He states that acceleration is not the reason for the time difference
between the twins; instead, the reason is in different paths in space-time.
However, he continues and says that taking a different path requires
acceleration in this scenario. This seems valid to me. What do you think?
All this was motivated by a philosopher of physics called Maudlin, who
claimed that Feynman's explanation on the twin "paradox" in terms of
acceleration was completely wrong. Here is a rebuttal of that claim: https://arxiv.org/pdf/1807.02148.pdf.