This detail doesn't matter. He's still computing a tiny nonzero probability that is only zero in the limit. We came up with other examples of tiny nonzero proba

This detail doesn't matter. He's still computing a tiny nonzero probability that is only zero in the limit. We came up with other examples of tiny nonzero probabilities that are zero in the limit that can lead to the wrong conclusion, such as saying that 42 doesn't exist. Feynmann's argument is clumsy and wrong. This kind of approximation is ok for a physicist but it doesn't work for mathematics.