One reason Harry might not use the killing curse is that he wants to avoid the slippery slope that Mad-Eye warned of—once a wizard has used the curse once, it becomes easier to do so in the future.
Moody said the slippery slope was due to killing, not due to casting the curse, and Harry still killed the troll. Quote:
Moody shook his head slightly. “One of the dark truths of the Killing Curse, son, is that once you’ve cast it the first time, it doesn’t take much hate to do it again.”
“It damages the mind?”
Again Moody shook his head. “No. It’s the killing that does that [emphasis mine]. Murder tears the soul—but that’s just the same if it’s a Cutting Hex. The Killing Curse doesn’t crack your soul. It just takes a cracked soul to cast.” If there was a sad expression on the scarred face, it could not be read. “But that doesn’t tell us much about Monroe. The ones like Dumbledore who’ll never be able to cast the Curse all their lives, because they never crack no matter what—they’re the rare ones, very rare. It only takes a little cracking.”
You can’t want the person dead as an instrumental value on the way to some positive future consequence, you can’t cast it if you believe it’s a necessary evil, you have to actually want them dead for the sake of being dead, as a terminal value in your utility function.
Killing the troll was for the greater good so this might not count as soul-cracking murder. But then there’s also ‘giving himself over fully to the killing intention’ which might count.
Moody said the slippery slope was due to killing, not due to casting the curse, and Harry still killed the troll.
Harry also kills chickens, cows, and whatever was in that chili they serve at Mary’s Room and more. To Harry a troll isn’t people. Killing it won’t break his soul.
Are trolls sentient/sapient? Does killing one carry the same moral/psychological weight as killing a human? Cononically, they are able to comunicating using a system of grunts, though we don’t know enough about it to tell if this is a true language, or merely a call system. We also know that some trolls can understand a few human words, but so can dogs.
Even if they are sapient, it might not have the same psychological effect.
The effect of killing a large, snarling, distinctly-not-human-thing on one’s mental faculties and the effect of killing a human being are going to be very different, even if one recognizes that thing to be sapient.
If they are, Harry would assign moral weight to the act after the fact: but the natural sympathy that is described as eroding in the above quote doesn’t seem as likely to be affected given a human being’s psychology.
One reason Harry might not use the killing curse is that he wants to avoid the slippery slope that Mad-Eye warned of—once a wizard has used the curse once, it becomes easier to do so in the future.
Moody said the slippery slope was due to killing, not due to casting the curse, and Harry still killed the troll. Quote:
But it was also said:
Killing the troll was for the greater good so this might not count as soul-cracking murder. But then there’s also ‘giving himself over fully to the killing intention’ which might count.
Harry also kills chickens, cows, and whatever was in that chili they serve at Mary’s Room and more. To Harry a troll isn’t people. Killing it won’t break his soul.
Are trolls sentient/sapient? Does killing one carry the same moral/psychological weight as killing a human? Cononically, they are able to comunicating using a system of grunts, though we don’t know enough about it to tell if this is a true language, or merely a call system. We also know that some trolls can understand a few human words, but so can dogs.
Even if they are sapient, it might not have the same psychological effect.
The effect of killing a large, snarling, distinctly-not-human-thing on one’s mental faculties and the effect of killing a human being are going to be very different, even if one recognizes that thing to be sapient.
If they are, Harry would assign moral weight to the act after the fact: but the natural sympathy that is described as eroding in the above quote doesn’t seem as likely to be affected given a human being’s psychology.