There's a debate about who was the greater physicist: Feynman or Gell-Mann. Here's a sample:
i) Let's begin with the mystique of genius. Since atheists don't believe in God, genius is the next best thing to God. Human genius is about as close as atheism will ever get to godhood. There's a tendency, therefore, to treat a scientific genius or reputed genius (e.g. Hawking) as an oracle.
ii) In comparing Feynman and Gell-Mann, one question is the level of the comparison. Are we asking which one was the smarter physicist or the greater physicist?
I think some people find Feynman more intellectually impressive. Although Gell-Mann is brilliant, you can see the gears moving. HIs achievements are clearly the result of hard work.
By contrast, what comes hard for Gell-Mann seems to come easy for Feynman. With Feynman, it's more like intellectual play. Less effortful. Less methodical.
iii) Apropos (ii), Feynman seems to have a more versatile intelligence than Gell-Mann. Feynman comes across as a brilliant man who happened to be a physicist. That was his chosen field. But it's easy to imagine him excelling in many other fields hd he put his mind to it.
There are people who achieve great things by discovering the one thing they are great at. They'd be second-rate at anything else. They don't happen to be great at what they do. Rather, that's their niche. But Feynman had a more flexible intelligence. He's more like John von Neumann in that regard.
iv) But there are tradeoffs. There's a piecemeal quality to his achievements. The parts are greater than the whole. He didn't have the kind of sweeping, penetrating insight that enabled him to produce a broad, deep, powerful theory like Relativity.
v) It may also be that he came on the scene a generation too late. Had had been born a generation earlier, he might have been one of the pioneers of quantum theory.
vi) Then there's Gell-Man. His achievements lie in the realm of particle physics. But that's hard to assess, because it's hard to say whether some of those theories represent a genuine insight into the inner workings of nature.
To a great extent, particle physicals deals with unobservables. Theoretical entities. Posits.
Now, these have some basis in reality. If we assume that events have causes, then even if the cause is undetectable, it's rational to infer an underlying cause from detectable effects.
The question, though, is how many layers down does it go. Beyond a certain depth, you can't say what is producing the upper layers.
For instance, when I was a young boy my mother used to buy L'eggs stockings. These came packaged in plastic eggshells.
I used to put marbles in the eggshells and roll them across the floor. I'd study the direction and wobble depending on how many marbles were inside, or the size of different marbles inside. The pattern would change according to the size or number of marbles inside.
It's like "hidden variables." You can't observe the marbles, but you can detect the marbles by how they affect the trajectory. That's not a hollow shell. There must be something inside that's producing that wobble or trajectory. And it would be possible to formlate a mathematical description of the motion.
But here's the catch: if physical reality is composed of marbles inside marbles inside marbles inside marbles, then there are too many possible constituents or possible combinations to infer the ultimate constituents or ultimate combination from what's observable or detectable. Are the "elementary particles" we think we can detect truly fundamental, or the result of something more elementary? Are these the building-blocks of reality, or are they composites of something even smaller? Is Gell-Man's Eightfold Way a genuine window into subatomic reality, or just an elegant classification scheme?