TalkChess.com

[Larry Kaufman]

In my view the rating system gradually starts to break down when players are paired with rating differences greater than the value of the first move, say 50 elo or so. Theoretically Black should play for a draw and White should play to win, but once White becomes an underdog he can play for a draw instead. Then results depend on whether Black can avoid this by playing unsoundly but not too much so and on how good White is at playing to draw instead of trying to play properly. So when we talk about the rating of "God" it all depends on whether pairings are limited to close ones or not. The results of experiments will also depend on this. The 4500 estimate does seem reasonable to me if only close pairings are allowed, but not otherwise, unless of course we assume God is reading the minds of his opponents to see what they will miss, a sort of cheating. To put it simply, I think Carlsen could get many draws with White against "perfect" play, but not against a player who modified his play drastically based on how "weak" his opponent was. Ratings cease to measure objective strength of play when this becomes a factor. I see it all the time in actual human play. For example, there is one master against whom I have an overwhelming score (something like 12 wins, 4 draws, no losses), way better than the rating gap of about 150 would predict. The reason is that he plays super-sharp but dubious defenses as Black (mainly the Benoni) which avoid draws against lower-rated opponents and allow him to obtain a much higher rating than he would get against equals or superiors.