Snape paused for a moment, apparently to savour the pleasure of insulting Harry, before continuing,
‘Only Muggles talk of “mind-reading”. The mind is not a book, to be opened at will and examined at leisure. Thoughts are not etched on the inside of skulls, to be perused by any invader. The mind is a complex and many-layered thing, Potter … or at least, most minds are … .’
Harry Potter and the Order of the Phoenix