Brains working towards machine consciousness

I tend to believe nothing is impossible.  Well, I say believe but it is more 'hope', really.  Richard H., colleague, friend and general loon, pointed out to me the other day that:

If nothing is impossible then
there is a finite possibility that something has a probability of 0, i.e. that something is impossible. 

Bother.  The fact that something can be impossible means that it is not true that nothing is impossible. 
It is impossible for nothing to be impossible - but that means we already know of something which is impossible, so perhaps everything else could be possible, apart from the assertion that "nothing is impossible".