The current heated "(monotheist) believers vs. atheists" threads tends to overlook, imo, this rather commonplace but relevant issue: how modern Atheism continues (and thus is tributary to) a line of religious, philosophical and scientific thought which runs from ancient polytheism through monotheism, both in Greek and Jewish traditions (which are the two main sources of Western culture).
In the Greek-speaking world, Homeric-like polytheism went out of fashion, and although political authorities stood for the conservation of popular worship of the gods (atheism being a capital offence, ask Socrates), an intellectual monotheism came to the fore, especially in Platonic tradition, along with more or less "underground" forms of early atheism (Democritus, Epicurus).
In Judea, for mainly political reasons ("one god, one temple, one priesthood, one king") the "Deuteronomistic reform" of the 7th century BC promoted the active rejection (1) of all other gods than Yhwh, and (2) of any representation of Yhwh himself, henceforth branded as "idolatry". It also (3) reinterpreted most "natural" features in older Israelite religion (linking Yhwh, just as Baal, with the cycle of seasons, especially the rain and dry seasons, vegetal and animal fertility) into historical (or pseudo-historical) celebrations: the feast of spring became the celebration of the national foundation in the exodus from Egypt, etc. (4) The development of a doctrine of creation, increasingly construed as creatio ex nihilo -- mere "fabrication" of the world out of nothing instead of the older theomachy (struggle between the gods) wrestling for order out of chaos contributed to emptying "nature" of its numinous, sacred or divine presences: the sun, the moon, the stars, vegetables, animals and humans became mere "objects," vessels designed and made by a master craftsman, but devoid of intrinsic divinity. This practically paved the way for a practically materialistic approach of the universe of phenomena.
In the wake of Jerusalem's fall and Babylonian exile which quickly followed, Deutero-Isaiah introduced monotheism proper by denying the very existence of any god besides Yhwh: as a result Yhwh was no longer "a god" but "God". There were, of course, a number of resurgences of repressed polytheism within monotheism, with the post-exilic development of angelology and demonology linked to the diversity of "good" and "bad" phenomena. The "invention of the devil" combined a theoretical monotheism with practical dualism. Christology reintroduced plurality into the divine, especially with the Trinity doctrine. But the critical, negative trend which rejection of polytheism and "idols" had started could not be easily stopped. Theology, linking the Greek philosophical tradition with the Jewish heritage, kept on sweeping the "pluralistic" and "anthropomorphic" aspects of "God" under the carpet in favour of an increasingly abstract notion of God as "first cause". In the classical age Deism was naturally thought of as the "theism of reason" until political freedom allowed the clear expression of materialism and atheism (which I think were not new, but had been haunting the system all along).
In short, my point is: the roots of atheism, just as of monotheism, reach deep in our history of thought, and especially in the Bible itself. Monotheism came up with the denial of gods. Atheism actually follows up what was started with monotheism by denying one god more -- the remaining "idol" as Nietzsche put it. The process of denial (aka criticism) is common to both.
I think the monotheistic vs. atheistic debate might be greatly improved if both parties acknowledged what they have in common. Not to say that what they have in common shouldn't be, in turn, questioned (as the so-called "post-modernist" perspective calls for).
Comments?