In 1956, when some of us went to Russia for the Moscow meeting on particle physics, there were discussions about this issue. Landau and his group - Ioffe, Abrikosov, Termatirossian and so on and so on - claimed that they had shown that quantum electrodynamics was self-inconsistent, which meant in the terms that Francis and I used, that our integral dx over ψ of x would converge – but this depends on ψ of x at very large x. But all you can determine from perturbation theory is ψ of x at very small x. So the work that Landau and his friends did using leading logs didn't seem to us to be convincing, so that while they might be right, that the theory was self-inconsistent, we felt they hadn't shown it at all. But it was impossible to tell that to Landau and his group, first of all because Landau never listened to anything very much, or very rarely listened to anything; but besides that there was a special feature, which was that they hated Bogolyubov. They and Bogolyubov were scientific and political rivals and enemies and… and anything Bogolyubov had done was automatically wrong, suspect, mustn't be discussed and so on. And they thought of this work as Bogolyubov's, not ours. So we were unable to raise the issue with them in our terms. Francis wasn't there actually; I did it myself, but I represented our… our point of view.