Still, the contemporary quarrels between atheists and theists, like the equally fierce quarrels between the different theist religions of salvation, take place within a shared sensibility. It’s indicative, for example, that theists and atheists agree on the vast importance of what individuals believe about basic religious questions such as the existence of God; it’s just that to the theists, having the right beliefs brings salvation from eternal hellfire, while to the atheists, having the right beliefs brings salvation from the ignorant and superstitious past that fills the place of eternal damnation in their mythos. That obsession with individual belief is one of the distinctive features of the current western religious sensibility; in the heyday of the old temple cults, while acts of impiety toward sacred objects or ceremonies would earn a messy death in short order, nobody cared about what opinions individuals might have about details of religious doctrine, and thinkers could redefine the gods any way they wished so long as they continued to show proper respect for holy things and holy seasons.
The hostilities between Christianity and contemporary atheism, like those between Christianity and Islam, are thus expressions of something like sibling rivalry. Salvation from the natural world and the human condition remains the core premise (and thus also the most important promise) of all these faiths, whether that salvation takes the supernatural form of resurrection followed by eternal life in heaven, on the one hand, or the allegedly more natural form of limitless progress, the conquest of poverty, illness, and death, and the great leap outwards to an endless future among the stars. It’s precisely the absence of those common assumptions, in turn, that makes communication so difficult across the boundary between one religious sensibility and another. The gap in understanding that reduced an intelligent man like David Brin to spluttering fury at the suggestion that salvation might not be waiting for humanity out there among the stars is exactly parallel to the one that drove normally tolerant Roman thinkers to denounce the early Christians as “enemies of the human race.” - John Michael Greer