Can't Thunderclap while silenced

It is called "Thunder" and "Clap." That implies some noise. :)

Seriously though, silence isn't a dispel. Dispels are tied to magical effects. Silences are just tied to things that (more or less) logically require an audio component (in the game fiction -- I'm not talking about your sound card) to work. Most caster spells qualify but some other abilities do too.

Q u o t e:
As soon as I read that I thought, "Man, GC just opened up a can of worms". I understand where you are coming from but now we get to read 10 pages of "Wait, I don't have to make noise to do X, why does it obey silence!?"

That response is certainly possible, but I figure part of what I can do out here (in exchange for all the feedback we get) is offer the occasional intent behind a game decision. Sometimes players can get us to question those decisions, but in cases like this it's going to take more than "It doesn't seem to *me* like silence could stop a Thunder Clap." Trying to arbitrate how the physics of magic should work is a pretty futile exercise. :)