I'm not sure how you can say that it is hard to say what Fischer thought and then say he "certainly never wanted to play them."
I've never bought in to the argument that someone would spend there lives with the sole purpose of being the best at something and then be afraid to play. I'm not a member of the Fischer fan club but I don't think cowardace was one or his faults.
That he didn't want to play seems rather obvious since he chose not to play (in 1992 he wanted to play Spassky and did it so he could of course have played others if he had wanted to), it's the reason why he didn't want to play that is harder to know. Matches against stronger opponents all fell through (not only the one against Karpov, but Korchnoi, Polgar, Anand, and several others before that). To me it would make more sense if someone that spent his whole life with the sole purpose of becoming #1 would get afraid of playing after that goal is reached, rather than someone with a more relaxed attitude like Tal.
If I'm not mistaken, the concensus among chess experts of the time was that Fischer would have beaten Karpov with ease...If there were other opinions (from relevent experts) I don't recall seeing them.
Few experts would predict the World Champion to lose against a comparatively untried challenger (like in Alekhine-Euwe 1935 or Kasparov-Kramnik 2000), but Fischer had stopped playing already in 1972 while Karpov had his best results that far in 1973-74 and was steadily improving. It would have been a much more difficult match for Fischer than the one he won 12.5-8.5 against Spassky. What Fischer thought is hard to say, according to others he had a very low opinion of Karpov as a chess player (as well as of Kasparov), but he certainly never wanted to play against them so maybe he was just trying to convince himself about how much better he was.
I'm not sure how you can say that it is hard to say what Fischer thought and then say he "certainly never wanted to play them."
I've never bought in to the argument that someone would spend there lives with the sole purpose of being the best at something and then be afraid to play. I'm not a member of the Fischer fan club but I don't think cowardace was one or his faults.