If you're using 'fourth dimension' for time, then the human brain is entirely used to dealing with four dimensions.
You're assuming the "prophet" is experiencing time linearly in the visions, which is not necessarily the case.
As a prophecy we all know and love, consider the return of King Arthur. If there was a real Arthur, he was nothing like the legends that sprang up around him. There's no specificity as to when or how he will come back, only "in Albion's darkest hour." If he didn't return during the Blitz (idea: what if he had?), then when?
So who created the prophecy? Nobody knows, no way to tell. Will it come true? Well, it's based in fiction, so probably not. Most "prophecies" in fiction should be treated the same way.
I agree with the general feeling, prophecies in a story act like a book of PlotCoupons
. The plot has to fulfill the prophecy because the prophecy is there to drive the plot—it's lazy plotting and what's more it's circular reasoning.
Under World. It rocks!