We discussed a lot with Enrico; the pion nucleon scattering, his analysis of it in terms of phase shifts,  the presence, or absence of a resonance. He didn't like the resonance; in fact I don't think till his dying day he believed in a resonance. He favored a phase shift solution in which the phase shift didn't go through ninety degrees. And it took one of his students talking with Hans Bethe or a student of Hans Bethe, to discover that there was another phase shift solution that described the experiments equally well and where…in which the phase shift in the 3-3 state, the 3 halves 3 halves state actually did go through ninety degrees and produce a resonance. But of course that resonance had been expected for many, many, many years. In strong coupling it had been predicted by Pauli and Dancoff back in 1942, and then Keith Brueckner had made himself famous by doing some intermediate coupling calculations in the non-relativistic version of the pseudo-scalar meson theory, and showing that you would get a 3-3 resonance there. So we had a lot of practical discussions of that kind that were very educational and of course isotopic spin conservation was being confirmed further, if it needed further conservation… further, yes, further, sorry, if it needed further demonstration, in Fermi's… the experiments that Fermi and others were doing on the pion nucleon scattering. And we devoted a good deal of time to discussing symmetries and as I mentioned a little while ago, that was one way in which I felt it was possible to make progress, important progress on understanding what was going on without attempting something too ambitious–namely writing down the ultimate theory. Symmetry was, exploring symmetry was, one way to do that.