Differing answers to two fundamental questions underlie the theist and atheist worldviews:
- The question of ontology: what exists
- The question of epistemology: by what method(s) can we gain genuine knowledge of what exists?
As to ontology (what exists?), atheist and theist (and everyone but the solipsist) grant that the natural world exists. The dispute arises about whether anything exists beyond the natural world, i.e., a supernatural world of God (or gods), demons, angels, souls, etc.
As to knowledge of the natural world (epistemology), atheists and most theists agree that science gives us genuine knowledge (although some theists dispute the science on evolution, the age of the Earth, and other questions).
As to knowledge of the supernatural world, atheists deny the supernatural world exists and therefore do not believe any method can give genuine knowledge of it. Believers venerate sacred books which, they claim, contain genuine knowledge of the supernatural as revealed by prophets, saints, seers, mystics, and, sometimes, by an earthly incarnation of God himself.
To begin our resolution of the theist/atheist dichotomy we must first decide what ontology and epistemology to accept.
We accept science's ontology.
Science's ontology—i.e., the scientific worldview—includes the natural world, but does not include the supernatural, which science leaves to religion. In science's view, all the events and forces that influence the universe arise from within the universe, and have natural explanations. Because the scientific worldview contains only natural entities and phenomena, scientific explanations may contain only natural causes, not supernatural ones. Thus, science explains the cause of a disease as a virus or bacteria, not sin or demons. Similarly, science explains why planets revolve around the sun by gravity and inertia, not the will of God.
Scientists call their practice of excluding supernatural factors "methodological naturalism". Methodological naturalism avoids explanations that contain supernatural factors and it offers no opinion as to whether or not the supernatural exist. (In contrast, ontological naturalism positively affirms no supernatural entities exists.)
We accept science's epistemology.
We accept science's way of knowing—the "scientific method"—as well as the body of knowledge science has uncovered about the natural world.
Accepting science's worldview and way of knowing seems to put us in the atheists' camp in that we make no use of the supernatural, or of any "revealed" scripture. But we cannot do otherwise without favoring one religion over another, because religions have various views of the supernatural (e.g., heaven/hell vs. reincarnation) and because religions often deny the inspiration of other religions' scriptures. Because we cannot accept as valid all world scriptures, such as the Torah, Bible, Koran, Vedas, Upanishads, Tipitaka, Tao Te Ching, etc., we remain silent concerning their validity and employ none of them as a source of knowledge.
Accepting science's ontology and epistemology justifies the use of the word "science" in our title but how can we justify the use of "theology", natural or otherwise? To do theology mustn't we allow ourselves to use the word "God"? And doesn't our worldview rule out use of that word?
Not if we can validly define in our worldview what we mean by "God", which we attempt after discussing monism, dualism, and a few philosophical terms.