It is not even disputable: Karpov would DEFINITELY WIN in 1975

Karpov would most likely not have won in 1975.  Nor later on.

Heck, it took Karpov 20+ years to get a higher rating than Fischer (and Fischer's rating would still have him in the top 5 today, 50 years later), and it lasted for such a short time that Karpov's camp could not even get 2700chess to post it for years until he could prove that he went over 2790 for less than the span of a single tournament.  When Fischer played the '72 match with a 2785 rating, he had a 120 point gap that is still unequaled (not even close), Karpov wasn't even the #1 rated player when he did it.  Anyone that understands how Elo ratings work knows that Fischer's strength relative to his peers of the time was light years beyond Karpov's.

If he could beat all the Russians' adjournment prep OTB (i.e. without prep) by himself (his team was not near the same strength), then it's not hard to believe he could wipe the floor with Karpov, extensive prep or not. 

It behooves people to remember that there was no engine prep then, so there was no way for Karpov to really prep for facing Fischer the way super GMs do today.  Karpov's team would have been in the same situation as Spassky's team...trying to emulate and predict a level of play *they had no way of reaching*.

You'll be speculating all your life, but Karpov is never going to beat Fischer.  Might as well accept it.  As for asserting that Spassky could have beaten Fischer in '72...

I would listen to both Spassky and Karpov, who considered Fischer the stronger player...and not because they were being humble.

"Karpov would most likely not have won in 1975.  Nor later on.

Heck, it took Karpov 20+ years to get a higher rating than Fischer"

Kramnik never got anywhere close to Kasparov's peak rating, but that didn't stop him from winning the match.

"Karpov's camp could not even get 2700chess to post it for years"

Who is in this evil Russian camp that worked so hard to make an online site give him his correct peak rating instead of keeping it below Fischer's? :-)

"Karpov is never going to beat Fischer"

You sound rather certain about this :-)

"I would listen to both Spassky and Karpov, who considered Fischer the stronger player"

Karpov said that he thought his chances of winning the match in 1975 was 40%. That doesn't say much though. Janowski was certain of beating Lasker when he lost 0-8, while Euwe thought less of his chances before beating Alekhine.

I am less sure than you and the OP, the only thing that is sure is that you can't lose any matches if you refuse to play, as Fischer did.

Karpov was stronger than Petrosian, Spassky, Larsen, or Taimanov.
http://www.chessmetrics.com/cm/CM2/PlayerProfile.asp?Params=199510SSSSS3S062745000000111000000000000010100 

"Not even disputable?" Buy a dictionary!

That was in 80s though. In 80s he was occasionally working on chess or chess960.

In 73-75, he was just travelling and reading books. Fischer joined San Antonio 72's ceremony and when he was asked about Karpov being the champion he replied "I have hardly heard of him."

I too conclude he was WILLING to play Karpov but that is different issue: if FIDE managed to make him sit on the table, he would have entered the match without preperation. And that is why I say Karpov would definitely win.

3 years of inactivity is too huge of a handicap to overcome against Karpov 75

Career-wise, inarguably.

Was Karpov 75 stronger than the Petrosian, Spassky and Larsen that were defeated by Fischer?

I would say Karpov75 was NOT stronger than the Spassky or Petrosian Fischer faced.

#46
Chessmetrics:
Karpov 1975 = 2800
Spassky 1969 = 2773
Petrosian 1971 = 2750
Larsen 1971 = 2755
Taimanov 1941 = 2750

Kramnik won his match by using Kasparov's ego against him...it was the Berlin and Kasparov's inability to stop himself from dashing himself against the rocks to prove himself right that lost that match.  Letting Kasparov beat himself was a smart play, to be sure, but not a measure of real chess skill relative to Kasparov.  Kramnik was the first WC to enjoy chess engine analysis that was stronger than his human opposition.  It's not so easy to sneak up on super GMs these days.

My statement obviously holds up...Karpov will never beat Fischer.  I'm certain of this.  How are you *not* certain of this?  Fischer is dead and Karpov will never beat him.  So it's pointless to speculate.  

Talking about Karpov winning in '75 is just what Soviet supporters do.  That's why they push Karpov stories, because they don't like Kasparov's politics.  Let it go.  There's only two chess champions that have walked away on top while completely dominating the rest of the field, and I'll leave it you to figure out what they have in common.

Fischer was a reprehensible human being outside of chess.  He was also a far superior chessplayer to Karpov. 

