After having stated that infallible truth, the next step is to define the noun "God".
a loving spirit and almighty creator?
a concept which gives meaning and direction to an otherwise random assimilation of events called "life"?
a level of happiness and contentment that can be reached only through wise obediance/adhereance to a set of timeless principles recognized and gathered throughout thousands of years of life experience? (You "see God" in the realization that your life is filled with great friends, family, real security, self-confidence, respect from community, no deep troublesome secrets keeping you looking over your shoulder...) In this context, God doesn't physically exist but is rather mentally and emotionally attained: Buddhist enlightenment(?).
a perfection, an omnipotent presence transcending the cosmos, defining righteousness and justice?
an imperfection that created a "world gone wrong", who desperately wants to make things right through religious teachings and gospels?
Referring back to the title of this post, I guess there are two words to define: first "God", then "exists".
Can a concept be considered as existing? Then no matter what this ensures God's existence even if as in the form of a mere abstract construct.
No matter what then, God exists. In existing (by whatever acceptable consensus defining "exists"), he gives some people direction, assurance, wisdom, aid, love, happiness, answers to difficult questions, etc. The next question is how and in what context?
You know what though? I guess by the same criteria Santa Clause exists, which may or may not ruin my whole point. Either way, even if by mere idea or concept, God exists. Also if somebody were to suddenly and unexplainably overcome a hopeless situation (like cancer, aids, a false accusation of murder leading to conviction...) even if by the placebo effect (of their belief in God), then I contend that not only does God exist, but he also works miracles. So whether spirit or idea, God works in our lives daily.
"I think therefore I am"
"I think about God, therefore he is"
...perhaps even: "I am, only because God thought about me"
just a few thoughts ... by the way, great post once again Kyle.