1961… yes, that was the year that Goldberger and Blankenbecler pointed out that particles of higher and higher angular momentum seemed to lie on Regge trajectories that were quite straight. Again plotted versus mass squared for bosons and versus mass for fermions, and that the odd and even trajectories seemed to be almost degenerate–although they don't have to be by any rigorous principle. I wonder whether–I still wonder, I have wondered all this time and I still wonder—whether the straightness of those trajectories and the accuracy of the first order mass formula for SU(3) aren't somehow related to each other; both are a little bit surprising. In any case, I accepted both field theory and the dispersion theory program of calculating amplitudes on the shell, by means of dispersion relations, generalized unitarity and crossing relations. In fact I had introduced that idea myself back in 1956. So I didn't have any quarrel with the program of Geoffrey Chew and his associates, except for the language that he used to describe it. I thought it was very good to look at self-consistent formulae… self-consistent formulae for scattering amplitudes and so on. Later on I objected to the use of a very, very, very small number of states in these calculations; beating to death with false accuracy one or two states, instead of treating a vast number of states approximately. But that's much later; that's toward the end of the  ‘60s.

 In the meantime, in 1961, I was intrigued by the Regge trajectories and I worked on them a lot. I worked on the consequences of the complex angular momentum plane analysis for high energy scattering, and high energy reactions in general. And a lot of my associates at Caltech were interested in it. I invited Steven… Steven Frautschi, to come to Caltech, he's still there in fact. But I… I didn't accompany my enthusiasm for this work with a rejection of the concepts of quantum field theory. I was gloomy about finding a correct Lagrangian. I put that off into the distant future, although, as you know, as we discussed before, I did have the idea that both the strong and the weak interactions would be connected somehow with Yang-Mills theory. But the model that I used for abstraction, which I knew was wrong but was a definite Lagrangian field theory, was the one with three fermions of spin a half and a single neutral vector boson. And the three could be neutron, proton and lambda, and then later on of course situation was much…much improved by taking up, down and strange quarks. However the… there was not a direct connection between the work on symmetries and abstraction from quantum field theory models on the one hand, and the work on the complex angular momentum plane on the other. But I did a lot of… a lot of research on the complex angular momentum plane–much of it very technical. For example; while I was in Geneva I worked out the so-called sense and nonsense of poles and all of that kind of thing; things involving more than two particles, things involving complicated… complicated situations that can arise when the spins are taken into account.