i asked my brother this question and he answered

"you'd better kill yourself! but the only way that could be true is when cops kill a criminal to save others lives"

If someone is trying to kill me, you'd better believe I'm going to try to kill them first. I'd say killing them as a last resort is okay because it saves me.

It depends who you are killing and who you are saving, if your trying to kill and armed mugger to save your girlfriend/wife then yes.

It largely depends on what standard you qualify killing to save another as "okay", but personally the only standard I go by is reason and in this case, there's no real answer.

It comes down to the specifics -- and yes, some people are 'worth' more than other people.

Using a utilitarian moral framework - if saving the other brings about more happiness than allowing them to be killed, then sure it's okay. As a result, you can conclude that those who bring about the most happiness are the most important.

I would kill any stranger to save my mother, but I would never kill my mother to save a stranger

Here is a good example of this scenario. A woman is giving birth to a baby. The doctor realizes the woman's blood pressure is spiking. There are two choices

1. The doctor terminates the birth and the woman survies (baby dies)

2. The doctor continues the birth and the baby survives (woman dies)

Who do you choose? Is this not killing one to save another?

I would save the baby if the baby has other family. The woman if the baby would be orphaned.