The focus of Zen, its main purpose is to take us back to that long forgotten state of mind where the present moment becomes the primary one again, and everything else secondary, if of any importance at all. This shift of consciousness is nothing more than returning to our natural way of perceiving the world around us, the way we used to when we were little children. Back then we had very short past, hence not much of a conceivable future either, this way being able to live our lives with a certain sense of presentness, something we have managed to forget somewhere along the way.
