Why? That's the question I had while reading this part, a question that was never really answered even after the conclusion of this story. Why did Meursault kill the Arab? He doesn't even know the answer himself. He knew it would accomplish nothing, he knew he could have walked away- so why? Why did Meursault kill the Arab?
It's a tough question- nobody really knows why. And so then the question must be, what was the point? What was this meant to show? What does this mean? And there, we can find an answer.
The author of The Stranger, Albert Camus, had a widely-known belief in the existential philosophy, one that says that nothing can rationalize human existence and there is no answer to the question of "why am I?" This philosophy, at its core, says existence precedes essence. Meursault is the character who exists, but feels no meaning to his existence, no essence. He knows death will come to him and all others one day, and he therefore doesn't care when that time is. He simply lives; he doesn't feel meaning to his life.
And maybe that's the whole point- that the meaning of his killing was to show that it had no meaning at all. He knows life will end one day, for him and the Arab. He sees no reason to allow them to live longer if they will one day die either way- in his view, there is no meaning in the life they'd otherwise live.
It's a rather depressing outlook, in my opinion, to think that life has no meaning. I do believe that if one has that outlook, as Meursault did, their life will indeed have no meaning. But maybe if we think ourselves to be meaningful, maybe if we believe that existence is not absurd and irrational but instead real and true, and if we act differently from Meursault in a situation like this- maybe then, we'll have meaning.
That's the answer to the question of "why?” Meursault had no reason, he saw no meaning. He knew death would come either way, and didn't care that he was allowing it to come sooner. Albert Camus is showing us the absurdity of the human existence, that there is no answer for the question of "why do I exist," since, by the time our individual lives come to an end, we will die.
But I disagree. I may be naive and foolish, but I can’t live with the thought that life has no meaning. I’m not like Meursault. When I’m standing, gun in hand, the barrel pointed at the head of another man, I see something. I see all the things that can happen in life, and I see the meaning life really has. Unlike Meursault, I lower the weapon. I walk down the hot, red shore in the other direction.