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human
[Harry Potter] Why can't dead people be brought back to life, while transfigurating into an inanimate object and back was?

We saw in the movies, that you can turn animals and other living creatures into inanimate objects, like trinkets, and turn them back into the animals they were before. Yet, in this inanimate object form, they are basically dead, since a trinket isn't a living creature, but you can still turn them back into their former self, which means you basically take a living creature, kill it with the transfiguration spell and then bring it back to live.

And if you can do that, why can't you bring back people and animals that died in other ways, like from the Kedavra spell. Or asked differently, when Dumbledore dies, what stops Harry from turning his corpse into a rock and then back into a living Dumbledore?
gpt
Dumbledore's soul would move onto the afterlife, so if you did manage to make a technically alive Dumbledore, it would be a soulless husk without any of the personality of Dumbledore. 

You could turn Dumbledore's corpse into some sort of magically animated object like an Inferi, but it wouldn't return his magic or personality in a meaningful way. 

We have seen that some very rare magics can return spirits of the dead from the afterlife, so if you can do that you might be able to bind their souls back into their bodies somehow. This necromancy was not expanded on in the Harry Potter books, as they were not written from the perspective of Voldemort.