Chess will never be solved, here's why

That's a useful rule of thumb for practical play in opening positions. It's obviously not a rigorous game theoretic value.

S'cuse me. I didn't start my argument with any assumption about the theoretical result.

1. We do know how long a chess game can last with legal play under some sets of rules. 

Under FIDE basic rules since 2017 or FIDE rules prior to 2017 there is no finite limit, ℵ₀ can be taken as the minimal (unachievable) limit. Under FIDE competition rules since 2017 it's exactly 8849 White moves.

2. We have no way at the moment of knowing if chess is a win, loss, or draw with perfect play. Indeed you'ld need to alter the FIDE laws for the question to even make sense.

That doesn't mean there is no way of ever knowing (but the answer may be different depending on which set of rules is settled on).

The question doesn't arise in my post, because I'm not talking about perfect play, only legal play.

If you can tell what the error rates are you must have solved chess.

Congratulations - beat @tygxc by five years + the time he's going to take to con someone out of $3M (which could be about the same as a genuine solution might take).

If you want an idea of how SF15 compares with Rybka/Nalimov - which is not just perfect, but also perfectly accurate from the position below - you could always ask Coach, because SF15 is what he uses to decide.

Not sure how you're scoring, but I assume it's based on SF15.

IF using SF15 gives perfectly accurate play (as in Black Rybka/Nalimov in the example I posted) a CAPS2 score of 66.9 that might suggest the best play we have today from the best chess engine we have today is actually not very good (while recognising that anything else that plays without tablebases is considerably worse).

And to compare Carlsen to SF, you should ask both Carlsen and SF if you want an unbiased result. If you just ask SF, it's likely to agree with itself whether it's right or not.

See?  Much better.  You should follow my advice more often.  If people didn't know it was you, this would sound relatively normal.

Chess engines don't uniformly improve necessarily.

I practice KNN v KP quite a lot against engines.

I had a version of Rybka specially strengthened for endgame play about 20 years ago that could reliably do White mates in 50 (though not usually in 50 moves). No version of SF can; the limit is about 36. Also SF12 is considerably weaker at that endgame than SF11 and weaker than SF8. 

ICCF players are like lab assistants.  They run around between engines gathering results and pick the best one.  Occasionally they remind the engines to check a line the engines had been ignoring..."you missed this test tube over here".

I don't understand that conclusion.

Can you give some more detail. What, exactly, do you mean by, "played/analyzed in retrograde"?

In the interest of actually helping you, I will point out that light hearted withdrawal does work, but if you post 3 times in succession, it belies the nonchalance you are attempting to project.  I have some UK coinage left over, I'll swap with you the next time I am going from London to Fort William.

When computers beat consistently  the best human players, chess is solved, more difficult for the GO game though...

No problem. Just describe in detail the steps that were performed to produce your figures for SF and MC, so we can understand what they represent.

Just saying, "retrograde analysis", isn't enough for that. It could lead to a Nalimov tablebase, a Syzygy tablebase or one of Marc B.'s DTC tablebases or the figures you included in your post. I'm interested in what the last are. 

Just as when cars manage to go faster than the best human runners we can say we've cracked warp drive.

These are the definitions of "solved" being discussed:

https://en.wikipedia.org/wiki/Solved_game

Wow nice

No they're not really.

None of them mention any time period.

A strong solution of a soluble version of chess can be produced in less time than it takes to  produce a set of rules for the soluble version. Such solutions have been known since chess was invented.

The Wikipaedia definitions call only for an effective procedure and say nothing about practicality or tractability.

What is being discussed, irrespective of the definitions being quoted by people discussing it, are the definitions I gave here and here. (Excepting @tygxc who is discussing big red telephones and @Optimissed who is discussing his mother in law, the meaning of life and his unfeasibly large brain.)

I'll repeat them.

A (timely) weak solution means that for the initial position either a proven (timely) strategy has been determined for one player that achieves a win for that player against any opposition, or a proven (timely) strategy has been determined for each player that avoids a loss for that player against any opposition. 

A (timely) strong solution means that for all legal positions either a proven (timely) strategy has been determined for one player that achieves a win for that player against any opposition, or a proven (timely) strategy has been determined for each player that avoids a loss for that player against any opposition. 

In this discussion time is of the essence, so, for example, the Checkers solution which reportedly needs about two minutes to produce a move, is not a solution of 1 minute bullet Checkers and the strong solution of chess I said eatlier could be simply written out would not be a solution of any form of chess that could actually be played, because in all probability nothing that was capable of playing chess could persist long enough or find enough working space to carry out the strategy.

Sorry. Clear as mud to me.

You apparently decide first of all where MC or SF went wrong in a series of games. How? 

You then decide on an optimal path that should have been played. How?

You then run a series of games in SF starting at the end of your new path and working your way back one move at a time through the path for the next game in the series, after which you say SF will correct SF's or MC's mistake.

Does that always work and why?

Does SF then follow your amended path at all points and why?

You say you then have a scoring difference. 

What is it?

You show:

Stockfish dev-20221221:   7/4/10/14/1/4/2/2/41/6/3/12/1/17/2/4/3/4/17/5/0/11/1/1/3/26/6/2/2/10/14/2/4/28/9/3/2/3/5/8/2/4/6/5/9/8/4/7/2/0  => Average=0.07

Carlsen Magnus:   2/10/10/21/14/23/23/4/30/22/49/8/4/15/18/35/6/8/16/5/11/4/9/13/14/7/5/12/7/20/12/27/7/14/1/13/8/2/18/7/11/10/10/6/4/10/2/4/13/7  => Average=0.12

but the averages after the double arrow are obviously not averages of the preceding numbers between the slashes. What are the numbers, how do they relate to the average and what is the average an average of? 

Everything is gobbledygook to you @Optimissed because you can't be bothered to understand any of the terms or concepts that people use in discussions of this subject and make up your own cack handed versions instead.

I don't take much notice.

@DeperateKingWalk

How does my description differ from what you described?

Are my questions on the process unreasonable? You have only partially answered the one about what your averages are and ignored the rest.

I didn't assume anything at all about the number of moves in the games. Why do you say that?

I understand retrograde analysis well enough. I'm asking you how you are applying it to arrive at the figures you quoted and most of all what the figures are.

I'll try again. What are the numbers between the slashes and what are the averages averages of? Since you say its an average over the positions in the games you have presumably assigned some number (a score) to each position, but you have nowhere said how that number is determined. All I'm asking you for is an explanation of what your figures are. Is that difficult? 

Well, in that case, your definition is also incomplete.  Solving implies being solved for human beings in a perceivable manner, ergo the universe must currently be in a state that allows for perception and understanding by the bulk of humanity, solutions achieved inside black holes must be covered under different criteria, etc.

Seriously, though, the definitions do not cover practical considerations any more than the definition of a hammer explains how to forge metal.  The definition describes the outcome, not the process.  The Wikipedia definitions are adequate to this task, especially for this type of discussion.