The contrary belief was once mocked on "Yes, Prime Minister" as:
"1. We must do something.
2. This is something.
3. Therefore, we must do this."
"1. We must do something.
2. This is something.
3. Therefore, we must do this."
1. Nothing is going to happen
2. Something maybe is going to happen, but we should do nothing about it
3. Maybe we should do something about it, but there's nothing we can do
4. Maybe there's something we could have done, but it's too late now