This is a question about Logic. I've read in a book by Michio Kaku, _The Physics of the Impossible_, that it may be possible to receive a signal before it was sent. This to my way of thinking would violate the logic behind causality. And yet on a social level we are effected by what happens in the future. An example would be Christmas shopping.
My question is can an effect precede a cause, and if so what does that mean in relation to actuality and reality?