LotR -- Book 2 - Chapter 07 - The Mirror of Galadriel

[Guinevere]

Originally posted by Davem:

And a mirror reflects the viewer’s own image back at them. Well, in this case it reflects their inner self, their hopes, fears, desires.

Well - to me it doesn't seem that the things that Sam and Frodo see in this "mirror" are reflections of something in their minds! They see things that are happening in the present ( like Frodo sees Sauron's eye roving and searching for him, for the Ring. This is, imo, something external. After all, Sauron IS looking for the Ring and its bearer!) and things that are going to happen in the world. The significance of some of these future visions isn't known to Sam and Frodo and they are just as mysterious to the first-time reader! Only at repeated readings we know what they show: Sam sees Frodo lying pale and unconscious after Shelob's bite, himself in the tower of Cirith Ungol, searching for Frodo. Frodo sees also things of the far past: Elendil's ship coming from the west after the downfall of Númenor, Osgiliath, Minas Tirith, and then again things of the future: the corsair ship with Aragorn's banner coming up the Anduin to the battle of Pelennor, and finally the Elven ship passing into the West. These visions can't have come out of his own mind!