Albert Camus' The Rebel is a book-length essay arguing for the absurdist philosophy and the necessity for a revolt against meaninglessness.
Camus' absurdist philosophy basically claims that life holds no intrinsic meaning. Therefore, no personal decisions, private convictions, or religious faith can suffuse our existence on this earth with any sort of purpose or significance. In fact, Camus characterizes the human tendency to find meaning in life as a senseless undertaking. In The Myth Of Sisyphus, Camus' Sisyphus clearly illustrates the futility of all life: the hero is condemned to an eternity of slavish labor, an undertaking which rewards him with failure every single day.
Therefore, absurdist philosophy holds that the only way to combat the meaninglessness of life is through revolt; to confront the powerlessness of life and the certainty of death becomes for the absurdist, the only way to craft meaning out of futility. In that vein, Camus questions whether suicide or murder should be admitted as legitimate revolts against the futility of life.
By the same token, if we deny that there are reasons for suicide, we cannot claim that there are grounds for murder. There are no half measures about nihilism. Absurdist reasoning cannot defend the continued existence of its spokesman and, simultaneously, accept the sacrifice of others' lives. The moment that we recognize the impossibility of absolute negation and merely to be alive is to recognize this-the very first thing that cannot be denied is the right of others to live. (From The Rebel).
According to his argument above, Camus argues that every practicing absurdist should not succumb to the weakness of suicide as a solution. Instead, he/she should live life to the fullest and attempt to fashion an existence that accords the greatest pleasure. Camus asserts that one can do this while accepting that insignificance need not define one's will to exist. This is the kind of revolt Camus supports. As suicide would effectively end any rebellion against the meaningless of life, Camus did not view it as a valid option.
As such, Camus also viewed murder as a way to deny others of this ability to revolt or rebel against the futility of life. In this, Camus' reasoning is sound. Camus warns that nihilism may exact a price the world may not be prepared to accept.
...metaphysical collapse often ends in total negation and the victory of nihilism, characterized by profound hatred, pathological destruction, and incalculable death.
Here suicide and murder are two aspects of a single
system, the system of a misguided intelligence that prefers, to
the suffering imposed by a limited situation, the dark victory in which heaven and earth are annihilated.
Camus cites the example of Hitler during WWII. Convinced that his reinvention of German society through mass murder would ensure German superiority and renew national pride, this madman unleashed a terrifying spectacle of bloodshed upon the world unheard of in his time. Therefore, Camus soundly rejects suicide or murder as valid alternatives for revolt against the aimlessness of human existence.