LotR -- Book 5 - Chapter 01 - Minas Tirith

[Firefoot]

"Folly?” said Gandalf. “Nay, my lord, when you are a dotard you will die.”

Another interesting thing about this quote is that it is a nice bit of foreshadowing/foretelling. Dotage is defined as (dictionary.com):

The loss of previously intact mental powers; senility.

I'd say this certainly applies to the despair and death of Denethor, not to be getting ahead of myself to much. The palantir certainly destroys Denethor's hope and sanity enough that he loses his mental powers; he truly does fall into dotage, and guess what? He kills himself, fulfilling Gandalf's words. I had never really noticed this quote before, instead focusing on what followed it, but it really is an interesting line.