An overview of the argument against the claim "God is real"
First, I apologize in advance for the repetition that's necessary for this post.
Second, a review of the terms and shorthands I use as a convenience:
GOD = the totality of all possible definitions of God or gods
God = a monotheistic god, although I often use this rendering as shorthand for "God or gods"
god = any of the gods in a polytheistic or henotheistic system
anchored concept (AC) = a concept grounded in what we know about the world (e.g., black holes as a consequence of the known laws of physics)
unanchored concept (UC) = a concept which is not anchored in what we know about the world, such as the undetectable dog that moves my glasses
nonsense object (NO) = a hypothetical thing which by definition cannot exist, such as a boiled invisible pink ice cube, or a circle with corners
unknown unknown (u2) = things which we truly have no ideas about whatsoever, like utterly unknown and unthought-of things which may (or may not) exist in unexplored regions of the deep sea or beyond our light cone in the far reaches of the universe (note that not all things which may/not exist in these regions are u2's -- for example, p-branes outside our universe are anchored concepts since they are theorized on the basis of what we do know about our universe and have defined qualities)
Resolved: The claim "God is real" has no possible truth value, because the statement will always prove empty, nonsensical, contrary to fact, redundant with purely material claims (i.e. not God), or mere Humpty Dumptyism.
It is important to note at the outset that the God hypothesis (GH) is much like phlogiston. That is, it arose within, and depends upon, a set of assumptions about the world which have proven false.
Some theists (as well as atheists) prefer to avoid any discussion of the mythical origins of the GH because, they point out, mythic origins do not prove falsity.
And while it is true that mythic ideas may coincidentally prove true -- for instance, the idea that there were inhabited lands across the ocean to the west of Europe and Africa -- we must deal with the mythic origins of the GH in order to distinguish it from ACs such as black holes. We have already seen on this thread the attempt to defend God by comparison to ACs such as black holes, despite the fact that God is a UC.
History has not been kind to the magical world view which made the GH appear plausible. At every turn, God and the mythic world view have lost -- heavenly lights are not divine beings, an anthropomorphic creator is not needed to explain universal origins or consciousness or life, geographic features are not the result of wars among the gods, etc etc etc -- so that today the only (only!) progress being made in the investigation of our world is being conducted within a framework that makes absolutely no reference to God, gods, the soul, or magic.
Not only is there no evidence for God, but there is no need -- indeed, no room -- for God or for theories of God.
To make matters worse, GOD is an utterly incoherent concept. There is no universal agreement among theists on even a single quality of God. Such a situation is unimaginable for any other concept we are expected to take seriously -- if there were no agreement on the essential qualities of a black hole, for instance, the notion would be roundly and rightly ridiculed as a non-concept.
Going back to phlogiston, once it was demonstrated conclusively that the existence of oxygen accounted for observations of combustion, and that phlogiston had no place in the system, no one felt free to simply dream up a brand new definition for the term "phlogiston" and claim that it was somehow the same thing. And yet theists do not balk when this is done with God. That alone should demonstrate the utter incoherence and invalidity of the concept.
Yet unlike phlogiston, God has persisted as a common figment of the human imagination. And there are reasons why we should expect the notion of God to persist, despite the fact that God is not real.
God is a byproduct, a side-effect, of how our brains are constructed. Human beings are built to search for meaning behind events, and we have a reflexive impulse to search our environment for patterns. We also have a tendency to search for human motives behind events, and a deep desire to be loved and cared for. And, of course, a profound fear of death. It is no wonder that our minds generate the notion of God.
And while this may not be a complete or totally accurate explanation of the persistence of the GH despite all evidence to the contrary, it is not trivial that we do indeed have a plausible explanation for the endurance of the notion of God which does not require that there actually be any God or gods.
The response to this state of affairs -- the collapse of the world view which engendered, sustained, and allowed God; the complete lack of evidence for God; the firm establishment of an explanatory framework for our universe which has no place for God; and the existence of a rational and reasonable explanation for the persistence of the GH nonetheless -- has been the rise of intellectual theism which dismantles the very definition of God and removes God from the realm of reality into a purely hypothetical and imaginary space.
In doing so, intellectual theism has attempted to deny the qualities of God which are recognized, even demanded, by the vast majority of believers across the globe -- an intelligent, conscious being who acts within the world.
By invoking this ploy, the intellectual theists may rightly be accused of reducing God to an empty or nonsense concept, or a mere Humpty Dumptyism.
And that is where we stand today.
We live in a post-God world which poses an insurmountable challenge to theists. Given what we know, the claim "God is real" must always resolve to a claim which is empty, nonsensical, contrary to fact, redundant with materialism, or a Humpty Dumptyism.
We have 2 choices -- either God acts within this world in detectable ways, or God does not act within this world in detectable ways.
If the latter is asserted, then God becomes nothing more than an "I don't know what living in I don't know where at I don't know when doing I couldn't say which". In that case, statements about God are equivalent to statements about nothing.
Yet we must keep in mind that God is not a u2. This is essential. The millions of people who worship God, who make the pilgrimage to Mecca, who sing hymns on Sunday, who burn incense at the shrines, who leave food and flowers at the altars, who pray for their children -- they do not, by any stretch of the imagination, consider that God is an utterly unknown thing we have no ideas about whatsoever and have never discovered or thought about. To claim that God is a u2 is Humpty Dumptyism.
We also do not have the option of leaving God undefined if the claim "God is real" is to have any meaning.
To say "God may have caused the Big Bang" is not in any way meaningful if God is an "I don't know". It would be like claiming that flurgs caused the Big Bang, while declining to make any statements regarding the qualities of flurgs.
It is also meaningless to claim that God may have caused the Big Bang (or done anything else, for that matter) while merely pointing to GOD in lieu of a definition. It would be like claiming that flurgs caused the Big Bang while defining a flurg as whatever any flurg theorist cared to dream up as a definition without there being any common set of agreed-upon essential qualities to restrain those definitions.
On the other hand, if it is asserted that God does act in the world, we find that the claims are either empty (unsupported by evidence) or contrary to fact (contradicted by what we know about the world) or redundant (indistinguishable from material/scientific explanations).
And that is where the matter stands.
Under these circumstances, it is unreasonable to demand that anyone concede that the claim "God is real" may possibly have truth value.
The claim is either contrary to fact, nonsensical, devoid of meaning, or indistinguishable from the claim that God is not real.
Therefore, we may dismiss the claim.
God is not real.