We don't know how brains work. In Trek, such things can move, float around, change bodies, even exist in the ship's computer
i would argue that sometimes, it's the original consciousness, other times a copy. In the case of Picard's resurrection specifically, why can't he simply be a biodroid copy of Picard?
Indeed. I submit if Sargon and his ilk can go in and out of bodies, and Ira Graves can do similar Picard is just Picard.
I just watched an ep of Voyager where Harry and Chakotay get turned into energy beings on the holodeck and then back to themselves again
In real life? Probably. In Star Trek? Sorry, but Star Trek has always bought into the mind/body dualism thing. It may not be realistic, but it is an established fact of canon that subjective consciousnesses can be transferred rather than destroyed and copied. Says who? Because there is no such indication in the episode, and because such a sequence of events would defy the clear thematic intent of the creator of Jean-Luc experiencing resurrection and new life.
But mind being something simply hardwired into the brain organ (or, as is currently fashionable to think, to the entire body and indeed to the social network around it, if not to every single tree and pebble ever encountered to boot) would not preclude copying.; if anything, mind being fundamentally physical would best facilitate that. The exact mechanism of the copying would then have to be considered to establish whether destruction also happens - and it's quite easy to see the copier being destructive for all sorts of practical reasons even if in theory the original could survive. Timo Saloniemi
I'm inclined to think that consciousness is non-material in Star Trek or at the very least transferable given what we've seen with Vulcans, psychics, and the transporters. Besides, mind-body dualism is something that has been making a comeback even if not in the traditional religious sense.