Fischer no doubt.
Bobby Fischer vs Paul Morphy

Equal motivation?
"Paul Morphy was perhaps the most accurate player who ever lived. In a set match he could beat any player alive."
- Bobby Fischer
If we are to only consider natural talent in the pursuit of fair comparison, then I am inclined to say Morphy. To be as good as he was, playing chess in the 1860's shows he possessed an enormous talent for chess. Any of bobby's talent is obscured with the leaps and bounds of improvements from when he was playing chess roughly 100 years later. That means I can't for sure have a baseline for which to judge them equally. We will never know for sure who would win if they both had equal access to the preps of whatever era , but it is sad that Morphy and countless others before him were deprived of their potential because of the lack of competition and chess theory available at the time. We will never know how much greater they could have been.

We will never know for sure who would win if they both had equal access to the preps of whatever era ,
"for sure"?
That suggests that we have a pretty good idea who would win but are not completely sure.
That just isn't true.
Truth is we will never know.
And all the opinionating and pontificating in the world is not going to change that fact.

Morphy had genius but Bobby had lots and lots of books. With all that chess knowledge in hand, Fischer would probably win 90% or more of the time.

@modestandpolite: some of us WILL opinionate and obfuscate, grandstand and pontificate, cajole and browbeat, filibuster and gerrymander, deduce and induce, enlighten and clarify, curse and vilify, praise and mollify, just to prove Fischer was THE Best player ever.

And since he had the most powerful chess brain and was a naturally very speedy player he would only have to avoid a losing line, survive opening prep and then outplay his weaker opponent.
But if we're talking an equal playing field then Morphy wouldn't even get caught out on memorized opening prep.
And on the subject of memorization, do you think that Hikaru Nakamura would be capable of memorizing the entire legal code for the state of Louisiana? Nakamura can't even speak Japanese FFS.
That suggests that we have a pretty good idea who would win but are not completely sure.
That just isn't true.
Truth is we will never know.
And all the opinionating and pontificating in the world is not going to change that fact.
Right, I did not mean to say for sure, that was unintended and a contrast to what I think, which is that we will never have a way of knowing. We can only speculate.

Lets just break it down; Fischer read over a thousand chess books. He also played thousands of solo games and annotated the games played by both himself and other grandmasters ten thousand times over. Morphy lived in a time where positional play didn't exist and there were only opening books. In that time, Morphy lost at least 1 of the games he ever played, even when he was nearing his peak as the greatest player of the 19th Century. Fischer would win, fair and square
Fischer. Morphy was rated like 2400 by todays standards
2400? Woah man. Morphy was insanely talented beyond comprehension. If you don't think he was better than fischer you would still have to concede he would definitely be at the top 100 in bobby's time. Combine that talent with newfound chess knowledge for him to tune into his game and the man would be unstoppable!

Fischer. Morphy was rated like 2400 by todays standards
2400? Woah man. Morphy was insanely talented beyond comprehension. If you don't think he was better than fischer you would still have to concede he would definitely be at the top 100 in bobby's time. Combine that talent with newfound chess knowledge for him to tune into his game and the man would be unstoppable!
But he died, so, yeah, that's nice.
Fischer. Morphy was rated like 2400 by todays standards
2400? Woah man. Morphy was insanely talented beyond comprehension. If you don't think he was better than fischer you would still have to concede he would definitely be at the top 100 in bobby's time. Combine that talent with newfound chess knowledge for him to tune into his game and the man would be unstoppable!
But he died, so, yeah, that's nice.
Lucky for fischer

Fischer. Morphy was rated like 2400 by todays standards
2400? Woah man. Morphy was insanely talented beyond comprehension. If you don't think he was better than fischer you would still have to concede he would definitely be at the top 100 in bobby's time. Combine that talent with newfound chess knowledge for him to tune into his game and the man would be unstoppable!
But he died, so, yeah, that's nice.
Lucky for fischer
Pha!

Top 50 Strongest Ever:
- 1: Ponomariov
- 2: Euwe
- 3: Alekhine
- 4(tie): J. Polgar
- 4(tie): Karjakin
- 5: Giri
- 6: Kasparov
- 7: Carlsen
- 8: Anand
- 9: Fischer
- 10: Tal
- 11: Petrosian
- 12: Botvinnik
- 13: Lasker
- 14: Capablanca
- 15: Smyslov
- 16: Korchnoi
- 17: Keres
- 18: Morphy
- 19: Sokolov
- 20: Steinitz
- 21: Stein
- 22: Staunton
- 23: Aronian
- 24: Karpov
- 25: Nimzovich
- 26: Shirov
- 27: Serper
- 28: Topalov
- 29: Rubenstein
- 30: Spassky
- 31: Chajes
- 32: Larsen
- 33: Schlecter
- 34: Junge
- 35: Bogoljubov
- 36: Flohr
- 37: Bronstein
- 38: Polguevsky
- 39: So
- 40: Caruana
- 41: Vachier-Lagrave
- 42: Svidler
- 43: Nakamura
- 44: Philidor
- 45: Harikrishna
- 46: S. Polgar
- 47: Nepomniachtchi
- 48: J. Xiong
- 49: Adams
- 50: Ivanchuk
Who would win a battle with both of them alive? Let me know who would win.