The Shadow of the Past - Gandalf's knowledge

[William Cloud Hicklin]

I think Gandalf was in a position where deduction and simple arithmetic told him it could only be the One, but that was almost too much to believe, and then there was Saruman's definitive statement. There seemed no way the One could have made its way from Isildur's finger to a tunnel under the mountains, and if Saruman could be wrong about the One than surely he could be wrong about one of the others instead (in the first instance, the Seven- maybe one wasn't actually melted by a dragon but simply dropped?). He could not reconcile the data available, and certainly didn't want to make a definitive move until he was certain, or at least more certain. That certainty didn't come until he had found and questioned Goillum.