"Whether there be other good or not, the good of the present life is good, and it is good to seek that good...Individual good attained by methods conducive to the good of others, is the highest aim of man, whether regard be had to human welfare in this life or personal fitness for another. Precedence is therefore given to the duties of this life."
One of the tactics proselytizers use to try to convert nonbelievers is the appeal to fear. What if you're wrong? What if it turns out there really is a god and you've lived your life on the assumption that there isn't?