I seem to remember Willow explaining it when she was putting together the resouling spell. I can't remember the details, but someone should be able to be more specific.

I thought any soul would do. Like an organ transplant without all the rejection issues.

Or at least different rejection issues.

I don't think so, otherwise, they wouldn't have been so careful when they needed to turn Angel into Angelus. It wouldn't have been a big deal when the soul disappeared, they could have just called another one.

plus, according to Joss mythology the soul is what makes the person because when it's gone there's "nothing" of that person left.

Maybe calling a soul is the tricky part, not finding the same soul.

Also, I thought at some point someone said something like*, "Spiky got a soul" and not "Spike got his soul back." I could be wrong.

• (how's that for vague)

plus, according to Joss mythology the soul is what makes the person because when it's gone there's "nothing" of that person left.

Which made the whole Illyria destroying Fred's soul all the more devastating. I have no idea if they retconned this in the graphic novels.

I think after Spike passed all the tests the demon-guy said "I will return (restore?) to you- your soul."

I'm pretty sure that almost anything said about souls on either show was contradicted later. For example:

according to Joss mythology the soul is what makes the person because when it's gone there's "nothing" of that person left.

We see a person with no soul in "I've Got You Under My Skin."

So mostly I believe the ideas I like best without worrying about consistency too much.

according to Joss mythology the soul is what makes the person because when it's gone there's "nothing" of that person left.

I'm pretty sure that almost anything said about souls on either show was contradicted later. For example:

Plus, canon in BTVS S1-3 held* that when the person is vamped, the demon takes over, and the vamp is nothing like the person was in life, but we see later that that's more or less handwaved away, based on what we saw of Liam and William the Unbloody.

*(I know it was in Dopplegangland that Willow objected to skanky, kind-of-gay!vamp!Willow, and Buffy said that a vamp is nothing like the person was in life, and Angel started to contradict that but then trailed off. [Undoubtedly to keep from making human!Willow feel skanky and kind of gay.]

So I assume that that was the point where canon got a little dodgy, with the good guys still believing the lore about the vamp being nothing like the person, but we start to see that the vamps know that ain't necessarily so. Which makes sense, really, because prior to Angel, it's not like the Watchers/Slayers/good guys actually got to know any vampires, so of course they would believe the lore.)

good point, Steph.