Howcome we can control what we say, but we can’t help what we think?

Question: Howcome we can control what we say, but we can't help what we think?
- Keywords:
  brain,
  control,
  say,
  think
Asked by rebz to David, Helen, Ian, rhysphillips, Sarah on 16 Jun 2011.
- Ian van der Linde answered on 16 Jun 2011:
  
  Some very disciplined people can control what they think to some extent, and people with conditions like Tourette’s Syndrome find it very difficult to control what they say, so it’s not true all the time. But in general, our thoughts are our private world that helps us make decisions and control our actions, but speech is about communicating with others – they have different purposes. I certainly wouldn’t want everybody to know that I was thinking about donuts half the time ;o)
- Rhys Phillips answered on 16 Jun 2011:
  
  Our thoughts control what we say so we can think of something and make a decision not to say it.

Question: Howcome we can control what we say, but we can't help what we think?