A quick note.
At the end of part 3 of the Discourse, Descartes returns to philosophy prematurely because, contra his solitary practice of the method, he hears a rumor that he has completed his philosophy.
How these are tied together with Descartes (obviously doubtful) proofs of soul and God are not clear to me at this point. But that this larger frame is needed to grasp their significance is fairly clear .