14:2.4

None of the physical beings of the central universe would be visible to Urantians. Neither would any of the physical stimuli of those faraway worlds excite a reaction in your gross sense organs. If a Urantia mortal could be transported to Havona, he would there be deaf, blind, and utterly lacking in all other sense reactions; he could only function as a limited self-conscious being deprived of all environmental stimuli and all reactions thereto.