The contention that there is no God and that religious faith in such an entity is a consequence of man's imagination or gullibility.
It has been argued that virtually everyone is an atheist as few people profess to believe in all the gods or other divine personalities devised by man. More conventionally, the atheist denies the existence of God as perceived by Christians and adherents of other major world religions, pointing out the lack of material evidence for such a being and the dilemma posed by the idea of a loving God permitting suffering and other evils to continue in the world.
Atheists frequently point to the apparently ever-widening gulf between modern science and religious faith, and sometimes claim that God has become 'the god of the spaces in between' known scientific facts.
As science advances, so many atheists argue that God's natural territory is decreasing and that 'blind' faith is increasingly untenable and even immoral when the acceptance of such ideas depends increasingly upon the denial of reason.
J Monod, Chance and Necessity (Oxford, 1982)