Personal Experience Only Positive Proof of God
The following is taken from the "Urantia Book". The revised edited book can be downloaded from Urantia.org website.
“God is spirit.” He is a universal spiritual presence. The Universal Father is an infinite spiritual reality; he is “the sovereign, eternal, immortal, invisible, and only true God.” 1:3.1 (25.1)
Even though you are “the offspring of God,” you ought not to think that the Father is like yourselves in form and physique because you are said to be created “in his image”, indwelt by Mystery Monitors dispatched from the central abode of his eternal presence.
Spirit beings are real, notwithstanding they are invisible to human eyes; even though they have not flesh and blood.
God is primal reality in the spirit world; God is the source of truth in the mind spheres; God overshadows all throughout the material realms. To all created intelligences God is a personality, and to the universe of universes he is the First Source and Center of eternal reality. God is neither manlike nor machine-like. The First Father is universal spirit, eternal truth, infinite reality, and father personality. 1:2.1 (23.4)
The eternal God is infinitely more than reality idealized or the universe personalized. God is not simply the supreme desire of man, the mortal quest objectified. Neither is God merely a concept, the power-potential of righteousness. The Universal Father is not a synonym for nature, neither is he natural law personified. God is a transcendent reality, not merely man’s traditional concept of supreme values. God is not a psychological focalization of spiritual meanings, neither is he “the noblest work of man.” God may be any or all of these concepts in the minds of men, but he is more. He is a saving person and a loving Father to all who enjoy spiritual peace on earth, and who crave to experience personality survival in death. 1:2.2 (23.5)
Those who know God have experienced the fact of his presence; such God-knowing mortals hold in their personal experience the only positive proof of the existence of the living God which one human being can offer to another. The existence of God is utterly beyond all possibility of demonstration except for the contact between the God-consciousness of the human mind and the God-presence of the Thought Adjuster that indwells the mortal intellect and is bestowed upon man as the free gift of the Universal Father. 1:2.8 (24.6)
Through the presence of his fragmentized spirit the Creator Father maintains immediate contact with his creature children and his created universes. 1:2.10 (24.8)
God deal directly with the personalities of his vast creation of will creatures, but he is contactable (outside of Paradise) only in the presences of his fragmented entities, the will of God abroad in the universes. This Paradise spirit that indwells the minds of the mortals of time and there fosters the evolution of the immortal soul of the surviving creature is of the nature and divinity of the Universal Father. 1:3.1 (25.1)
But the minds of such evolutionary creatures originate in the local universes and must gain divine perfection by achieving those experiential transformations of spiritual attainment which are the inevitable result of a creature’s choosing to do the will of the Father in heaven.