions leading to this had to be played so that your time left to play the game allows you to play it correctly. It is useless if this new never seen position is one where you can mate your opponent with certain moves (that exist), if you have not enough time to find those moves and the position is so complex it's more likely that you'll blunder and lose.

Most people dedicate their time to using chess engines to analyze postmortem games (after they're over), studies (of a famous position) or chess puzzles (compositions from someone's mind), but if they don't find there's a winning move they claim "this position is a draw with best play" as the truth and move on, even though in a real game nobody knows what would happen.

Some people have claimed that they can always rank a non-losing move at the top, and basically solve chess on the fly and become unbeatable, but I don't think chess truth ends there, you rank at the top the moves that make it the most likely for the opponent to blunder, and it's tricky because those moves tend to be unclear and be dangerous to play for yourself.

My conclusion is that chess analysis doesn't make any sense, it only makes sense to play games, analysis is done to rank the moves in real time with your time available and play the move against someone, and if your performance is good, your ranking is good. You can't know if your ranking is good if you only analyze.

[S.Taylor]

42531
In that order.

[jp]

People that are looking for "chess truth" assume "infinite time" for both sides, but then the chess truth is that in those conditions it's best to never make a move!

There is no assumption of "infinite time". I don't know why you keep repeating this claim over and over again.

Because if it didn't assume "infinite time" then it'd assume a certain time that the game has left, or a certain time that the next moves from the game will be played. If it's not "infinite time", then, what is it? Because in all these discussions games are never played to completion, and if they're played, we get plenty, but each at a laughable time control, and none of that has to do with the truth (which requires a chess clock - or at least, an implied one.)

We are just interested in the truth of the position in (more than) a tablebase sense. ("More than" because tablebases don't give all the information we might be interested in.) You don't seem at all interested in that, but it's not about time.

[Uri Blass]

What is wanted is that for any given chess position, you get moves ranked from best to worst, so that in any given position, if you played the 1st ranked move, you'd get the best performance against any opponent, under any condition, so deviating from the truth wouldn't make sense in any case.

Not only that, but the moves would have a number to their side, the higher the number, the better white performance, the lower the number, the better black performance, and a draw (50% performance) would be 0.

These numbers would apply to any chess position, so if a line was 50 and another was 49, in all cases playing from the 50 position would be better for black.

This is impossible.
You cannot get the best performance against any opponent with the same moves.

There may be a drawn position when forcing a draw is the best move against opponent A but against opponent B it is better to play a losing move because B is not going to find the way to win and make a mistake and lose.

[Ovyron]

We are just interested in the truth of the position in (more than) a tablebase sense. ("More than" because tablebases don't give all the information we might be interested in.) You don't seem at all interested in that, but it's not about time.

But your definition of "truth" is vague.

Does your truth include chess clocks? If it doesn't then there's no difference between no chess clocks and infinite time, that's what I'm saying.

There may be a drawn position when forcing a draw is the best move against opponent A but against opponent B it is better to play a losing move because B is not going to find the way to win and make a mistake and lose.

But you can't know that in advance. What you're describing is not chess, but "hope chess", where you swindle in the hopes that your opponent will miss something. Any definition of chess truth would avoid playing losing moves, because you don't know if your opponent is able to find their refutation.