Good and evil

[Legate of Amon Lanc]

Originally Posted by alatar

Is it that Gandalf's knowledge comes from a more active research than the suspected more passivity of Radagast? Note that Gandalf somewhat aggressively goes searching for knowledge (i.e. Hobbits); did Radagast observe just those flora and fauna that were outside his window?

I wouldn't say so. Gandalf shows the best, the "middle point" between Radagast and Saruman. Where Radagast was passive, Saruman was active to that point that he took charge of other beings rather than just aiding them, helping them understand and letting them choose, as Gandalf did. Also, this is that it's not Gandalf who goes "aggressively searching for knowledge", that one is Saruman: yes, aggressively searching for knowledge. Gandalf searches just out of curiosity, or (more often) what he needs: the Scroll of Isildur, for example, he searches for only when he is in need of it (which could be considered even a little setback). But Saruman...

Originally Posted by Elrond's Council

"(...) The white page can be overwritten; and the white light can be broken."
"In which case it is no longer white," said I. "And he that breaks a thing to find out what it is has left the path of wisdom."

Emphasise mine, of course. I think that's one very important thing to consider. Or the same chapter:

Originally Posted by Elrond's Council

"It is perilous to study too deeply the arts of the Enemy, for good or for ill."

As Saruman did this, hungry for knowledge (and so later, for power).

And finaly, we have the testimony of Treebeard:

Originally Posted by Treebeard

[Saruman was] always eager to listen. I told him many things that he would never have found out by himself; but he never repaid me in like kind. I cannot remember that he ever told me anything. And he got more and more like that; his face, as I remember it – I have not seen it for many a day – became like windows in a stone wall: windows with shutters inside.

So I think where Radagast shows passivity, Saruman shows - as alatar said - aggressivity in seeking knowledge; and Gandalf, therefore, presents the "mild middle point", the best alternative.