The question isn't "would killing 63 people bring world peace" it's "If you were assured of world peace by killing 63 people, would you do it." Obviously the whole notion is implausible to begin with, but that isn't the point. I think the main question here is whether you subsribe to Utalitarianism or Kant's categorical imperatives.
Someone like J.S. Mill would say that the long term benefit to society/humanity of such an action would outweigh the short-term detriments, therefore making it an acceptable deed. The action doesn't matter so much as the end result.
Motive --> Action -->
Consequence
Now if you were to look at it from Kant's perspective, he would say that the deed would be morally wrong and unacceptable because you are using the 63 people as means and not ends...a big no-no accoding to him. The consequences/results would not matter because the deed in itself is wrong.
Motive -->
Action --> Consequence
As for me personally, I still haven't decided whether I would do it or not.
