Science Fiction & Fantasy Stack Exchange is a question and answer site for science fiction and fantasy enthusiasts. It only takes a minute to sign up.
Sign up to join this community
We know Aragorn is strong enough to reveal himself (due to being rightful owner of the palantir) but why is it that Gandalf does not think he could endure Sauron? Does he, in the back of his mind, think if he reveals himself he will be ensnared like Saruman or that maybe, if he reveals himself, Sauron may change his plans?
Why does Gandalf not think he's ready for such a test?
I always thought of it this way: Gandalf knows that in a contest of wills between Saruman and Sauron, Sauron won. He has no reason to believe he's that much stronger than Saruman. That answers the question as asked.
However consider the risks. Sauron is no fool. He knows who Gandalf is, and possibly his greatest fear is that Gandalf will claim the ring for himself (it never occurs to Sauron that the council would try to destroy the ring, for him it was a question of who would claim the ring first). He knows that Gandalf, of all people, probably knows where the ring is.
Let's say Gandalf picks up the palantir for a bit of banter with Sauron. Sauron will immediately see that Gandalf isn't wielding the One Ring, and he will bend every bit of mental muscle he has to wrinkle its location out of Gandalf's head. He'd see the actual plan (hobbit to throw ring in Mount Doom), he'll see the battle before the gates as the diversion it is. Any hope for Middle Earth is extinguished.
Sauron also learns that Gandalf carries one of the three, and will learn also that Galadriel & Elrond also carry rings, compromising those two and their realms. So the single greatest asset the good guys have (Gandalf) is compromised, as are their only allies.
The risks for Gandalf using the palantir are astronomical, but to what end? What will Gandalf learn that's worth the risk?
Aragon is the safer choice, going for shock and awe, the bloodline & the blade that slew Sauron's corporeal form and diminished his spirit. There were still risks, but as you say, they are mitigated by Aragon's innate right as master of the palantir.
Also consider that Gandalf (like the other Istari) is forbidden from tackling or confronting Sauron directly, he can only help (direct and encourage) others in their struggles against the dark lord.
Aside from the (correct, IMHO) things that Binary Worrier said, in the Unfinished Tales we read this about the choosing of the Istari (although I lifted that quote from Wikipedia where I have read it recently)... emphasis is mine:
Manwë summoned the Valar for a council [- maybe he had asked Eru for counsel -] at which it was resolved to send out three emissaries to Middle-earth and he asked who would go. They would have to lose might and clothe themselves in flesh to win the trust of Elves and Men but this would also imperil them, diminish their wisdom and knowledge and bring upon them fear, the care and weariness of the flesh. Only two came forward; Curumo [Saruman] and Alatar. Curumo was chosen by Aulë among "his" Maiar, and Alatar was sent by Oromë. Manwë asked where Olórin [Gandalf] was, and Olórin, just returning from a journey and coming to the meeting, asked what he wanted from him. Manwë said that he wished him to go as the third to Middle-earth. Olórin answered that he thought himself too weak for such a task, and added that he feared Sauron. Then Manwë said that that was all the more reason why he should go, and he commanded him to go as the third. There Varda broke in and said "Not as the third," and Curumo remembered that."
So Gandalf was, from the very beginning, convinced that he would not hold up in a one-on-one against Sauron.
In this, he very much embodied the idea the Valar had for the Istari: To counsel, guide, and encourage, but not to match Sauron power against power. I do not have a direct quote for the latter, but I am pretty sure I have read about the Istari being forbidden a direct confrontation by the Valar.
So, Gandalf basically followed his own preconceptions about his and Sauron's relative power, as well as the will of the Valar.
The answers by DevSolar and Binary Worrier are spot on. But also consider that Sauron has been in possession of a palantir for a long time and is presumably practised in its use. He also is known to have been great skill in crafting powerful devices, since he taught the elves how to forge great rings, and that may have given him some affinity for the Ithil-stone.
Gandalf had almost certainly never seen a palantir before the fall of Orthanc. Even if he had seen them ages past in Valinor, before they went to Númenor, it's doubtful he would ever have used one.
Gandalf is a lesser being than Sauron. Remember, Sauron was the lieutenant of the evil Ainor who was thrust out into the void. Gandalf can and does engage with a Balrog, who was a lesser servant of the evil one. The contest is so evenly matched that Gandalf is out of things for a bit.
From what I understand, the Istari were sent by the Valar to help Middle-Earth, not solve their problems for them. This explains why Galdalf always runs off in times of need. More so in The Hobbit than in The Lord of The Rings.
