How loudly should we think?

Thinking out loud… Talking to oneself… Holding debates with yourself… Humans range from constant stone silence to screams qualifying them for the spin bin. Personally, either extreme seems kind of freaky to me. Certainly, those who bellow their thoughts as they walk down the street are way above what’s acceptable. But it’s almost equally disconcerting to interact with someone who thinks in absolute silence at all times, never mutters under his or her breath, never lets thought even show on their face. It is a bit like meeting the latest model of wax figure from Madame Tussaud’s Wax Museum, the moving-wax version. Even though they move, their absolute silence and the constancy of the expression on their face leaves me feeling that I were to inspect, I’d find that there was nothing but wax from one ear to the other. Nobody is home inside.

So how loudly should we think? Is complete silence at all times the target? Is occasional muttering under the breath allowed? Can one talk to the TV, disputing political lies or celebrating the home team’s triumph? How about stage asides for comedic effect among friends in the room? Is it OK to openly debate the pros and cons of something you are considering? If so, does it matter whether you have the expectation of privacy, or are are holding your debate in a crowd?

I’m not talking about Tourrette syndrome or neuropsychiatric disorders that are not under an individual’s control. The question is, given that you control the volume dial, where on the mental volume scale do you come down, and is that where you would like to be?

Please think through your answer silently, so I can think about my comments in reply to other answers here.