Atheism is the rejection of the superstitions of our ignorant ancient ancestors, and (possibly) a determined effort to create a rational, forward looking civilization.
a.) There are no vital needs that religion meets, other than filling the pockets of shameless charlatans who reap obscene profits by undermining education and attacking scientific (physical) truth.
b.) Religion has always been the relentless enemy of human progress.
c.) "Who am I, what am I, [and] what can I know" are utterly meaningless drivel that each of us can answer for ourselves, or ignore completely if we so choose. ...meaningless word games to befuddle the naive and the ignorant.
d.) None of those questions have the least importance to people who appreciate the vital difference between objective reality and subjective mental experience.
Nobody is asking you to live without your precious God. All most atheists want is for Christians to respect the separation of Church and State and stop attempting to undermine American civilization by forcing their superstitious codswallop into our laws, government, schools, and research laboratories. Christians are clearly the enemies of intellectual development and social progress and have long been shameless parasites, greedily enjoying the many benefits of modern civilization, while contributing nothing but superstitious ignorance and relentlessly complaining about everything they do not understand.
The rising tide of atheism is not an empty rant, it's a spontaneous effort by educated citizens to keep the ignorant fools among us from destroying everything humanity has achieved since the dawn of the scientific revolution, 418 years ago. The truth is that subjective human mental experiences have absolutely nothing to do with objective (physical) reality and the physical realm is absolutely real -- contrary to 1600 years of ignorant Christian dogma. Nothing is more important than to discard the superstitions of our ignorant ancestors and to seek humanity's destiny in our future. Why can't you deluded fools appreciate that a great many human beings are simply sick and tired of living in the superstitious ignorance of the past?