No rational atheist claims to have proof that there is no god. This seems to be the most common fallacy about nonbelievers. It is not logically possible to prove that a thing does not exist. We can however critique the evidence that theists offer, and we claim that theists offer no credible empirical evidence for the existence of their deity, who, they tell us, when all their other arguments are proven false, can be known only through faith. Unfortunately, on planet earth, faith is a feeling, and feelings are not facts. What religion offers looks suspiciously like a wish fulfillment fantasy, a very human yearning for how life should be, but is not. In the intellectual childhood of our species, that was enough; but today it is not.
Religion's stories of ancient holy men and gods who intercede in the human realm are very powerful. These stories reflect deep-seated symbols and expectations about how the world works, about the limits of the human condition and how they may be transcended. At the same time they forge the cultural and communal identities that are so important to human emotional well-being.
Yet the fact remains that the Judaeo-Christian-Islamist religion's worldview is, in a word, false. We are not orphans on a hostile planet ruled by invisible spirits. We were not placed here at the caprice of an all-powerful sky god who can be influenced through magical thinking to intervene in our lives. And there is no agency that will allow us that ultimate human desideratum, to continue to have consciousness after we die.