I just finished watching the show and am still unclear on how uploading works.
Disregarding the second half of the last episode – which I don't think anybody is really meant to understand – the one thing that seems inconsistent is how Stephen was uploaded. He was already dead when he was, everyone else had to be uploaded when they were still alive because their neurons had to be firing.
Is it the fourth ridge on Holstrom's brain that makes this possible? Can other people be uploaded after they die? What's going on here?