We all tend to feel as if there is something wrong with us if we don't know the answer to a question, and we become immensely embarrassed if it turns out that we have been demonstrably mistaken about some matter of which we had once felt unshakeably sure. No wonder we all try to keep our heads below the parapet and avoid being drawn on topics that might cause us to reveal ignorance.

 It is not just actions that speak louder than words. We can read plenty, too, into inactivity. When somebody doesn't do something, it can say as much or more - especially if it is a something that they said they were going to do. 
The laws of 'cause and effect' are not always as straightforward as we might wish. Things happen. We think, while they are happening, that we know why they are happening. Then, later, we realise that they have happened for an entirely different reason. If only, at the time, we had understood more and assumed less, we would have made other choices.