The best argument atheists have against the existence of God is known as the problem of evil. How can a God that is both all-good (omnibenevolent) and all-powerful (omnipotent) allow unjust suffering in the world? This question alone has driven millions from the faiths. Philosophers and theologians have wrestled with this question for centuries, some offering better answers than others.
One of the most interesting responses to the problem of evil came from Milton Steinberg, a twentieth century American rabbi and theologian. He argued that if theists must be held accountable for answering such a question, must not atheists also be held accountable for answering an equally difficult question: why is there something as opposed to nothing? Where did everything come from? Atheists have an equally difficult time answering this question.