Sally Simpson: Hi,
Yeah I meant players strengths, we have enough armchair psychiatrists to sort out that view of the players.
Ignoring computers for now as they need a giant leap in a new direction to play like humans, the views of strong players should be noted by the fact they are strong players and therefore in theory should understand the game better.
(Of course although they understand the game better this will not stop Kibitizers from advising them on what openings to play, how they should train, what seconds to use and what side to part their hair. I think Carlsen should sport a Mohican for 2016 just to show he means business.)
However these strong players do change their minds on who was the greatest.
Aronian was of the opinion it's Alekhine in 2012, then in 2015 it was Kasparov.
In 2005 Kramnik had Kasparov as the best ever till 2011 when he changed it to Anand.
Anand in 2008 said Fischer and Kasparov with Kasparov slightly ahead. In 2012 he changed his mind to simply just Fischer.
Carlsen recently rated Fischer & Kasparov as the best but also gave a firm nod in Kramnik's direction. Possibly when Kramnik retires he will be Carlsen's top choice.
in 2001 Chess Informant ran a readers poll it came out. Fischer, Kasparov, Alekhine, Capablanca, Botvinnik, Karpov, Tal, Lasker, Anand and Korchnoi.
I reckon if they took a poll of all the players over 2700 and keeping the choice to inactive players then Kasparov would figure in everyone's top three and in the majority of cases have him as number one. (provided of course they can stick to chess and not chess politics.)
Grades are OK in lieu of a better method (it's probably the best we will ever have) but inflation and regional games where an overrated player can spread his grade around like the pox making it possible to get a grade of over 2600 without ever beating a player over 2600 thus giving birth to the ridiculous term 'a weak grandmaster', can produce lopsided and some eyebrow raising results.
If you think that Nakamura, Wes So, Radjabov, Karjakin, Morozevich and Ivanchuk are better than Fischer and Karpov (all of those six have posted higher grades than Fischer and Karpov) then the grading system is your back up.
Although all six are admirable players capable of displaying flashes of pure brilliance ...better than Fischer and Karpov? (you might get more than a few disagreeing with you on that one.)
I'm also thinking if you asked any of that six if they thought they were better than Karpov and Fischer they would all answer 'No' or hedge their bets and say 'Not yet'.