Oppenheimer's opinion of Feynman seems to have vastly diminished after the Shelter Island and Pocono conferences. According to Dyson [1]:
“When after some weeks I had a chance to talk to Oppenheimer, I was astonished to discover that his reasons for being uninterested in my work were quite the opposite of what I had imagined. I had expected that he would disparage my program as merely unoriginal, a minor adumbration of Schwinger and Feynman. On the contrary, he considered it to be fundamentally on the wrong track. He thought adumbrating Schwinger and Feynman to be a wasted effort, because he did not believe that the ideas of Schwinger and Feynman had much to do with reality.
I HAD KNOWN THAT HE HAD NEVER APPRECIATED FEYNMAN, but it came as a shock to hear him now violently opposing Schwinger, his own student, whose work he had acclaimed so enthusiastically six months earlier. He had somehow become convinced during his stay in Europe that physics was in need of radically new ideas, that this quantum electrodynamics of Schwinger and Feynman was just another misguided attempt to patch up old ideas with fancy mathematics.”
[1] Dyson F. Disturbing the Universe. Henry Holt and Co, 1979 ISBN 9780465016778.
This quote and an earlier one I made are from Oliver Consa's 2020 paper: "Something is rotten in the state of QED".
“When after some weeks I had a chance to talk to Oppenheimer, I was astonished to discover that his reasons for being uninterested in my work were quite the opposite of what I had imagined. I had expected that he would disparage my program as merely unoriginal, a minor adumbration of Schwinger and Feynman. On the contrary, he considered it to be fundamentally on the wrong track. He thought adumbrating Schwinger and Feynman to be a wasted effort, because he did not believe that the ideas of Schwinger and Feynman had much to do with reality.
I HAD KNOWN THAT HE HAD NEVER APPRECIATED FEYNMAN, but it came as a shock to hear him now violently opposing Schwinger, his own student, whose work he had acclaimed so enthusiastically six months earlier. He had somehow become convinced during his stay in Europe that physics was in need of radically new ideas, that this quantum electrodynamics of Schwinger and Feynman was just another misguided attempt to patch up old ideas with fancy mathematics.”
[1] Dyson F. Disturbing the Universe. Henry Holt and Co, 1979 ISBN 9780465016778.
This quote and an earlier one I made are from Oliver Consa's 2020 paper: "Something is rotten in the state of QED".