In the Lost episode "The Greater Good" we are shown how and why Sayid ends up on flight 815. Sayid was working with the American CIA trying to stop a terrorist bombing in Australia. He arranges a "chance" meeting between himself and his college roommate to try to stop him taking part in a terrorist bombing. However the CIA officers Sayid is working with are not happy with stopping his roommate from taking part in the bombing; they want a complete disruption of the cell and the recovery of the explosives that Sayid's roommates plan to use in there planned bombing.
At one point the roommate tells Sayid that he is going to be a martyr. He is scared, not because he is afraid to die, but because he believes according to the Koran killing is immoral. Acting as an undercover agent Sayid argues to his friend that killing is acceptable because it is for the greater good. According to Sayid's argument the war in Iraq is illegal and immoral and killing thousands of innocent people and a terrorist act in Australia will disrupt that county's passive acceptance of the war.
I will not deny that I have always felt that there is some legitimacy to the concept of acting in the greater good. Of course the classic example is is it acceptable for a starving man to steal food to survive. I have always agreed that the starving man was justified. However, I don't think that one life is of more value than another. Furthermore, I don't know if basic math really applies when speaking about human lives; meaning it isn't right to kill one person to save three others. As humans we have the right to save our lives but taking another, even to save another is not the providence of and individual person, group or government.
Murder is not a justification for killing. Of course, this is sadly where my personal philosophy take a bend from the major religions of this word. Christianity, Islam, and Judaism all say killing is wrong but partitioners of each of these religions justify there actions based on faith. But that is another blog for another time.