”Letting Kasparov beat himself was a smart play, to be sure, but not a measure of real chess skill relative to Kasparov”

Kramnik wanted to win the match, which he did, if he proved more chess skill than Kasparov is less important if we talk about winning matches. I do have a feeling though, that if Karpov had beaten Fischer, he would be said to not have proved real chess skill compared to Fischer…

”Talking about Karpov winning in '75 is just what Soviet supporters do.  That's why they push Karpov stories, because they don't like Kasparov's politics.  Let it go”

I don’t think Kasparov’s politics, or my opinion on them, are related to a hypothetical Fischer vs Karpov match in 1975, or my opinion on such a match. In 1975 I would probably have been betting on Fischer, because his top level was known, while no one knew anything about Karpov’s greatness. One did not yet known how far Fischer had fallen either, but with hindsight Karpov would probably have played better than expected. Today I would have bet on Karpov, very much doubting that Fischer would manage to finish the match. Karpov was less submissive than Spassky with regards to accepting Fischer’s requests.

”There's only two chess champions that have walked away on top while completely dominating the rest of the field, and I'll leave it you to figure out what they have in common”

They were American Heroes? :-)

”He was also a far superior chessplayer to Karpov”

That is debatable. I have both a bit behind Kasparov-Lasker-Carlsen, it’s a question of personal preference who to rank first of them with regards to greatness. Karpov is often underestimated.

I don't believe in heroes.  It's just an objective fact.

I'd take Kasparov, Capablanca, and Fischer over your trio any day.  Carlsen is a great player, but he's a little too lazy in a field of engine-reliant super GMs that rely on opening prep memorization too much.  It's an environment any "best of field" champion would thrive in.  If he pushes to 2900 while his peers are at 2780-2800, he'll be in Fischer territory.

"One did not yet known how far Fischer had fallen" is conjecture.  You can only point to his play in 1992, 20 years later...not 3.

In January of 1975 Karpov’s FIDE rating was 2705 and Fischer’s rating was 2780, the same as it had been after his match with Spassky. Having been away from chess, Fischer’s 1975 playing strength was certainly less than that. But how much less?
 
We do have a post-1975 estimate of Fischer’s strength from his 1992 match with Spassky. His performance rating in that match was 2645. What if we treat this as his basement rating for the match against Karpov? Yeah, there’s lots to quibble about here, but I did it just for fun using this calculator:
 
https://wismuth.com/elo/calculator.html
 
With Karpov at 2705 and Fischer at 2645 and with Karpov needing to be the first to 10 wins and winning by 2 (i.e., Fischer’s conditions for playing) the winning probabilities are:
 
Karpov 78% Fischer 22%
 
Karpov is heavily favored here, but to claim he would indisputably win is rather overstating the odds.
 
So what would Fischer’s playing strength need to be to back up a claim that Karpov would indisputably win?
 
At 2608 Fischer’s win chance would be about 10% and it drops below 1% around 2525.
 
Is almost 3 years away from chess enough for one of the best players ever to lose somewhere between 170 and 260 points of playing strength? That I don’t know. Any data (not opinions) available on that?

What you should look at is the home preperation and latest chess theory developments. When you are caught up in such preperation, it hardly matters IF you are active: Anand was caught in Kasparov's preperation once and he lost like a patzer. History is full of such caught-in-home-prep moments.

Fischer was practiceless for 3 years, he was just reading  history books and travelling. Look how many novelties Spassky came up with against Fischer? Karpov was even more hardworking, more hungry and most importantly: the state would have given him far more help, he would have had wider team, everything dedicated to defeat that 3-years-alein-to-chess Fischer. There was no way Fischer could survive, even if he found the proper responses to the home prep over the board, he would burn much time in which Karpov could win on time.

#51
If Fischer dropped from 2780 to 2645 after 20 years of inactivity and ageing, then we should estimate him at 2760 in 1975.

Get real.  So your premise is that someone who retires loses the same amount of knowledge/expertise in 3 years as they do in 20 years?

Okay, I was trying to take your posts at face value, but you're just trolling.

#53
Estimating Fischer at 2760 and Karpov at 2800 (January 1975 Rating list) prediction would be Karpov to win 10-6 with 21 draws.

#52

"What you should look at is the home preperation and latest chess theory developments."

Karpov would certainly have a large edge here. But large enough for a guaranteed win? I'm not so sure. One hallmark of his match against Spassky was deviation from his standard repertoire, negating much of the Spassky's preparation. Presumably he would have adopted a similar approach against Karpov.

"There was no way Fischer could survive, even if he found the proper responses to the home prep over the board, he would burn much time in which Karpov could win on time."

What's Fischer's record against strong opponents when faced with novelties?

Karpov was 2705 on the 1975 FIDE January rating list. Karpov's January 2800 rating is from Chessmetrics. The last rating they give to Fischer is 2793 in August 1974.

#57
Botvinnik played a line he had analysed for his match against Smyslov. Fischer had to think and refuted Botvinnik's analysis over the board.
https://www.chessgames.com/perl/chessgame?gid=1008417 
Keres played a queen sacrifice he had prepared. Fischer thought and refuted it.
https://www.chessgames.com/perl/chessgame?gid=1043999 

Karpov has never been rated 2800 in his entire life.